utopian isotope Posted February 2, 2008 Report Share Posted February 2, 2008 How do you post an audio clip here? Since Photobucket doesn't allow mp3 or any other audio-formats? Do I really have to have my own website, where I can upload the files, so that I can link them here ? Link to comment Share on other sites More sharing options...
col Posted February 2, 2008 Report Share Posted February 2, 2008 How do you post an audio clip here? Since Photobucket doesn't allow mp3 or any other audio-formats? Do I really have to have my own website, where I can upload the files, so that I can link them here ? There are a number of sites like photobucket but for audio - the one I use is Soundclick check out my sustainer demos on soundclick hmm, I need to get some new demos done... so I need to do some experiments for that to be worthwhile... cheers Col Link to comment Share on other sites More sharing options...
utopian isotope Posted February 3, 2008 Report Share Posted February 3, 2008 (edited) Thanks col, I'll try it. I listened your demos, and they give quite good picture of sustainers possibilities. ---------- Seems that some of that annoying fuzz-element came from lower strings rattling against frets. So I decreased lower frequencies on that eq. Clean tones sounds much better now, although there is still subtle amount of fuzz (clipping/distortion). Addition: I also replaced battery with mains adapter. It seems to give more headroom to sustainer, so that it doesn't clip so easily. Not too practical, but as I'm testing things, it doesn't bother. When enough testing is done with my present sustainer, I'm going to replace it with Ruby/Fetzer for better efficiency. Edited February 3, 2008 by utopian isotope Link to comment Share on other sites More sharing options...
col Posted February 6, 2008 Report Share Posted February 6, 2008 (edited) Seems that some of that annoying fuzz-element came from lower strings rattling against frets. ... Clean tones sounds much better now, although there is still subtle amount of fuzz (clipping/distortion). Hehe, there are so many different possible causes for background fuzz in this project: here are a fewEMI: in these cases, distortion in the unwanted interference signal will be audible, so it can be at least partially avoided by making sure there is no(or very low) distortion!.. (of course, there are as many possible causes of the distortion as there are ways for EMI to get from driver to pickup ) EMI from driver reaching pickup through the airEMI from cables reaching pickupEMI from circuit reaching driverguitar strings acting as an EMI bridge between driver and pickup [*]pickup and driver = parasitic transformer causing clipping in interference signal [*]Shared earth of pickup and driver allowing one to load the other [*]output cap on circuit causing distortion in low frequency signals (to avoid this completely we'd need a 1000u cap!) [*]physical vibrations from driver reaching pickup [*]strings hitting frets [*]faulty components or bad construction or driver and/or circuit [*]other faulty gear like stomp boxes or amps causing fizz that we didn't notice before because we didn't listen hard enough [*]The ghost of Jimi diggin' our groovy sustainer antics I'm sure there are others that I've missed, but you can see the trouble - fuzz removal is like peeling an onion. Col Edited February 6, 2008 by col Link to comment Share on other sites More sharing options...
psw Posted February 6, 2008 Author Report Share Posted February 6, 2008 Seems that some of that annoying fuzz-element came from lower strings rattling against frets. ... Clean tones sounds much better now, although there is still subtle amount of fuzz (clipping/distortion). Hehe, there are so many different possible causes for background fuzz in this project: here are a fewEMI: in these cases, distortion in the unwanted interference signal will be audible, so it can be at least partially avoided by making sure there is no(or very low) distortion!.. (of course, there are as many possible causes of the distortion as there are ways for EMI to get from driver to pickup ) EMI from driver reaching pickup through the airEMI from cables reaching pickupEMI from circuit reaching driverguitar strings acting as an EMI bridge between driver and pickup [*]pickup and driver = parasitic transformer causing clipping in interference signal [*]Shared earth of pickup and driver allowing one to load the other [*]output cap on circuit causing distortion in low frequency signals (to avoid this completely we'd need a 1000u cap!) [*]physical vibrations from driver reaching pickup [*]strings hitting frets [*]faulty components or bad construction or driver and/or circuit [*]other faulty gear like stomp boxes or amps causing fizz that we didn't notice before because we didn't listen hard enough [*]The ghost of Jimi diggin' our groovy sustainer antics I'm sure there are others that I've missed, but you can see the trouble - fuzz removal is like peeling an onion. Col That is such a good summation of the situation as far as fizz/fuzz/EMI/parasitic or whatever distortion... There are a few there that I had not even quantified...hmmm...more food for thought... I have found that "a little fizz" if disguised even with a mild overdrive is perfectly acceptable...at least for me. I also have a feeling that it may not be able to apply strong sustain (non-gain control) without this effect occurring at high, infinite sustain modes. If one tries to create feedback naturally, either via high volume or by a particularly resonate guitar or by things such as pressing the guitar head onto the amps speaker baffle (a poor man's model C sustainiac and old studio trick)...some distortion seems to be evident. Heck...even the eBow makes a feature of the distortion running the device right up and over the pickups...careful listening and reading of their promotional material indicates pickup preferences too...hmmm However, a clean sound is not only the "holy grail" of this project...it is necessary for efficient operation to aim as far as possible towards that end. To my mind, I have always sought to retain the characteristic tone of an instrument and the device used to enhance technique. I can also see however a definite quality in "unrestrained" feedback as featured on my sustain-o-caster for instance. Without AGC, the feedback loop will continue until the strings themselves can not vibrate any further. Usually, they will start hitting frets and things before then. Certainly it would seem that, besides all that is said above, the shear physical vibration of the strings in such an unnaturally powerful way will cause some distortion, if only in the physical way in which the string vibrates. AGC can restrain the effect a little too much, loosing the dynamics and touch sensitivity even though providing infinite sustain. As one of the possible characteristics of the device is the potential to push the strings hard and for notes to bloom and evolve, it is not therefore something I yearn for to the nth degree. Compromise and individual choice should be the key. If a players style is distorted already and they want this effect...then go for it...but there is a beauty in subtlety and, while distrotion can be added to a clean signal...it is near impossible to remove. In my later circuits, I have aimed to achieve both of these effects by linking the AGC into the gain and the zobel network in order to derive a range of effect. It should be noted that there is more to this thing than simply infinite sustain...the ability to control attack and decay, the harmonic function...even some distortion, all are important features. Even subtle effects at low volumes where notes decay relatively naturally (no infinite sustain) but, in harmonic mode...die with a little harmonic lift is a very nice effect, if subtle. Especially with the DIY version with very simple preamp/amps like the F/R solution will most likely necessarily suffer some distortion effects...but still, with good technique, this can be limited to some degree. Col has been able to get far cleaner sustain because of a far more sophisticated automatic gain control (AGC) circuit and using a dual coil, EMI cancelling driver design. I have continued to work on single coil drivers and the pickup/driver combo concept in my more recent designs. I do have other designs and hopefully some of these will come to light in the very near future. For instance, I have just tried winding a design with an active shield and, if all goes well, one coil of an HB prototype...the epoxy is still setting. Mostly though, I have been concerned by the switching and installation of late. This is not an easy thing to install, let alone getting it working properly. I must say, even my better ideas presented lately seem to suffer from switch noise still...so there is more work to be done on that alone! --------------------- Some news however...as things progress, I hope to make use of my own personal web site to provide resources and such for anyone interested in these things, in a far more condensed and graphic way. I also intend to put up sound samples and such in time. The DIY side of things will always hold a central interest for me, regardless of commercial considerations and I hope to be able to provide as much material as possible as an adjunct to this and related threads. Posting Audio has always been something of a problem. I used soundclick too but found it a little unwieldy. With my own site, I hope to be able to demonstrate not only successful implementations but also some of the symptoms of which we discuss. For instance, what does this EMI/fizz distortion sound like, what should be expected for a DIY version, those kinds of things are very difficult to explain in words and the symptoms can often be confused. A guitar with a low action will rattle the frets, spin off harmonics and such (unless restrained by AGC)...at high drive these strings are being worked hard, there is no way around that. Being driven hard...that means more volume, overloading the amplifier input causing distortion and overloading the sustainer circuitry, also resulting in a distorted signal to the driver and to any EMI that may get through. One other thing to consider is that with a fixed position driver exciting the strings in the way that it does, with phase differences, low amplifier headroom and other things coming into play...these strings, even if not driven hard and restrained by AGC will most likely not be vibrating in a wholly natural way and so could be considered to be distorted. Mi9nimisation and compriomise, especially with DIY versions, but even with commercial units...is key. Web site creation is very new to me, but the potential is there and I have taken the plunge to be able to provide the resource and to utilize it here and elsewhere. As far as the commercial viability of my own version, it remains to be seen. The switching and things are a big obstacle as is quality control...not to mention the high investment in resources and time. I am still hopeful and doing a fair amount of work, but some problems, such as col describes, will always be a balancing act. Hopefully, I will be able to make available circuits and wire kits or even driver coils to complete systems to aid in the costly and difficult problems in finding some of these things. I have found it almost impossible now to find the 0.2mm wire in small quantities that I used to get...and it is not being stocked any more. As I am making so many...I use commercial quality and quantity...this may provide an opportunity to spin off and post cheaply such material (one of the more difficult parts for people to find it would seem) and so allow more people to be involved, develop and solve problems and come up with innovative installation ideas as well as develop new techniques and musical uses for the thing...well, that is the intention. This thread has come a long way (since May, 2004 is it?) with so many contributions, but I still feel there is something missing. While further development is necessary, engaging and entertaining, I still feel that a definitive guide to creating a successful DIY version is lacking. It would seem that this is something important for the building and improvement of the device. Exactly what needs to be explained (should it go back to explaining the fundamentals of how it works and definitions of things like EMI and why it is a problem?) would be interesting to know. I have tried to switch my way of working (typically penciling on the back of envelopes) so that layouts and such are far easier to read (I hope you have noticed this in recent submissions)...now all I need to do is reduce the word count!!! On that...later...nice work there col...pete Link to comment Share on other sites More sharing options...
