Hank McSpank Posted January 21, 2009 Report Share Posted January 21, 2009 (edited) Anyway...you are going into relatively uncharted waters with the hex thing. I wish you and donovan could explain to me why you feel it necessary to do this as you are making things far more than six times as difficult and throwing away a lot of the established research and so having to deal with it again. Ok then (& btw, I'm not throwing away anything!).... 1. Massive synergies with midi guitars (which I'm into big time!) 2. Much *much* lower power in use for the majority of real world playing scenarios (=less emi flying about)...lower power per string also means potentially less interaction of the magnetic fields between strings. I'm seeking an incredibly small tight focused electromagnetic field, with the driver very close to each string in turn....I reckon this can only be achieved with a hex solution. 3. Better 'control' per string, which in turn avoids a one size fits all approach to sustaining for example chords. A nice tight frequency band for each amp circuit (on account you're only handling one string of limited frequency band - open string to highest fret) 4 I actually need polyphony for a cunning idea I hope to exploit once I get there with a good working hex driver! The particular mono driver you've researched, may be an efficient driver & yield the required results, but when you think about it, when soloing spewing a dominant note across all the strings isn't such an efficient approach?! If a string isn't being played then why whack it with the same magnetic force as the sting that is...far better to have a much lower power focused driver only being active if the corresponding string is being played. There's certainly a beauty in the simplicity of your design (driver & circuit) & the research you've done is the best available anywhere on the web....but there's always going to some of us are going to want to head of in different directions...not to be awkward or throw away the invaluable research that's gone on here, but just to see if it's a viable concept & see what it can bring to the sustainer party. I'm not trying to reinvent the wheel...I just want to add more wheels! There doesn't appear to be a whole lot of people who've tried to get a working hex driver ...but I'm very interested in surmounting the unique problems associated with a hex driver. Thrill of the chase, I climbed it because it was there blah blah** ** Insert your own cliche to suit. Edited January 21, 2009 by Hank McSpank Link to comment Share on other sites More sharing options...
psw Posted January 21, 2009 Author Report Share Posted January 21, 2009 Yes...well as long as you realize that you appear to be climbing it because it is there and you don't really know what you will find there when you get there... Obviously, I have and had similar ideals about the hex driver...but it is not possible to ignore the interactions between the coupled magnetic fields. Obviously in an ideal world the hex thing seems to be the logical approach, my hex things had 12 magnets in them to contain the fields...but then there are all kinds of problems with string alignment. I am not sure about the rest of the ideas about EMI and coupled fields, induced currents in nearby coils and stuff. Not sure even about the less power idea either...even the moog recognizes this by having the dampening as an option...it is possible since no one has played it that it does so to get a more traditional sustain effect or something as you would wonder why you would want to turn it off it it really was everything they hype about it...hmmm...lack of any technical information only makes that thing worse and people jumping to conclusions in the last year based almost entirely on demo vids. #1 sounds like hype a bit...do you mean you have already separate string signals so you may as well use them? #2 maybe #3 possibly...with a lot of circuit and or driver design tweaking. This and improved polyphonic sustain was part of my motivation too...my approach although in the initial stages was to chain them together in alternating polarities using a balanced field that used the power of the passive magnets to work the string generally from side to side (hence alignment was critical and brought string bending into question)...but the next phase would have been to bias each driver to work best for each string... #4 see #3 AND...with a synth contoller, have you not already got sampled infinite sustain or at least infinite sample and hold sustain already without any feedback effects? when soloing spewing a dominant note across all the strings isn't such an efficient approach?! I don't understand this...it recycles the signal and the only likely string given decent damping as well that is resonant with that signal is the note or notes playing surely? far better to have a much lower power focused driver only being active if the corresponding string is being played. Perhaps...but only if the above was an unsolvable problem...which it isn't really. The reason being a driver design that can produce the required emf to do the job without excessive EMI and doing it efficiently enough. The output thing is not quite yet understood...it is unlikely that you just divide the output of the circuit by six for instance