col Posted February 6, 2008 Report Share Posted February 6, 2008 I also have a feeling that it may not be able to apply strong sustain (non-gain control) without this effect occurring at high, infinite sustain modes. It is certainly possible to apply strong sustain while using gain control... I'm also sure that it is possible to remove audible fuzz and still use a 'high infinite sustain mode' (whatever that is). If one tries to create feedback naturally, either via high volume or by a particularly resonate guitar or by things such as pressing the guitar head onto the amps speaker baffle (a poor man's model C sustainiac and old studio trick)...some distortion seems to be evident. In my experience, that depends on guitar and amp settings - of course, the tone and 'quality' of the sound will be different, but it is possible to get sustain at high volumes without fuzzy distortion. However, a clean sound is not only the "holy grail" of this project...it is necessary for efficient operation to aim as far as possible towards that end. To my mind, I have always sought to retain the characteristic tone of an instrument and the device used to enhance technique. Certainly it would seem that, besides all that is said above, the shear physical vibration of the strings in such an unnaturally powerful way will cause some distortion, if only in the physical way in which the string vibrates. Now the definition of 'distortion' is getting very blurred indeed - to the extent that it is losing its meaning! I would suggest that we stick to a definition like 'clipping of the signal resulting in a fuzzy or crunchy quality to the sound' or 'a noticeable fuzzy or rough quality to the sound'... this is why sustainiac use the word grunge. AGC can restrain the effect a little too much, loosing the dynamics and touch sensitivity even though providing infinite sustain. As one of the possible characteristics of the device is the potential to push the strings hard and for notes to bloom and evolve, it is not therefore something I yearn for to the nth degree. Compromise and individual choice should be the key. If a players style is distorted already and they want this effect...then go for it...but there is a beauty in subtlety and, while distrotion can be added to a clean signal...it is near impossible to remove. Any technique can have negative effects if not used sensibly - AGC is a technique that can be used in many ways, and certainly doesn't prevent blooming harmonics or 'pushing' of the strings. One thing I'm currently looking at is the use of a less extreme AGC that will just prevent the drive signal from causing clipping in the circuit allowing weaker signals to be amplified more without getting fuzz. This is a depature from my other circuits which effectively switched off the drive when the signal went over the threshold. This type of AGC - basically a brickwall limiter - allows you to have your extreme gain if you want it (distortion and all), but it also lets you boost the weaker strings/frets, so its a win/win. In my later circuits, I have aimed to achieve both of these effects by linking the AGC into the gain and the zobel network in order to derive a range of effect. I've noticed you talking about your new AGC interacting with the zobel... how does this work? My understanding of what a zobel network is and how it functions suggests that if there is an interaction, then its not actually zobel network! so whats happening ? Especially with the DIY version with very simple preamp/amps like the F/R solution will most likely necessarily suffer some distortion effects...but still, with good technique, this can be limited to some degree. Col has been able to get far cleaner sustain because of a far more sophisticated automatic gain control (AGC) circuit and using a dual coil, EMI cancelling driver design. hehe, I've recently taken an old single coil driver and put a 'cage'... not a shield, but as I explained a while back, an external continuation of the core that increases the inductance and focuses the feild. I swapped this for my dual core driver, and it works well. It has similar low distortion characteristics to the dual core. unfortunately, the drive is not quite as good, but I believe that is due to not having a good enough magnet - certainly not as good as the one on my dual core driver.. still, promising results. One other thing to consider is that with a fixed position driver exciting the strings in the way that it does, with phase differences, low amplifier headroom and other things coming into play...these strings, even if not driven hard and restrained by AGC will most likely not be vibrating in a wholly natural way and so could be considered to be distorted. Mi9nimisation and compriomise, especially with DIY versions, but even with commercial units...is key. Hehe, you might as well say that plucking a string distorts it's shape and forces it away from its natural equilibrium, so for a guitar to make a sound you need distortion - quite pointless though :-p Web site creation is very new to me, but the potential is there and I have taken the plunge to be able to provide the resource and to utilize it here and elsewhere. Good luck with the website - it's definitely overdue, particularly for your commercial sideline. If you need any advice or suggestions about web dev, PM me, I've done some web development - right now I'm working on a database driven Library catalogue! This thread has come a long way (since May, 2004 is it?) with so many contributions, but I still feel there is something missing. While further development is necessary, engaging and entertaining, I still feel that a definitive guide to creating a successful DIY version is lacking. It would seem that this is something important for the building and improvement of the device. Exactly what needs to be explained (should it go back to explaining the fundamentals of how it works and definitions of things like EMI and why it is a problem?) would be interesting to know. I have tried to switch my way of working (typically penciling on the back of envelopes) so that layouts and such are far easier to read (I hope you have noticed this in recent submissions)...now all I need to do is reduce the word count!!! Yes, it seems silly that there isn't yet a definitive guide, but there are very good reasons why. Unfortunately, we're not yet in a position to provide anything definitive yet! As we know, this project depends on many variables. Some of these variables are 'external' things like the guitar, the pickup(s), the available materials for the driver magnet, core material, wire etc. Unfortunately, in order for us to provide a single definitive guide, we need to provide a method for people to measure and assess the resources they have and tell them how to use their results to adjust parts of the system in order to ensure a successful outcome. If we cannot provide this kind of instruction, then the guide might as well say - "read the thread, then use trial and error building many divers and circuits until you get one that kinda works for you!". I am some way towards a method for understanding the components of the driver in a way that would allow for this kind of methodical approach, but I'm unfortunately limited by lack of equipment and money The current problem is how to measure the inductance of small coils accurately enough to be useful. I'm stuck because to develop a method, I need some sort of trusted accurate meter to compare the diy approach results with - otherwise, I can't know if they are close enough or completely useless. IF we can provide a plug'n'play method for measuring inductance and mathematically deriving the other variables - particularly inductance factor -) from the results, we can tell folks: how to choose the best materials from what they have availableif these are going to be good enoughwhat dimensions to make the corehow to calculate the correct number of turns of wire for their core When they have built their driver, they can use the same techniques to measure it's actual inductance and calculate its impedance then we can explain how to tweak their circuit for optimum performance with that driver. If we can't provide step by step plug'n'play instructions in this way, then folks will need skill, knowledge, patience and huge resources of time and perseverance, it wouldn't be a Do It Yourself sustainer, it would be a Develop It Yourself sustainer. For a while now, I've been at the stage where I've got all the equations and just need a method for calculating inductance with reasonable accuracy. Then I would have to build a few drivers to test some different theories and do some testing and work out what the best basic setup is as a compromise between simplicity and functionality. This is the main reason why I've not done any further practical driver research - I'm not willing to do anymore trial and error development unless it is at least partly driven by analysis. I have lots of different ideas to test - some will be valid, and some not, but without reasonable accurate measurements and calculations, it is impossible to know if something failed because the idea is bad or because the implementation specs were outside of the 'success envelope' for that approach.. e.g. It may be possible to build a more efficient 'better' driver using heavier gauge wire, but for it to work, the tolerances of the core variables and the amplification circuitry might be much tighter in which case getting a positive result through trial and error would be unlikely, leading to the false conclusion that heavier gauge wire doesn't work. With effective measurements and a little maths, it would be possible to be sure that if the implementation fails, it's the idea thats crap and not just that particular implementation of it! enough, cheers Col Link to comment Share on other sites More sharing options...
psw Posted February 6, 2008 Author Report Share Posted February 6, 2008 Ahhh...col... Yes, well my terminology and "theories" are a little shaky (more practical hypotheseis I guess; the thin driver for instance is an idea borne out and replicated because it appears to work). Nevertheless, significant ground has been made in following these models. I hope that you and others will develop alternative models, circuits and innovative applications...it takes a lot of different minds and approaches and in this realm some confusion in language (especially given the global nature) and misunderstanding because of separation between ourselves and the devices we are working on... Perhaps my web site will go some way to bridging that gap. I too have tried cages and such...but the limitations were in part on the difficulty of construction and of course definitive testing. I am not an engineer or a scientist and even if able to measure my devices, this may not be able to be extrapolated further effectively as my ability to interpret and explain, and for others to understand is limited by shared understandings of such concepts. A prime example is when I have talked of the thin driver as being an effective design because of its "speed". I have often described it as a "fast" driver design...or at least the intention of the design to be "fast". What I mean by this is that it responds quickly to the signal to create and collapse the electromagnetic field creating a closer phase relationship. If phase is off, not only is the device inefficient (it is working against the strings physical movement) it is creating distortions by reinforcing or canceling some of the strings natural vibrations in doing so. As the device is not mobile (as with an eBow) it is in a fixed position along the string length and also takes its signal from another fixed position further along the string (the bridge pickup) and this too can produce phase and other "distortions" as well as inefficiencies. Driver speed is particularly important in the higher strings where they move a lot quicker and the result of large lags in response can actually end up dampening some notes. The thin design is only part of the equation and of the debates that have been canvased here too...thin cores, ferrite and other core materials that do not "hold" to their magnetic states as well, for instance. The other part of the "thin" driver concept is that by limiting the size of the device, I sought to limit the EMI spread and concentrate it below the strings as much as possible. My latest ultra thin designs are the logical conclusion of these ideas. Whether people are following a madman in this direction is entirely possible and until something more verifiable than my "impressions" and unqualified "theories" are put forward, that is all they are...oh, and a lot of failed drivers along the way. My desire to encourage others to replicate the ideas is in a way to offer something cool that appears to work, but also to seek verification and stimulate debate. To date, the thin coil drivers still seem to dominate peoples appraoches. As a side line to the thin driver, it has some remarkable practical applications...such as the pickup/driver combination...and if in fact the thin driver is a compromise design, these real world applications may in fact be worth it...IMHO. Cages and other such strategies have been tried to some and limited effect by me before...but typically in an adaptive way. I have kind of assumed, in accordance with my own biases, that more core and associated material may be slowing the devices down. Then I also have to consider my construction technique, materials and such. I used for instance a row of domestic staples at one point that attached to the bottom of an internal core magnet...these shielding fins were tried in an effort to better focus the EMI and limit it's harmful effects. In the design I am recalling (it has been quite a few years now), there seemed to be no disernable improvement. I had adapted a driver known to work, and while it did not harm performance, there was not enough (if any improvement) to warrant the effort, nor to even document such follies too much as, like many things I have tried, it may have only encouraged others down a road that I am not sure that was going to be ultimately profitable. Bear in mind that, while I was doing these things (about the 20 page mark I suspect, or earlier) I had already had some successes. Many who get very involved and invest a lot in the improvement in driver designs and such, unlike yourself, curtisa, avalon and others, do not come to the debate having tried and succeeded at least to some good extent. hehe, I've recently taken an old single coil driver and put a 'cage'... not a shield, but as I explained a while back, an external continuation of the core that increases the inductance and focuses the feild. I swapped this for my dual core driver, and it works well. It has similar low distortion characteristics to the dual core. unfortunately, the drive is not quite as good, but I believe that is due to not having a good enough magnet - certainly not as good as the one on my dual core driver.. still, promising results. It is good to here that you have been building and testing in a manner that can be compared in this way...well done. Certainly something my work has lacked at times. My designs of the last few years have sought to balance driver design and multi-pickup installations and so are restrained in many respects by practical limitations and compromises. It is certainly possible to apply strong sustain while using gain control... I'm also sure that it is possible to remove audible fuzz and still use a 'high infinite sustain mode' (whatever that is). This means...no AGC...power applied only to the limit of the ability of the strings to be driven. Bear in mind that very few people attempting this project use AGC. Yes, you can have quite a large spectrum of responses from a little to a lot of AGC and there are various types that would be advantageous as you have suggested. Comparing the responses of samples from the non-AGC sustain-o-caster and your own samples...there is quite a bit of difference to the ear. But then, there are so many factors involved and only if such instruments, players and ears were to be brought together, would this be very well illustrated. Restraint in drive is to be applauded (as I have tried to point out, these are the unique and subtle effects often overlooked, and can greatly improve performance of the system), but the AGC is there to limit at some point the runaway effect of a non-AGC circuit like the F/R is it not? Limiting in the extreme settings is advantageous and unavoidable given the type of amplification headrooms we employ anyway, I would suggest. And, you are absolutely right in your quest to improve driver design and efficiency. A more efficient driver means it can run on less power and so reduce EMI effects dramatically. I have grown towards a stance that acknowledges there are limits to what I can do and, what can be replicated by others or are practical to be done for the benefit a slight improvement may make. Also I am aware that much of this territory has already been covered and documented in patents. The more this track is followed, the closer we seem to gravitate towards existing designs such as those by sustainiac and fernandes. All this ideas such as D-class amps, electronic switching, frequency Dependant AGC and phase compensating circuitry are featured in already established products...in the area of driver design, there are many including bi-lateral and side drivers that have not only been suggested but sold as working products. This is because they are sound ideas that work...but to replicate this by moving further and further towards that model seems to be a little pointless...the cost of developing something that approximates these concepts far outweighs the price of simply buying the thing, installed in a guitar even! In my experience, that depends on guitar and amp settings - of course, the tone and 'quality' of the sound will be different, but it is possible to get sustain at high volumes without fuzzy distortion. Fuzzy distortion is to be avoided and is an indicator to me that something is wrong. Often it would seem to be a factor in the additional pickups and shielding of the guitar itself (hence my present focus on installation and bypass strategies). On a single pickup guitar, this should be far less of a problem... Some mild distortion at extreme gain levels, is perhaps a little unavoidable. If this is an "attractive" distortion, that is not so bad...if it is a tinny or fuzzy EMI, crude like distortion, this is not acceptable. Ideally none is acceptable. While your system uses a LM386 at 20x amplification and AGC, the sustain-o-caster uses no AGC and 200x amplification, plus low grade single coils and multiple pickups with a very basic single coil driver. While some distortion is present, to a large extent it is musical...in harmonic mode the distortion can be a little "tinny"...but then I run this without any dampening in the most primitive way, and yet, I still feel that a worthwhile and very musical result is obtained. In my present designs, I am seeking to improve this, a little AGC, an extension of the driver concept...but basically an evolution. Designs like the HEX systems were more of an attempt in "revolution", but to that extent perhaps it "failed". Consistently however, I have sought these two roads over reproduction of already existing designs...perhaps if I had the necessary skills and wherewithal, and the mindset of someone like dizzy (with his bi-lateral phase compensated mid-driver based in part on the hoover patent) I would have inevitably been drawn towards these designs too. this is why sustainiac use the word grunge Do they...where? I am of course at a disadvantage in that I do not, nor never had a commercial sustainer to compare what I am doing to what is already available. In particular, the promotional stuff from sustainaic (sound smaples and clips) are less than inspiring...perhaps someone could do a review. Lovekraft was invaluable as he did in fact own a fernandes model. I have considered buying an eBow...but I am not sure that it would further the work... Any technique can have negative effects if not used sensibly - AGC is a technique that can be used in many ways, and certainly doesn't prevent blooming harmonics or 'pushing' of the strings. Very true...I am sorry if it comes across as criticism. Obviously, I too have been exploring an AGC approach. Inevitably I have felt that the limitations of a small battery operated circuit would result in limits to power, even if it were simply by clipping. AGC is inevitable then, and it is worthwhile to stop short of grungy distortion that to let the circuit simply runaway. It is one of the reasons that I balk a little at higher powered amps...while they could provide more headroom, the runaway effect and associated EMI as more and more power is applied without active or inherent AGC would seem to be of a concern. I've noticed you talking about your new AGC interacting with the zobel... how does this work? My understanding of what a zobel network is and how it functions suggests that if there is an interaction, then its not actually zobel network! so whats happening ? Obviously I am a little secretive at this point in the "production" process. However, the zobel part of my existing design appears to me as a kind of filter/phase compensator consisting of a resistor and capacitor in series. My AGC feeds back through the capacitor and alters the resistance...or so it would appear...resulting in variable values of resistance and capacitance and so attenuating it's effect. As far as I can tell from some of the documents, the "zobel" like elements and various values are a strategy of the phase compensation circuits described in the patents. The FLoyd Rose patent seems to indicate this a bit more clearly as later designs have more sophisticated approaches harder for me to grasp...or it is a happy accident...or I have got the principle and vocabulary wrong and it is just a happy accident that it works. I understand your frustration with me on these points... Hehe, you might as well say that plucking a string distorts it's shape and forces it away from its natural equilibrium Which it does...pluck it hard and it sounds sharp....true, perhaps a little pedantic...I run off sometimes...need my own AGC perhaps... Good luck with the website - it's definitely overdue, particularly for your commercial sideline. If you need any advice or suggestions about web dev, PM me, I've done some web development - right now I'm working on a database driven Library catalogue! Thanks a lot...I used to be a librarian and worked a lot with library catalogues...particularly acquisition modules BTW...but this was many years ago and computing in general is not an area of expertise (obviously, like electronic theory!) A born generalist I am afraid...a little knowledge of everything, and not enough of anything specific perhaps... I will be needing help if it expands into areas that include the subjects of this thread. At present there is a test site up with very little content at all...but the address is www.warmingtone.com, there is a link at the bottom of my posts now. Obviously there is a lot to go with it, however...it will I hope provide me with a resource for posting information and circumvent the graphic and audio limitations of the forum. I may well include a section of articles and may welcome contributions once it is up and running. There had even been talk at one stage of developing a forum specifically on the subjects covered by this thread...this too I have discussed and is a possibility. A separate forum may provide enhanced communication and usability with sections specifically on driver designs or installations...but this is some way off I would imagine and require more involvement than I alone could offer. It would be a nice advancement given how long and convoluted this thread has become. Yes, it seems silly that there isn't yet a definitive guide, but there are very good reasons why. Unfortunately, we're not yet in a position to provide anything definitive yet! Well...there probably is never going to be a "definitive" guide. People will notice that the sustainer tutorial was not initiated by me and the opening disclaimer to that thread was because the author had not previously published his results and even I had not achieved a "definitive" installation. I was also concerned about the implications of saying that this was it, and since it was interpreting my ideas in a "tutorial" form that implied a definitive approach (ie...do this and you will have a practical working sustainer) I did have some reservations. As it stands, this tutorial did have significant impacts. I quickly posted my own work with it to try and round it out however. The tutorials biggest impact was the putting forward of the fetzer/ruby as a viable circuit. The driver was not what I would have hoped for and the results reflected that. It would have been nice if these had been sorted and vetted before it was published as a "tutorial". The wire gauge was "wrong" and the use of neo-magnets also a little suspect (didn't they come from disk-drives or something) and the whole thing was never fully installed and didn't work in harmonic mode. It never tackled problems of installation and use with multiple pickups either. Unfortunately the member didn't stick around or complete or develop it further as there was still a lot of promise there. However...as limited as some of the technology may seem...some guides are possible and as people are successfully doing it, how this is done could be much better documented and treated as a guide. A guide could even be devised for experimenters and a glossary of terms seems to be needed :-p If we cannot provide this kind of instruction, then the guide might as well say - "read the thread, then use trial and error building many divers and circuits until you get one that kinda works for you!". I don't know about that. I have actively tried to persuade people not to try to read this whole thread...much of it is obsolete or irrelevant now and at best it is confusing....many times misleading. It was written like this post as a stream of consciousness in many respects...a bit like a blog...I think some severe editing and condensing and a presentation of the salient ideas is more than overdue. As we know, this project depends on many variables. Some of these variables are 'external' things like the guitar, the pickup(s), the available materials for the driver magnet, core material, wire etc. Unfortunately, in order for us to provide a single definitive guide, we need to provide a method for people to measure and assess the resources they have and tell them how to use their results to adjust parts of the system in order to ensure a successful outcome. Well...this is something that perhaps I took too far in my ambition. If it weren't obvious before, and it surely isn't so much anymore...my "commercail" intentions were purely to rectify these problems. Of late, I am thinking I should step back a little and provide more for the development and the DIY than to try and compete with a complete system at this stage. The work I am doing was and still is based on these very issues. Too many variables, materials and skill levels with a wide but often ambitious expectations and a laudable desire to participate with limited resources. Sometimes, people just want a workable sustainer alternative. The original intention was this. Many reported having trouble finding parts, particularly suitable wire. I too have trouble now except in commercial quantities. I have provided wire on occasion gratis, but mail is a bit of a killer...bankia as a reward for the fabulous DIY layout software is a prime example. A "definitive" basic circuit for the project has always been required too...the fetzer/ruby is a design cobled from the runoffgroove guys designs and is not purpose built for it...I used an alternative and suggested some modifications...but I was never fully convinced of this as the prefered "standard" basic circuit. Such a design would help with consistency too. The development then was to see if it were possible to devise such a circuit and provide the parts and wire to offer some consistency. However, thinking along the same lines...there is obviously a broad range of quality of coil construction and materials that can severely hamper performance. Could it be that I could just wind the coil and supply that without magnets and cores to be used as is. What design would be most suitable...the DIY 3mm coil...or if I were to go to this trouble...should I follow this design to it's ultimate conclusion...the ultra thin, highly condensed, epoxy saturated, self supporting bobbinless, coreless coil? Hand winding was never going to be an option...so a machine needed to be developed (a lot of time and expense there)...and if it were to be something to be ethically be sold by me, and meet the aims of consistency...a higher level of professionalism would be required in it's construction and quality control. So...my present work is on the new circuit that I developed that entails a simple lm386 amplifier with basic preamp and some AGC elements...not a definitive design, but a purpose designed circuit fro this application that works and is an improvement...plus, an improved circuit design. Given that this is pretty much a complete "system" the idea of making it a "product" restrained it in some ways and certainly has held things up. And, perhaps strayed from the original intention. So...should I take what I have and allow it out to experimenters and DIY'ers as originally intended? At the present time, I am trying desperately to take these prototype elements and solve the problems of switching and installation. Providing the materials does not solve the application of them and I am hesitant to release things like this without having the answers. All of this costs money and an enormous amount of time, thought and energy of course. The only way it could work is if I can recover the expense of having it built in some quantity...or at least circuit boards built. But then, if built in even more quantity, it could be constructed for me and be ridiculously tiny (the circuit is only 37x22mmm on vero!)...even then, the costs of machining the coils and hand building them, plus the risks of working with epoxy...is a little bit of a disensentive...it also means that I need to commit to a design in both coil and circuit....hmmmm So, perhaps that helps to see where I am coming from and where I am trying to go. I can not get there alone, nor could I have come this far without the active participation and contributions of the many people over many years on this thread. But we are not there yet and, as is the nature of things...a definitive guide will never be truly achieved... All the problems associated with this that prevents it being a "plug'n'play" device seem to be forever a curse. I have just failed to complete a cheap strat installation with all the usual problems. Squeal in harmonic mode...only low string response, distortion...and this is with my new designs and methods. A pop on both switch on and off!!!! Very disheartening...yet I have had successes. I will be trying again in the next few days on the "test" guitar with removable pickups and getting back to some basics. First....trying it with only a bridge pickup...then as a two pickup guitar. I will be rebuilding the driver and the circuit to eliminate those problems too. As for more adventurous things...I appear to have successfully built a coil with the bulk of the winding in the inner part one way, and then an outer layer wound in the opposite direction of about 20% of the resistance the other. So in effect, two series wound coils one around the other. This is based on my present processes and design criteria and so is strat pickup sized and only 1mm thick! As a result, it should be directly swapped out with a conventional coil of the same type. My intention with my HB coils is to make them even thinner and chain two 4 ohm coils together. I also created a modified version and fitted it into a tele chrome covered neck pickup (fender SCN) with a powdered iron core that sits on top of the pole pieces...this is for yet another project guitar I am working on. I am probably spreading myself too thin...but it is hard to fight ones own nature and, I still suffer a lot of major trials and tribulations in real life that are severely hampering progress too. Anyway...a mega long post I realize...I really need to edit in a word processor perhaps and post later...that will be something for the web site perhaps so it doesn't get out of hand. I have also been exploring a more graphical approach to my more wordy excursions as I mentioned...stand by for some more illustrations in the area of installations... pete Link to comment Share on other sites More sharing options...