which you are assuming. Then there is the design of your driver...how are these going to be built within the space allowed...10mm...or these magnetic fields kept separate? There's certainly a beauty in the simplicity of your design (driver & circuit) & the research you've done is the best available anywhere on the web....but there's always going to some of us are going to want to head of in different directions Yes...well we have covered this....by now you will see that this is exactly why the thread is so long and varied and there is no one definitive solution and tutorial...I never claimed that there was one way or that it had anywhere reached it's potential. However, the title says DIY and the current preferred design only came about when I was accused of being a fake because all my development went into the hex thing. The point was, that as a DIY project, all the work I had done on the HEX things could hardly be duplicated by anyone and would cost an enormous amount if you tried! Hence, I built a simple solution for people to try for themselves...I then realized that the elegance of this solution was probably a better place to work from than all that I had done in a year with a lot of other benefits that I had been working towards (like a driver pickup) in an already working format and for the vast majority of guitars that don't have individual string output signals...let alone the need for six amps, etc. After all, people seem to have trouble following even the basic circuits presented here and the driver design and construction methods...or feel the need to go their own way only to discover much of what I did and had already warned about. I am only seeking to warn people who seek to do these things that I have tried a lot for similar reasons... anyway...i am sure you will find much discussion about some of these things already...is there a reason that the "cunning plan" is so secret...again, it seems like there are things that I don't appreciate in your drive towards this solution. Perhaps you could draw up some ideas for the driver designs and separation strategies? Also, be away that there could be a massive R&D cost blow out...i certainly found out this and continued way to long with enormous cost...i am actually embarrassed to admit how much I have spent on this actually.... pete Link to comment Share on other sites More sharing options...
Hank McSpank Posted January 22, 2009 Report Share Posted January 22, 2009 (edited) You're asking me to post up driver design...when at this stage, I've not even had a chance to fail miserably in the privacy of my own loft! My initial plan is to use 38 SWG wire to try and wind a single string test driver to something in the order of 40 Ohms. I'm thinking of first trying a NE5532N to drive it - I'll feed a test circuit sine wave from a signal generator & keep cranking up the amplitude (& if necessary, the circuit's VCC) to hopefulyl get a high E string stimulated sufficiently on a test rig single string guitar. I reckon if I can get each of the string just past the edge of being stimulated, then there'll hopefully be enough separation (additionally, a large part of the separation strategy comes from the fact that a driver will only be active when its corresponding string is being played) I'm envisaging that each string will possibly need a different driver characteristic (and possibly circuit!)....it's very early days, I'll probably fail - but it's not a strong enough argument *not* to try because others haven't totally nailed it. If it works...the possibilites are quite exciting. Edited January 22, 2009 by Hank McSpank Link to comment Share on other sites More sharing options...
psw Posted January 22, 2009 Author Report Share Posted January 22, 2009 oh no...i am not suggesting not to try it...just saying...well, not sure what i am saying i guess...just that I did a lot of work on it with a lot of misconceptions that took a lot of convincing by failures and half successes before I could put it to one side. In fact, such things are almost impossible to put aside and I actually tried it again last year with a bass version mounted at the bridge with the old hex design...goodness knows why, as when people ask about the bass driver thing, I often have a similar response...why would you want your bass feeding back...hahaha What would I know really...surprise us, but keep researching and experimenting with a few things... the NE5532N is an op amp, not a poweramp, it is unlikely to put out the kind of power or handle the impedance typical of driver applications...again, think of the speaker analogy perhaps but also the differences between such components as well as the drivers ability to generate the kinds of EMF required. Things like the LM386 are poweramps designed to drive speaker like loads...however there are plenty of poweramps out there, especially in SMD's. Many will be stereo and many will be optimised for perhaps 32ohm compact headphone loads. You may even wish to explore things like cheap headphones and try and salvage the coils out of them, insert cores and magnets to produce drivers...however, remember the forces required to move a light speaker cone is quite different to a guitar string under tension. Link to comment Share on other sites More sharing options...