col Posted February 7, 2008 Report Share Posted February 7, 2008 It is certainly possible to apply strong sustain while using gain control... I'm also sure that it is possible to remove audible fuzz and still use a 'high infinite sustain mode' (whatever that is). This means...no AGC...power applied only to the limit of the ability of the strings to be driven. For the strings to be the limiting factor, the power would needs to be huge - we would need a mains driven unit and a significantly larger inductor ! There is a point after the signal starts to clip where adding more gain doesn't have much impact on the effect other than to increase background fuzz and waste the battery... It is possible to use AGC to bring the quieter signals closer to this level, and prevent the strong signals from going way over it... so what you get is a more responsive more alive system when playing difficult string/fret combos.. and at the same time slightly better efficiency with no major difference in response in other areas... AGC can help get closer to the natural limit of the system without exceeding it (exceeding the limit is not going to make the thing wilder and more fun, just noisier, less efficient and more trouble) this is why sustainiac use the word grunge Do they...where? I am of course at a disadvantage in that I do not, nor never had a commercial sustainer to compare what I am doing to what is already available. this is taken from the sustainiac stealth plus installation guide (available on their website) "11. GRUNGE/SQUEAL TEST AND ADJUSTMENT OF MAGNETIC FIELD CANCELLATION TAB: If you have squeal and/or grunge in your guitar signal, you might need to add a tab...." If it weren't obvious before, and it surely isn't so much anymore...my "commercail" intentions were purely to rectify these problems. Of late, I am thinking I should step back a little and provide more for the development and the DIY than to try and compete with a complete system at this stage. I think part of the problem is that selling a ready-to-install system doesn't actually solve any of the problems - there are already off-the-shelf systems available... The issue here is how to make a 'DIY sustainer' more accessible, any ready (or part) made system is by definition not a 'DIY sustainer' ! cheers Col Link to comment Share on other sites More sharing options...
psw Posted February 8, 2008 Author Report Share Posted February 8, 2008 Ok... So, I built another amp circuit and a different coil (same design) on a true single coil with alnico poles (staggered, typical strat). I am using a duncan designed HB (jB model copy) in the bridge position on my test guitar (strat without scratchplate for easy pickup, driver and wiring changes. At the present moment the neck pickup (on which the driver sits) is not connected. It works pretty well, in fact so well that only a small range of control is possible for the drive control...so it works on minimal gain. With a 100uF capacitor I am getting a good sustain with "mixed" harmonics on the lower strings at higher gain settings. In harmonic mode, the thing is sustaining but is more susceptible to noise/grunge. I have no tone wired and the volume pot is a 2Meg. When turning down, there is some high frequency noise...but only in harmonic mode. Taking curtisa's advice, it will sustain even with the volume turned down. I did however replace the input 1meg resistor with a 10meg resistor...nopt sure that that really had a lot to do with it. Bearing in mind that there is only one pickup, there appears to be no switch noise. However, on/off at present is by removing the battery, so not conclusive. I will attempt to set it up with the new coil design with dual concentric coils. This is approximately the same resistance (about 7.4 ohms) and the same size and depth...it came out really well. This is a design that I have consistently failed to make successfully before, and is one of the benefits of my present methods that I can now do something that can be comparatively tested and that this design can be given a proper test. Perhaps tomorrow... Meanwhile...it is possible to set this to a preset gain with the trim pot and leave off the gain control...especially since it is working this well with this set up. I really like the harmonics possible in the present normal mode...some are touch sensitive, pitch sensitive and are prevalent in the higher gain modes. In harmonic mode with the driver leads reversed, the output is lower, the harmonics not so strong and the amplifier struggling to reproduce these sounds. What I was wondering is if it would be possible to have some kind of pot control to adjust the value of the output capacitor. If the output cap was something like 220uF, you get very good fundamental sustain...at 100uF, a nice mixed mode...what would happen if the cap was as low as 10uF...would I get better harmonics all round? If so, this could replace the crude phase switch and fix some of the noise associated with it. If not a pot, for sure a rotary switch would work, switching in a variety of caps for different effects, perhaps even a double pole rotary that inserts different resistor values into the gain settings too. What do people think of this scheme? On the observation front, I don't think I have mentioned this before, but if the poles of the driver (remember that the pickup is not connected and so they are not grounded) touch the strings (the strings are grounded) you get an incredible shrieking effect. More so in harmonic mode I think...but either way, overwhelming. This happens occasionally on this guitar because the pickups are held in with modeling clay! (as a side note, it is important that the pickup/driver cant vibrate so on some guitars, this may need some better fitting...normal pickup springs that are fairly stiff seem to be fine). I think that this may be part of the reason for the last strat failure, it would seem that the poles of the pickups seem to be grounded and even with the wires lifted, this effect seems to come into play...still a mystery... I mention this as it may be relevant to others with these kinds of problems...the noise can be sent down the strings into the grounding wires...even some shielding may cause problems. I suspect that a lot of "fizz" is transfered this way, if not to ground, but along the strings and into the bridge pickup and thus into the signal causing distortion. I am not sure that there is a definitive answer to this, dual coil drivers are probably better at reducing this kind of thing. The hope is that the 70/30 driver/shield coil may help too. We will have to see! I had been a little concern that in the last month, although not a lot has been done in practical terms, much that has been done has been faulty or failed...so a bad run there...hopefully this is a sign of better things to come. Anyway, a new driver and control proposition, both again setting the DIY sustainer apart from the commercial units. There are quite a few youtube sustainer demos BTW, very hard to get a definitive appraisal of the performance. If anyone has one or played them, perhaps they'd like to report on the performance...particularly with a clean tone and if there is any noise or distortion, switch noise or other features worth noting. There was one on a Jag I think that was pretty clean and seemed not to suffer any switch noise...but video is a little hard to appraise the thing. Anyway...will attempt to post some of my switching ideas soon, but they are on a different computer so will have to wait. Perhaps by then, I will have tested some of the simple ones with the present setup and they could be added to a "definitive guide" or set of known working procedures. later... pete I think part of the problem is that selling a ready-to-install system doesn't actually solve any of the problems - there are already off-the-shelf systems available... The issue here is how to make a 'DIY sustainer' more accessible, any ready (or part) made system is by definition not a 'DIY sustainer' ! Well...one man's Ikea is another's DIY. The issues of installing and rewiring alone is enough to qualify for DIY, IMHO even with a commercial system. Some would say that anything short of designing and building something without help is not really DIY, but that kind of makes things like this thread a little of a nonsense. As I see it, many are capable of installing and making valuable contributions but lack skills and in some areas, even the materials to successfully complete the project. Initially, I had looked into getting the parts and supplying them as a kit, but the expense of this was a bit much, even at cost in any small quantities. Once I had devised a circuit worthy of replacing the F/R solution suitable for this project (although of course not a definitive circuit), and looked into making circuit boards, it was becoming apparent that some were having problems with building circuits even with the F/R and there may be some call in me soldering them together (may even be easier than packaging and instructions on DIY)...then it was looking as if it may be cheaper to get the boards "populated", prebuilt...but then that would require a greater number...but once you get to that stage, it may as well be shrunk down and supplied with SMD's and populated. The same applies to the coil, supplying the wire (still an option) does not guarantee quality of construction. Even with the right materials, this can be problematic. If I were to make them the old way (and occasionally I am asked), I would need to modify a pickup...and that can be a little time consuming by hand. Machine making them for consistency and epoxy setting them for ultimate potting was an obvious avenue. By this stage it is really only some switches and wiring to be a complete "system". Over the years quite a few people have DIY'ed with computer speaker amps and pre-built or kit modules as we have seen recently. Use of stompboxes for preamps...shucks, one went so far as to use a PA amp and not even bother with the coil winding process...all valuable experiments I might add, but not quite the kind of usable device that many are hoping for and very difficult to quantify any apparent innovations (like wire loops) as the whole system is quite a bit different. Using an eq as a preamp has some interesting possibilities for instance, but can also be used to "cheat", buy playing down the high frequency distortions, and with it often part of the guitars sound too... Still, it is DIY but after all this time, I feel an expectation for more to have come of all this than these crude "experiments"...at least some more definitive procedures to effectively build some kind of sustainer in an actual guitar...even if not "the best" possible driver and amp, or whatever. If people had a sustainer guitar, it is a simple matter to build ones own circuit designs or drivers and swap them out...as I am presently doing...but until you have something that works to start with, people will be in no position really to contribute effectively in development. While there are commercial systems and I have always been an admirer and recommended them, unless you really want to DIY...DIY and my system are still likely to be cheaper and have other significant advantages for many. The more people using any system, the better it is for development as use will inspire more development directions. IMHO. Link to comment Share on other sites More sharing options...
col Posted February 8, 2008 Report Share Posted February 8, 2008 (edited) I think part of the problem is that selling a ready-to-install system doesn't actually solve any of the problems - there are already off-the-shelf systems available... The issue here is how to make a 'DIY sustainer' more accessible, any ready (or part) made system is by definition not a 'DIY sustainer' ! Well...one man's Ikea is another's DIY. The issues of installing and rewiring alone is enough to qualify for DIY, IMHO even with a commercial system. Some would say that anything short of designing and building something without help is not really DIY, but that kind of makes things like this thread a little of a nonsense. As I see it, many are capable of installing and making valuable contributions but lack skills and in some areas, even the materials to successfully complete the project. I don't know anyone who would consider Ikea to be DIY... maybe DIY interior design... but not DIY furniture making The issues of wiring and installation exist with all the commercial units - unless you buy a full sustainer guitar. IMO people who can't solder a simple circuit together won't be able to do this project - they should buy a ready made 'install it yourself' system - mind you, if they can't build a fetzer/ruby, they really need to get someone else to do their installation as well! For all the others who found this thread because they were looking for information about how to build a sustainer, the problems that I listed still exist, and providing a ready made circuit and driver doesn't address any of them. As I stated, I think it is possible to solve many of these problems, but it isn't easy Here's a little dialog to highlight my point: Jim: "hey, I wanna build a sustainer for myself - I've seen that their are commercial systems that I could install myself, but I really like to build guitar gadgets for myself" Pete: "thats great, you came to the right place!" Jim: "so where do I start - how do I make a sustainer?" Pete: "all you need to do is buy one of my commercial systems that you can install yourself!" Jim: "huh?" Btw, that was a very interesting gotcha about the earthed pickup poles. I suppose it would be OK as long as they are insulated effectively from the strings, although that adds some extra issues about aesthetics and installation complexity. About the lack of response in 'full' harmonic mode. I've had some problems with that as well. I wonder if the problem is that the circuits and drivers are getting good enough so that they can drive the pitch right up beyond the working bandwitch of the guitar amps... or above our hearing range... ? or maybe just beyond the frequency that the strings can effectively(for our purposes) vibrate at ?... maybe some sort of low pass filter might help to limit the top frequency of the drive signal ?....hmmm I guess it will need more thought. It is certainly an important thing to understand. As far as a variable output cap, one thing to try (it might not work because of phase response... not sure) is to have a big (200uf)cap wired in series with a pot, then have a small cap(10uf) wired parallel to them... so when the pot is at 0 resistance, the capacitance is 200 + 10, while when the pot is at max - depending on the pot value - the capacitance will be much closer to 10uf... certainly would be fairly simple to test. although I feel that the cutoff is way too gentle for a really useful change in effect - it would probably make more sense from the users point of view to have a 3 way switch with small medium and large caps... maybe even just small and large... Edit: yep, a 200ohm pot (or as close to that value as possible, set as a variable resistor) in series with a 220uf cap, and put a 10uf cap in parallel with those Then swap that for your existing output cap. That will get you roughly what you want - it will range from what you would get with a 230u cap to what you would get with roughly a 10u cap cheers Col Edited February 8, 2008 by col Link to comment Share on other sites More sharing options...
utopian isotope Posted February 8, 2008 Report Share Posted February 8, 2008 (edited) Did some mind(less)storming again after reading previous posts. Especially that "violinish" tone and sustain -thing. When I saw Led Zeppelin's "song remains the same" -live long time ago, I thought: "wow I want that bow!". And so I bought me one. Tried it with both electric and acoustic, and got quite cello-like sounds at lower strings. Higher strings gave more screeching. --------------------- What I'm after, is that when you listen to real cello sound, when bowed at lower strings, it doesn't sound nowhere as clean as guitar or bass (with clean tones). Reason why I stress those lower strings, is that it is more noticeable(at least for my ears), since cello is like slow-motion version of violin. ---------------- On guitar or bass, you pluck the strings, instead of rubbing them with a bow, letting them to vibrate freely, so that they produce sine wave without too much overtones, when compared to bowing. If we look free string vibration as a sine wave, bowing kind of "limits" strings natural movement, thus cutting its sine wave. As we know, cutting sine wave causes clipping ---> distortion ---->overtones. That's why I came to conclusion, that instead of hunting too clean sound and feedback, more overtones should be added. "Natural harmonic distortion" seems to be a major part of that desired tone. ---------------------------- As I've read these postings, distortion or fuzz/fizz seems to be the problem on the sustainer-circuit(s). Maybe it is just pure nature of tone and feedback, that tries to push out, in form of fuzz/fizz? ----------------------- If possible, get yourself a violin bow(some rosin also) and test things. Compare sounds between bowed and plucked note, so you'll see(hear) what I mean. Edited February 8, 2008 by utopian isotope Link to comment Share on other sites More sharing options...
col Posted February 8, 2008 Report Share Posted February 8, 2008 (edited) That's why I came to conclusion, that instead of hunting too clean sound and feedback, more overtones should be added. Hmm, yes, more overtones for a more realistic loud amp sound would be good, but fuzzy interference noise isn't the way to get that result IMO "Natural harmonic distortion" seems to be a major part of that desired tone. ---------------------------- As I've read these postings, distortion or fuzz/fizz seems to be the problem on the sustainer-circuit(s). Maybe it is just pure nature of tone and feedback, that tries to push out, in form of fuzz/fizz? ----------------------- Nope, the fizz/fuzz we are talking about is coming form distortions in the drive signal that are being 'heard' by the pickup due to EMI (electro magnetic interference). What you are driving at is a valid point - the fact that the timbré of a guitars sound changes when there is feedback. However, there is no reason why we shouldn't get this effect from an electo-magnetic sustainer without grunge, fuzz or fizz. That singing full sound of a guitar that you get with a valve amp up loud - it doesn't need a lot of crunch, its more about volume and a good axe (and a good player of course). One of the limitations of my circuit (the last one that was 'released') is that its maximum drive is not enough to get that singing kind of effect... it can produce reasonable loud sustain and provides lots of new creative possibilities, but it is by no means ideal. I have some other design ideas on the drawing board, so maybe at some point I'll get some new circuit posted with clips... right now, I'm more concerned about the driver side of things. If possible, get yourself a violin bow(some rosin also) and test things. Compare sounds between bowed and plucked note, so you'll see(hear) what I mean. I have a pretty good understanding of what happens with a bowed string - how it sounds, and a basic understanding of the physics (one of my other interests is digital signal processing, and I have read some papers on modeling a bowed string digitally. The math is heavy, but there are good explanations of what's happening when a string gets bowed.... and it has very little in common with soft or hard clipped fuzz...) I have a sneaking suspicion though that there is a little more to the fuzz issue. My approach (the first one to be proven to work) to eliminating grunge/fizz/fuzz completely has been to ensure that there is minimal distortion in the drive signal, this means that the EMI can still be there, but you won't hear it because it is the same signal (or close enough)... basically it is masked by the desired 'correct' sound from the string vibrations. Pete has often talked about the AGC driven sound not being loud enough. I have disagreed, because I know it is loud and the strings can be driven hard. So why doesn't it sound that way to Pete? Maybe because the sound isn't as rich, its loud, but the overtones that make it sound loud are missing! It's possible or even likely that driving the string with a heavily clipped wave changes not only the level of audible unwanted interference noise (that we don't want), but also the richness of the string vibrations and resulting guitar tone. So if thats true, How do we throw the bathwater out without losing the baby ? hmm, I have one or two ideas about a possible improvement to the 'loop' squeal canceling thing that might help... but other than that, I'm stuck for now. cheers Col Edited February 8, 2008 by col Link to comment Share on other sites More sharing options...
utopian isotope Posted February 8, 2008 Report Share Posted February 8, 2008 (edited) "I have a pretty good understanding of what happens with a bowed string - how it sounds, and a basic understanding of the physics (one of my other interests is digital signal processing, and I have read some papers on modeling a bowed string digitally. The math is heavy, but there are good explanations of what's happening when a string gets bowed.... and it has very little in common with soft or hard clipped fuzz...)". ----------------------------------------------------- Mathematics is something I don't understand, but hearing and seeing is what I understand better. And no, I'm not talking about modern fuzz or distortion. What I mean is "natural harmonic distortion", that has been over 200-300 years, maybe more, since stringed and bowed instruments were developed. If you bow an E and A strings simultaneously, you will get totally different sound, compared to plucking; almost like a choir of those two strings; no clean tone is available there. Simply too much overtones for that purpose. -------------------- No oscilloscopes are available for me, so I just listen sounds. --------------------------- Addition to that loop-thing: Aluminum isn't too good solution, because wires can't be soldered to it. Copper or brass suits better. I'm going to make new loop out of thin copper plate, to make it more reliable. Edited February 8, 2008 by utopian isotope Link to comment Share on other sites More sharing options...
col Posted February 8, 2008 Report Share Posted February 8, 2008 If you bow E and A strings simultaneously, you will get totally different sound, compared to plucking; almost like a choir of those two strings; no clean tone is available there. Nah, If I bow E and A strings, I'll just get a horrible scraping fingernails on a blackboard sound... but maybe with some practice... But seriously, it certainly doesn't sound like a 'clean' tone on an electric guitar (which in turn doesn't sound at all like a sine wave). It does have a harmonically rich tone as does a distorted guitar but I would describe the sound more as a resonant sound than a distorted[as in clipped] one. A distorted guitar sound is similar to a square or pulse wave, while a bowed string has more in common with a saw wave (most subtractive synth 'string' sounds are based on unison saw waves) If we can somehow remove the interference noise from the system while still allowing 'distorted' drive signals, it would also be possible to experiment with using various wave patterns and harmonic overtones as drive signals to try and change the timbré of the sustained guitar sound. If you are really interested in going for a sound that is not a traditional guitar sound, then maybe you should try using a piezo pickup with your sustainer... that way, there will be no trouble with EMI, and you can try all sorts of different drive signals without worrying about interference noise or squeal. cheers Col Link to comment Share on other sites More sharing options...