Donovan Posted January 22, 2009 Report Share Posted January 22, 2009 Hey Hank, if you are going down the hex driver road, check out coilcraft.com. They make some power inductors that have bobbins that might be sized nicely for you. Pete, here's my update after a day in. I broke down and removed my neck pickup so I could test without holding the driver over the strings. I was also getting suspicious that taking the signal from my guitar jack might be varying the results due to the cord length, volume control, pickup selector, and tone control. So, like I said, I broke down, removed the neck pickup and replaced it with my driver, lifted both leads from my middle pickup, and split the signal off my bridge pickup. I ran both sets of leads through the small hole for the ground wire that goes to the tremolo claw and out the back plate. My daughter was sick this morning, so I had to stay home with her, which meant I had a lot of time to tinker. After burning through two batteries, I hacked up an old AC adapter (9 VDC, 210 mA) and soldered on a 9 V battery connector. I think I'll not be buying batteries for a bit... probably should have done that a lot sooner. My preamp entirely failed this morning and frustrated, I built another, a 1 stage inverting based on the LM741 (I have several to tinker with and I know... 741 is even a worse choice than the TL082), but it works. I built in variable gain (2X to 5X). I tried the new preamp with an amplified speaker set and it sounds fine. Then, I tried it with the LM386 amp circuit and I got really bad hum. This does not sound like squeal from being too close to a magnet. Distance does not seem to matter at all. This sounds like 60-cycle hum, but very pronounced. This happened before and this is why I first decided to move away from the LM386. I do not have easy access to the J201 JFETs and I have read here many times that the fetzer was never designed to be really good and clean. The other reason I do not like the fetzer ruby is too many pots! How is anyone supposed to figure out how to set the thing when there are three possible places to go up or down and the effects are mostly inaudible? Anyway, I did try the move to a .022 uF decoupling cap as you mentioned last week, but this did not work either. You meantioned that you weren't sure your circuit even had a decoupling cap in there. Does the 386 not need one? Wouldn't that mean you are putting gain on the AC plus a 4.5 VDC offset? I should mention I do get sustain with the LM386 circuit, but it is weak with my best attempts at adjusting the circuit and while I am patient, I am not that patient. So I got frustrated and went back to the TDA7267 amp. I get strong sustain on all six strings with the 2nd string ( being the strongest, but I have that same annoying hum as I did with the LM386! It is not as pronounced, but it is still unacceptable... sounds like noisy power, like if you have ever hooked up an amplifier in an automobile and heard the engine idle coming through when the music was quiet. I noticed the noise is exactly the same pitch as an open 2nd string B note. Coincidence? I should also mention the sustain is not on all frets, but rather in nodes, strong on some frets and inexistent on others, yeah strange!!! The sustain is for the most part harmonic in nature. Switching the intput leads gived me no sustain, but leaving them... an open low E goes into a killer harmonic bloom that sounds incredible with heavy distortion, then I only get sustain on certain frets moving up the neck, as if I am hitting certain nodes as I move along, that it likes. The same goes for all the other strings. I suspect another phase shift problem. I thought I had that kicked, but will have to look again on the scope tomorrow. Enough negativity though. Now that I have a taste of playing with it, I am hooked and won't give up until my Fender really sings. The blooms are really kind of magical-sounding and to feel the string vibrating or attempting to as you dampen them is also a very new, awesome sensation. This has to be the coolest specialized application of electromagnetics. Link to comment Share on other sites More sharing options...