utopian isotope Posted February 8, 2008 Report Share Posted February 8, 2008 (edited) Yep, I have tried piezo, but it doesn't have the same "body" as (in my case P-90). Instead I got some awful howling out of it, when testing. It doesn't create as much low frequency feedback(without preamp), as magnetic pickup does, that is needed for strings and guitar body to vibrate. Maybe enough for an acoustic, but not for solid body. ----------------- Flash from the past: some 15 years ago I struggled with feedback, after listening Jimi, "how can I get that sound". So I took speaker, mounted it in back of my guitar, and hooked it in stereo amp. "More low frequencies", I said. Finally I got some feedback, till that speaker started to smoke. End of the story. ----------------------- But all in all we are closer to those sounds than ever before, if commercial things aren't counted. Edited February 8, 2008 by utopian isotope Link to comment Share on other sites More sharing options...
psw Posted February 8, 2008 Author Report Share Posted February 8, 2008 hehehehe...my daughter plays violin pretty well, but years ago I tried the same thing...for much the same reasons. Guitar strings make a mess of a bow BTW, so I won't be doing this with my girl's...however...after sitting through hours of screeching, bowing technique and angle are all important to getting the range of timbres that you describe and the guitar is not set up for such playing. The angle to the strings and the angle of the bow hair plus touch and everything greatly effects the sound...it is amazingly expressive from "distortion like" to pure tones...when you get good at it. One of the problems with the whole digital thing, even sampling...is that it only captures a little of the organic approach of the original technique. One of the attractions of the sustainer over similar digital possibilities is also this real time organic technique. Yes you are right col that this is a difficult project which, even if supplied in a kit form or complete system...even the available systems...are difficult to successfully install and does take some skills. However, your "conversation description is a little ingenuous I feel...after all, I have sought to make this as approachable as possible for people to explore and enjoy the technology. What I am proposing is an option that can only enhance the DIY and development side as far as I can see. If someone wants to build it themselves, but the coil winding side of it is daunting (the most usual response from talented stompbox builders and such), then here is a way that you can get a working and superior coil pre-built. If people have their own driver ideas, then fine, maybe you want to get the circuit and get right down to it. Look at the situation with utopian isotope, here a module is being used with a stompbox eq as preamp and a fairly crude coil. Now, the loop is interesting but it is very hard to tell if it is working to compensate for the radically different amplifier, the high battery drain and under powering of the circuit or what is going on. With a more suitable circuit, even a F/R, would it still require this loop for the same or better performance...very hard to tell. So...I don't feel that I am really proposing to offer something like the sustainiac or fernandes products, unless that is what you want...and certainly I don't think jim would be disappointed by the options offered from this thread and enhanced by ready made components to make it easier. By far the majority of work is preoccupied with installation as each application has it's own problems. These can only be discovered by attempting to do real installs it would seem, and to that extent, I am doing a tremendous amount of work in an effort to sort out some solutions whether build it yourself, design it yourself or simply installing it yourself. enough of this "issue" however! ------------------- Pete has often talked about the AGC driven sound not being loud enough. I have disagreed, because I know it is loud and the strings can be driven hard. So why doesn't it sound that way to Pete? Maybe because the sound isn't as rich, its loud, but the overtones that make it sound loud are missing! Well...in part I am responding to your own circuit and sound clips...compared to the non-AGC circuits like my own... One of the limitations of my circuit (the last one that was 'released') is that its maximum drive is not enough to get that singing kind of effect... it can produce reasonable loud sustain and provides lots of new creative possibilities, but it is by no means ideal. My version does this, which I was under the impression you had aimed for, at lower settings....while retaining the overtones at higher settings. The fizz at more controlled settings is hardly there, and not at all on low settings. There is the distortion of overtones when driven hard, but that was what I was trying to say...that the singing sustain is intrinsically "distorted"....but not by fizz! The caveat to this is the harmonic settings...and the transition into harmonics, where there can be some "fizz' in that period of transition. So, it would appear that phase is a factor in the "fizz" perhaps. The idea of using filters to create different responses is in a hope of avoiding the whole reversing of the drive signal by creating harmonic and perhaps a broader range of responses, without the reversing of the wires. The nature of the phase switch harmonic thing is that the device is suppressing fundamentals, there is therefore a drop in the level just as playing harmonics on a clean guitar are softer. An EVH harmonically rich sound compensates greatly...a wha on the signal will bring them out...often sustain is there, but the strings are vibrating so high and fast that the amp has trouble bringing these sounds out and, the circuit has trouble driving at these frequencies...and at these harmonics, the physical swing of the string is much less, so are creating less signal in the sensing pickup too! I find the bloom into harmonics to be far more attractive than the sound of pick attack, followed with a little delay by the harmonic taking hold...rather I would like a response where in the sound quickly morphs from fundamental to harmonic. With my mild and simple AGC, I am getting the singing sustain...and on the last night's install (sat morning here), I am getting this with the minimum of gain on the LM386. This is a good thing in that it means that it is using far less power for the same effect...however it makes the amount of different effects from the drive knob a lot less, to the point of questioning it's relevance. Even with it's small amount of travel though, it can move between a harmonic rich overdriven loud sound (not fizzy) to a clean infinite sustain. A dp rotary could provide a range of gain and harmonic settings and seems to have some appeal, at least to me... I am hoping that in the near future, and with the hidden resources of this web site, I will be able to make this clearer by posting audio and video of the thing in action. Not only can the potential be illustrated in this way with "successful" installations and designs...but so too can the failures that will better illustrate what is fizz/fuzz/EMI and what is an attractive "loud" overtone sound. There seems to be a lot of misunderstanding of what each of us are able or have achieved and which attributes we are seeking to enhance and problems trying to address. Other than audio posting or repeating eachothers work for ourselves, I am not sure of a way to adequately address this. ok...BTW...I found an interesting circuit last night col (off-line) that is an all pass filter that adjusts phase to frequency while keeping a constant level...simple op-amp design, but something I have never seen before. Might very well have application for phase compensation circuitry or enhanced control. Will try and find a way to send or post this soon. for now...I will be trying to shore up the working version for best performance and playability then swapping out the driver for the new version and trying to add more pickups into the mix without compromising the performance. Along the way, some of my newer installation schemes will be verified, so I will be posting them also...as time permits. later pete Link to comment Share on other sites More sharing options...
col Posted February 8, 2008 Report Share Posted February 8, 2008 ok...BTW...I found an interesting circuit last night col (off-line) that is an all pass filter that adjusts phase to frequency while keeping a constant level...simple op-amp design, but something I have never seen before. Might very well have application for phase compensation circuitry or enhanced control. Will try and find a way to send or post this soon. later pete You need to pay attention in class boy... hehe, One of my harmonic modes IS an all-pass filter - I explained it in detail ages ago - it is definitely a useful module for us to use, but it's important to also understand it's limitations. Anyway, there's no need to worry about sending it to me. ======================================= Here's something I discovered a while ago that you should have a think about as it will have an impact on your 'piggy-back' system. I only just realized the connection or I would have posted about it a while back... As you know I've been trying to come up with a way of measuring the inductance of coils. Part of that has involved making coils and trying out proposed measuring techniques from books and the net. I haven't been able to verify the accuracy of any single measurements yet, so haven't posted anything, but one thing I have been able to do is get a rough idea of the relative strength of different cores. One significant thing I have discovered is that if you add some core material to the core, it has an effect even if it is not within the coil... say you have a driver with the core protruding a few mm from the bottom - if you stick some more iron to that, even though it is further away from the coil, it can still have a significant impact - as in 30 or 40% more inductance... So how does this affect your system? Well, if your driver is using an existing core from an existing pickup, the performance of the driver - drive strength and frequency response - will depend to some extent (more than you may realize) on the specifications of the pickups core! The effect it has on the frequency response should be somewhat reduced by the fact that you have an impedance that is mostly resistive due to the thin wire with fewer turns. However, the difference between one pickup core and another could be enough to cause the system to function poorly on some guitars.... I don't think this will be a killer problem, its just something to be careful about - test as many types of pickup as possible (I'm sure you're doing that anyway)... One way to think about it is that having a core with twice the inductance factor (a realistic possibility) would have roughly the same impact as going up to the next wire gauge (assuming you were to stick to 8ohm resistance)!, and you know through experience how that can effect the functionality. With any luck, there is some sort of rough 'standard' for pickups, in which case you would only have to worry about the extremes like 'The Invader' at one end.. or some weedy retro copy type of things at the other... If you can borrow an inductance meter from somewhere, you should test the inductance of one of your piggyback coils without a core, then again when mounted on different pickups - this will give you a much better idea if this is something you should be concerned about. If you find that some pickups can give readings 60% or more greater than others, you should take it seriously as a potential problem. cheers Col Link to comment Share on other sites More sharing options...
psw Posted February 9, 2008 Author Report Share Posted February 9, 2008 hehe, One of my harmonic modes IS an all-pass filter well electronics, like my fakoid spanish...is not really a language I understand too well...I know enough to ask directions but not enough to understand where to go when told.... Actually....I was thinking of the circuit as a means to address phase correction and/or harmonic control. It would appear to me (taking the above statement into consideration) that the output cap has an effect on phase angle of the drive signal...thus different responses in harmonics results. Your statement in another post that a 1000uF cap would perhaps be advantageous (with high power, etc) was puzzling as, increasing the cap value appears to increase the bass response. As far as I can tell a 220uF is enough to drive the low strings...on my bass experiment...I used a 470uF and I think that that may have been too low even on that. My 100uF compromise was to bring out the mixed mode and give a good strong response on the high strings and a little more balance to chords. Perhaps in harmonic mode, the phase switch needs to incorporate a cap to bring the ultra high frequencies back down or filter the driver signal of super high fizzy signals and clashing upper harmonics...hmmm So how does this affect your system? Well, if your driver is using an existing core from an existing pickup, the performance of the driver - drive strength and frequency response - will depend to some extent (more than you may realize) on the specifications of the pickups core! The effect it has on the frequency response should be somewhat reduced by the fact that you have an impedance that is mostly resistive due to the thin wire with fewer turns. However, the difference between one pickup core and another could be enough to cause the system to function poorly on some guitars.... Yes...well it is of a concern and some pickups dimension wise will not work...my present coils only fit strat sized pickups...hence in part my concern for effective multi-pickup installation switching... Recent "problems" with cheap pickups are a little mysterious..I don't think this is related... I have tried a few different pickups, the present one is typical alnico magnetic poles...but slugs with a ceramic magnet below and models like the noiseless with central magnets also seem to have similar performance. Some of my coils have been as low as 7.2 ohms and seem to still work effectively too. Ideally, I want to achieve greater consistency of course, but 8 ohms is the value favored by the LM386 amp for maximum power. However it will work within a range of 4-16 I believe. Again, not a lot of difference in performance from like quality and specifications (size and coil depth, potting and construction....same pickup/core). Measuring it now, fitted in the guitar, it would seem the coil in the present working model is 7.6 ohms (digital multimeter). Besides less power, what other effects could one expect from a lower coil resistance? By my theories of course, less phase difference/"faster" coil... On this guitar which runs on the lowest possible settings and with a reduced range of effect, perhaps it could do with a little energy reduction. It is a little encouraging then in light of my most recent bi-direction coil where some of the outer layers are given over to a reverse winding for magnetic shielding, that a coil of perhaps 6 ohms around a core would still work...of course it is a gamble that may not pay off! If you can borrow an inductance meter from somewhere, you should test the inductance of one of your piggyback coils without a core, then again when mounted on different pickups - this will give you a much better idea if this is something you should be concerned about. If you find that some pickups can give readings 60% or more greater than others, you should take it seriously as a potential problem. Hmmm....I am not sure that I can borrow one. Is inductance also measured by frequency also, does not inductance also vary with the frequency of the signal going through it. I know there is some standard (1000Hz or something) but it may well be worth testing the coil at it's operating frequencies too. I am not sure that an inductance meter can do this. Can you explain or link to an inductance meter somewhere....are we talking about a huge investment....will it offer other features or this enough to make having one worthwhile to myself and others here? If you can borrow an inductance meter from somewhere, you should test the inductance of one of your piggyback coils without a core, then again when mounted on different pickups - this will give you a much better idea if this is something you should be concerned about. If you find that some pickups can give readings 60% or more greater than others, you should take it seriously as a potential problem. An option that would certainly make it easier on me is to provide pre-modified pickups with the driver mounted permanently. This would take some of the quality/aesthetic burden from me and give ultimate consistency....plus an extra layer of simplicity to building the system. Of course it also undermines some of the appeal; pickup choice...but hey! I have come across some good quality cheap-ish pickups that would work...especially if aimed directly at strat type guitars for instance. As a side note, I did notice that after building the original pickup/driver that the quality of the pickup's sound seemed to greatly improve. With the middle pickup identical but unmodified...the act of inserting a 10mmx3mm solid steel blade in place of very small "screw" like poles seemed to greatly improve it's sound (more body or something) and was available for direct comparison. It makes one wonder if such strategies could not be performed on similar constructed pickups to also gain performance...obviously relating to the issues raised of different cores adding to inductance. Also, in the kinman designs, and some others it would seem, the lower noise canceling coil can be made smaller and wound with alternative wire with additional mass inserted in the lower coil...or so it seems. Kinmans have additional lower slugs at the coil ends and others like the fender noiseless are wound on two part bobbins attached via screws, again adding mass. It is an area that I have often thought I'd like to explore...and to do so "scientifically"...I guess an inductance meter may also be in order. I have also had a desire to include aluminium into pickup designs...would such materials add to inductance even though not magnetic, they can harbor eddy currents through their conductivity. Similarly neodyminium magnets...I had a design mapped out and someway towards constructed that used ball bearings in the poles with neodyminium magnets attached and some machine bolts that could be screwed to adjust the mass of the internal core. I am imagining for these kinds of things, that inductance is only a small part of the equation and that frequency response and resonances are more of an issue... While sympathetic and still working on the "best driver" approach, I am also working on balancing priorities (retaining the pickups) and compromising (less mods and ease of installation) and standardizing (one size fits all). If a design has promise while retaining these things, I am bound to pursue it. My bi-directional design, although quite possibly not going to be so effective...still retains all of the qualities of the "normal" design and application. A bi-lateral design has none of these qualities and so must replace or sit beside a pickup...not within my present scope of experimentation. Somewhere in the back of my mind though, there has always been a hope that a signal could be sent into the pickup coils to cancel noise and fizz caused by EMI and perhaps counteract forces that require such elaborate switching. For the ultimate in fizz, you can't go by something like this early design of mine... How this idea would work now I am not sure...in those days I tried to fit the things without modifications, so that even if deselected the ground was always shared, something that was only rectified once I began installing devices into real instruments... A better incarnation was this design from the hex era... built at the same time with similar technology... This shows there are many ways to skin this cat and to approach a better mousetrap; it also shows the early genesis of the piggyback approach and the reduction in driver size to limit EMI that carried over to the more conventional thin driver concepts with more conventional coils for DIY construction. These did work BTW...in their own fashion...however practicality and bizarre quirks (an example and clue for col and others is that alignment was important and that with some HEX designs bending strings caused harmonic mode to sound in one direction, bent the other way, increased power and fundamental sustain) that seemed to want it pushed to the ends of the string (at the bridge) and just too close to the pickup...eventually it meant that a change in direction was needed...I rarely look back to these designs (preoccupied me for a year) but still retain some affection for them and they did and still retain some mysterious behavior...ultimately probably not the best of designs, practically speaking, but the principles and results did show a great reduction in EMI. Now I must go build a sustainer...some more...and tidy the house...etc... pete Link to comment Share on other sites More sharing options...
psw Posted February 9, 2008 Author Report Share Posted February 9, 2008 Ok...to lighten things up a bit...check this out... I'm watching tv and playing the sustainer guitar. I think I mentioned that the test guitar has it's pickups mounted with double sided tape...this is true, but this is to little squares of plywood that fit into the generous full strat pickup rout. These are held in by modeling clay (plasticine we call it)...so it is not too secure and occasionally pop out while playing (still an easy quick mounting procedure and allows for easy height adjustment and removal and...ok, I didn't screw them in...) So here I am playing, and as I mentioned...sometimes the neck pickup will come loose, stick to the strings and the guitar give off a shriek. This time, I look down and the pickup has moved close but not touching and there are sparks coming off the g string to the pickup pole (or visa versa)...there must be a lot of energy in this device despite running off a half flat 9volt battery!!!! Another reason not to use wall adapters perhaps... Although there were fireworks, there was no shock and the device continued to work flawlessly without noise associated with the effect that I repeated a few times. This is not a normal feature but shear accident...however I imagine it could happen with anyone's device. I have experienced mild heating of the coil before, however I assumed that some of this was to do with slight movement in the windings and felt that this was confirmed by the lack of particular warmth with the epoxy potted coils of this design (these coils are not only solidly potted but condensed under pressure to remove any air gaps)... It would be mega cool if this "effect" could be a feature...no need for LED's if it is going to do that... Just thought I'd share...not a lot of work done, perhaps tomorrow...one thing about having the guitar working again is that every time I go to do something on it, I have one last play that lasts half an hour and then find an excuse to do something else rather than mess with it...these things are a lot of fun... pete Link to comment Share on other sites More sharing options...
The-Stratomaster Posted February 9, 2008 Report Share Posted February 9, 2008 for those who said you would ahve to rip a pup out, how about (if a strat) put on a hss puickguard and only use a single coil with the sustainer beside it Link to comment Share on other sites More sharing options...
col Posted February 9, 2008 Report Share Posted February 9, 2008 hehe, One of my harmonic modes IS an all-pass filter Actually....I was thinking of the circuit as a means to address phase correction and/or harmonic control. It would appear to me (taking the above statement into consideration) that the output cap has an effect on phase angle of the drive signal...thus different responses in harmonics results. Yes, thats one of the uses of all-pass filters, phase adjustments. You have to remember though, that an all pass filter can only give a specific desired phase adjustment at one frequency - so if you want to 'correct' phase you will need a higher order all-pass filter (like lots of simple ones together), and the circuitry starts getting ridiculous. Yes, the output cap has a phase response - many components do. It is useful to think of the whole circuit including the output cap (and maybe the driver) as having an overall phase response. This overall response changes when you alter the circuit, changing component values, adding or removing components can alter the phase response. This can have a big impact on the success (or failure) of a sustainer system - particularly in the case of the 180º phase harmonic mode, I might post some more details about that later. Your statement in another post that a 1000uF cap would perhaps be advantageous (with high power, etc) was puzzling as, increasing the cap value appears to increase the bass response. As far as I can tell a 220uF is enough to drive the low strings...on my bass experiment...I used a 470uF and I think that that may have been too low even on that. I said "output cap on circuit causing distortion in low frequency signals (to avoid this completely we'd need a 1000u cap!)" This is true - with a cap smaller than that there will be some altering of the signal because the cap will restrict the fundamental frequency and cause some phase distortion. I didn't state that we must use a 1000 cap, just that anything smaller will not allow the pure signal through at low frequencies. It seems that you like the effect caused by a smaller cap anyway, so there's no need to worry Additionally, the audibility of this effect depends on the phase response of the rest of the system. e.g. I have a 220 output cap. with my dual core driver, I get true fundamental sustain right down to the low E with my single core driver (everything else the same) I get mixed mode on the lower notes... this will be due to the driver having a different phase response and changing the overall phase response of the system at those low frequencies. The output cap is just one part of the equation. Besides less power, what other effects could one expect from a lower coil resistance? By my theories of course, less phase difference/"faster" coil... On this guitar which runs on the lowest possible settings and with a reduced range of effect, perhaps it could do with a little energy reduction. I think coil resistance is less important than inductance as long as you stay within a reasonable range. Too high a resistance and you will lose too much energy through heat in the coil. Too low a resistance and the battery wont be able to supply enough current (and the LM386 would fry anyway) so as long as you stay within the 4ohm - 16ohm impedance range, you don't have to worry too much.... the difference between 6 ohm and 10 ohm will I think be less than the impact of a similar change in the inductance due to number of coil turns or the core properties (or both) Hmmm....I am not sure that I can borrow one. Is inductance also measured by frequency also, does not inductance also vary with the frequency of the signal going through it. I know there is some standard (1000Hz or something) but it may well be worth testing the coil at it's operating frequencies too. I am not sure that an inductance meter can do this. Inductance does not change with frequency, however measuring inductance accurately is very difficult a low frequencies which makes good accurate meters more expensive. Can you explain or link to an inductance meter somewhere....are we talking about a huge investment....will it offer other features or this enough to make having one worthwhile to myself and others here? I'm no expert in this area - I haven't got an inductance meter(yet). There are lots of options, from fairly cheap DMMs with an intuctance feature... maybe £30 - £50... to better dedicated LCR meters at £80-£120 and then you have professional stuff at hundreds or even thousands of pounds !!! I know that the cheap DMM meters use a fairly low frequency and simple method, and that there accuracy is not great, but the biggest question is probably the range.. and at this stage, I'm not sure what range we need... are we talking mili Henries, micro Henries... I dunno. If the cheap option can measure the range that the coils we are making fall within, then they will probably be good enough - I don't thing a +-5% accuracy is going to be a big issue for us Here is a DMM that has inductance - zoom in on the picture, and look to the upper left portion of the selector switch - that section marked H is the important section (other meters might have L for inductance instead of H for Henries). This meters smallest scale is 2 milli Henries - is that small enough for us? I dunno. This is a dedicate LCR meter at twice the price of the DMM - it goes right down to less than 10 micro Henries ! and the accuracy is way better. An option that would certainly make it easier on me is to provide pre-modified pickups with the driver mounted permanently. This would take some of the quality/aesthetic burden from me and give ultimate consistency....plus an extra layer of simplicity to building the system. Of course it also undermines some of the appeal; pickup choice...but hey! Yes, that would certainly help - but that makes it even less DIY... and besides, you still have the phase response of the pickup (the bridge pickup that is) to consider! that will also have an impact on the overall phase response of the sustainer system... feck me, it never rains but it pours! lol enough to drive you insane innit. Also, in the kinman designs, and some others it would seem, the lower noise canceling coil can be made smaller and wound with alternative wire with additional mass inserted in the lower coil...or so it seems. Kinmans have additional lower slugs at the coil ends and others like the fender noiseless are wound on two part bobbins attached via screws, again adding mass. The kinmans are designed to cancel electrical noise - so the humbucking coil section must collect an equal magnitude and range of noise, while at the same time having as small an impact on the magnetic side of things as possible, so fewer turns of thicker wire to give a much lower inductance and a much lower resistance, but still working well as an aerial to collect that electrical noise. Thats no good for us though - we're not worried about electrical noise, it's magnetic radiation thats killing us, so if we were trying to cancel our problem using coils, we would need to somehow make the strength of the field generated by the EMIbucking coil match that of the main coil.... using fewer turns of thicker wire will not work! But using enough turns to match the field magnitude will kill efficiency because it will also cancel the drive field... Thats why utopian isotopes idea is so promising - it potentially solves that quandary! by moving the cancellation coil over to the pickup, the field strength can be equal at the pickup due to proximity, but have very little impact on the driver because it is a much smaller coil.. I think the idea needs a lot of work and refinement, but it has a lot going for it. It is an area that I have often thought I'd like to explore...and to do so "scientifically"...I guess an inductance meter may also be in order. I have also had a desire to include aluminium into pickup designs...would such materials add to inductance even though not magnetic, they can harbor eddy currents through their conductivity. Similarly neodyminium magnets...I had a design mapped out and someway towards constructed that used ball bearings in the poles with neodyminium magnets attached and some machine bolts that could be screwed to adjust the mass of the internal core. I am imagining for these kinds of things, that inductance is only a small part of the equation and that frequency response and resonances are more of an issue... I don't think aluminium or neodymiums will have a big impact on the inductance, but they won't have a big impact on frequency response or resonance either! Anything that does change the inductance will change frequency response, resonance characteristics and phase response because they are dependent on the Inductance. Inductance is probably more important that any other single electro magnetic concept for this project - at least in terms of understanding why things work (or don't) the way they do... understanding what parts of the construction of a driver or pickup have an effect on the inductance, and how the inductance is linked to the phase response, the amplitude response and the field strength... magnetic field strengthSomewhere in the back of my mind though, there has always been a hope that a signal could be sent into the pickup coils to cancel noise and fizz caused by EMI and perhaps counteract forces that require such elaborate switching. I have wondered in the past about using some sort of negative feedback(or feedforward?) 'error correction' to limit the fuzz, which is similar to what you are talking about... A cancellation signal would have to be buffered, and it would most likely only have to be small, but if it doesn't have the same phase shifts that the driver and pickup have imparted on the noise we are trying to cancel, then it just won't work. Additionally, if any of the noise is caused by clipping due to interaction between pickup and driver, this approach will not work. (utopian isotopes loop idea might still be able to help with the driver/pickup transformer clipping noise because it has the potential to create an opposite transformer clipping effect ) cheers Col Link to comment Share on other sites More sharing options...
psw Posted February 9, 2008 Author Report Share Posted February 9, 2008 Welcome The-Stratomaster for those who said you would ahve to rip a pup out, how about (if a strat) put on a hss pickguard and only use a single coil with the sustainer beside it I am not sure what you mean. Some people have dedicated drivers that replace the neck pickup...I favor building the driver onto a neck pickup...so there is no loss of pickup when the sustainer is off. Whatever...you do realize that the sustainer can only work with the bridge pickup and extensive bypassing is necessary and possibly problematic. So...I am not quite sure what you mean by this post... Col...very late here, so will look into it tomorrow... I am very interested to know what components effect phase and how this can be "adjusted". With a 220uF cap I get very good normal low string sustain, but then the high strings really struggle. The 100uF is a compromise. On the present guitar, it may be a little low as the harmonic mode, the bass strings only get the kind of response I'd expect...on the sustainer-strat, the high string harmonics are very strong....hmmm My idea is to some how provide a range of responses. Often there are some notes that are particularly resonant. On this guitar, I am getting some amazing effects. The note D on the b string is terrificly strong and tends to ring in a harmonic at higher gain, the d string has an amazingly high harmonic bloom that I have never achieved like this before, with the same circuit. Obviously the guitar and pickups makes a fair bit of difference. These kinds of things makes the thing special to me...I know some would want a more predictive response on all strings but I learn to make good effect by playing notes on different strings for different effects. What would be cool is if a range of responses can be brought forth. Obviously the commercial units use phase compensation to tame the response by adjusting phase with frequency...but to me it would be cooler to be able to manually adjust this response. I think that such a device is more effective than a simple harmonic switch. So...is there a way to rotate the signal 180 degrees or there abouts without using the phase switch or op-amps....simple filters and capacitor changes. My feeling is that the crude 180 degree reverse is a little much. As the phase differences are more apparent with higher frequencies (part of the reason it is hard to drive the high strings), at harmonic frequencies, on this new install, I get actual damping I suspect...not good. On the lower strings, very high harmonics...mainly the low e...but on the higher strings the frequencies are just way too high to be useful. I have consistently tried to simplify the circuit and look for driver efficiency to address these problems of phase...and with some success. This is the reason for aiming for a "fast" driver that can work without such phase cancellation. Now, I am having trouble with the harmonics...hmmm...perhaps some more targeted or variable phase angles are required. Hey...that reminds me, that I have been able to get two tones on this d string...both the fundamental and the very high harmonic with finger vibrato...very nice. Another symptom is a slightly annoying harmonic "ring" to the note just after plucking...not really a distortion, certainly not fizz...but as if the driver action is anticipating the harmonic before settling into the fundamental. Less power cures it, so perhaps I need to back it off a lot more...but a little strange. Otherwise...a little late, so will read the post again and check out those links. It would seem that an inductance meter is not really something I need so much at this point and with a driver design that is so variable with the pickup it is fitted to. Perhaps more pertinent would be some kind of frequency response or way of measuring phase angle....maybe a software oscilloscope (and knowing how to use one) and a frequency generator or something. For now, it is trial and error, but if I were able to incorporate more variations, then each would have their appeal for different instruments and driver responses. will be back later, but after midnight and brain gone to mush...thanks for the post though col...hopefully test the new coil tomorrow/today...I have drawn up a new layout that spaces the present circuit out and my intention is to set it up so that various critical components can be switched out while still in the guitar so I can get some real time "feedback" on the effects of different values on the circuitry. I am preferring to steer away from trim pots and other "complications" in design pete Link to comment Share on other sites More sharing options...
ghendrickson04 Posted February 9, 2008 Report Share Posted February 9, 2008 Hey all. After about 6 months of watching from the sidelines (school keeps me busy), I'm finally ready to join the party! Just a quick question: I've already wound a coil, but what pre/amp should I use? I see a lot of talk about starting with a Fetzer-Ruby, but I recall that, not too long after I started following this, col posted a circuit he made with AGC and using a 3p4t rotary switch. What would be a good place to get started? -Garrett Link to comment Share on other sites More sharing options...
disndat Posted February 10, 2008 Report Share Posted February 10, 2008 Hey guys I have a variax that I transplanted to a strat.I bought a fernandes sustainer and I use it with just the single coil driver and I drive it from the analog output of the variax(no bridge humbucker required).It works great.My question is could I use just the ruby circut and a wound driver and drive it the same way as the fernandes?I would like to simplfy things and I only need standard and harmonic modes(no use for mix mode).I would like a 3 way toggle(les paul type) to switch from off to standard to harmonic.Any thoughts?Col, Pete? Thanks for any info Link to comment Share on other sites More sharing options...
col Posted February 10, 2008 Report Share Posted February 10, 2008 Hey guys I have a variax that I transplanted to a strat.I bought a fernandes sustainer and I use it with just the single coil driver and I drive it from the analog output of the variax(no bridge humbucker required).It works great.My question is could I use just the ruby circut and a wound driver and drive it the same way as the fernandes?I would like to simplfy things and I only need standard and harmonic modes(no use for mix mode).I would like a 3 way toggle(les paul type) to switch from off to standard to harmonic.Any thoughts?Col, Pete? I would say - forget it If you already have a commercial sustainer installed and working, why would you want to go through the difficult and time consuming process of building your own? (other than for the 'thrill of the chase' in which case, get a cheapo guitar to experiment with) It is possible (although highly unlikely IMO) that a DIY system could be better than your fernandez, but one thing I can assure you is that it will not be simpler - either to install or to use ! If you want to remove one of the switches or controls form your fernandez unit, the first thing to do is get in touch with the manufacturer and ask them for advice. With any luck they will tell you which wires to connect together so you can ditch the control. good luck Col Link to comment Share on other sites More sharing options...
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