psw Posted January 22, 2009 Author Report Share Posted January 22, 2009 Enough negativity though. Now that I have a taste of playing with it, I am hooked and won't give up until my Fender really sings. The blooms are really kind of magical-sounding and to feel the string vibrating or attempting to as you dampen them is also a very new, awesome sensation. This has to be the coolest specialized application of electromagnetics. Yay...some positive feedback! Seriously though, now you are getting a taste for it and this experience (that I first had a real taste of in page two with a single string driver) is what has really kept this thread going and people like myself stick at it for so long. This kind of comment really is why I stick around and so a big THANKS for that. As for the hum... possibly something in the circuits, definitely think about getting back to batteries, yes it will kind of chew through batteries, especially a higher powered amp...remote power is a decent idea but be careful, you are connecting the ground directly to the strings and the amp through the common ground. Obviously you will get more power and possibly headroom but noise and circuit instability can result. Any powersupply used needs to be incredibly well regulated and remember that you can get false results with powersupplies in that while the voltage may be unregulated it could be drawing any amount of current. Also, wasn't clear that you were taking it from after the controls (a little lazy there)...take a line directly from the bridge pickup and do disconnect the middle pickup completely...ok for preliminary testing, but you are beyond that and hopes that it will work when everyone has failed will not be enough. Have a look at the kind of things I and others have done with dual coil drivers to control EMI in particular my mid-driver experiments on my strat. Even though you are not getting squeal through the bridge pickup, magnetic coupling can be putting driver noise into the ground and out the jack. The controls also add a fir bit of noise also...this kind of thing is part of the challenge of installation. Speaking of which...while people should definitely test the device by holding it above the strings away from all pickups as you have done...installing the driver down in the guitar under the strings usually helps as long as things are disconnected. Also, be aware that EMI can run through the metal strings to be picked up by the bridge pickup causing effects like fizz and noise. Resist the temptation to add as much power as you can to solve these problems...in fact the best and most practical effects are with the minimum amount of power to produce the effect...it is possible with an efficient driver and non oscillating circuit to get good clean sustain with relatively low power drain...but it is a balancing act...so keep at it. Disconnect all but the essentials, remove earthing problems like powersupplies and start working backwards to identify the problem/s Anyway...CONGRATULATIONS...it is a kind of magical thing. If you have kids around show them, one of my happiest memories was to show my earliest success with a tiny 10mm one string driver held next to a string...I had to show someone so I got my daughter who was fascinated...in fact so fascinated at 7 or 8 years old that I caught her more than once sneaking in to try it without asking...hehhee pete Link to comment Share on other sites More sharing options...
mrjstudios Posted January 22, 2009 Report Share Posted January 22, 2009 I tried the new preamp with an amplified speaker set and it sounds fine. Then, I tried it with the LM386 amp circuit and I got really bad hum. This does not sound like squeal from being too close to a magnet. Distance does not seem to matter at all. This sounds like 60-cycle hum, but very pronounced. This happened before and this is why I first decided to move away from the LM386. I do not have easy access to the J201 JFETs and I have read here many times that the fetzer was never designed to be really good and clean. The other reason I do not like the fetzer ruby is too many pots! How is anyone supposed to figure out how to set the thing when there are three possible places to go up or down and the effects are mostly inaudible? I have also had this noise problem with my sustainer circuits. Do you only get it when you turn the thing up to a certain point? Mine always would start in buzzing rather quickly, and as you went up in power, the buzz frequency would change a bit and sort of 'sweep' across a range of notes, and then settle on 1 nasty hum, regardless of adding any more power. I would describe the final hum as sounding like a 60 cycle hum, or the car engine/amp analogy. It IS NOT the 386 itself, since I have had plenty of perfectly working 386 circuits... but, it seems to be a recurring problem at least with F/R based circuits. I actually spent a lot of time recently on my previous 2 circuit attempts (I should add, these circuits were NOT the new schematics I have posted -- they were differently and less modded F/R's) trying to rid them of this buzz... hmmm... some troubleshooting: Keep in mind my test guitar has only a bridge humbucker, and a single 500K volume control, so I doubt this buzz is caused by other pickups or guitar switching/electronics. (Note: As Pete and others have discovered and have said numerous times, other pickups in your guitar can and will cause problems if not dealt with correctly... but in this case, I am ignoring that set of problems for troubleshooting purposes, since I have eliminated them from my setup.) The buzz I experienced was totally uneffected by outside forces such as EM radiation, computers, tvs, lights, etc. No matter where the guitar was, it buzzed the same. So if it is a grounding/power supply issue with the F/R type circuit, it must be internal with the interfaced guitar and sustainer circuits, and not an external shielding issue. The buzz like I had, and you seemed to describe, is definitely NOT a result of driver/pickup feedback and interference. That is more of a squeel and is effected by driver position, etc -- this buzz is not (trust me, I tried moving it all over the place...) Soo.... that kinda leaves 2 things. Slightly bad driver (and I say slightly bad because even a driver that internally vibrates and has flaws CAN work to an extent, although never well), bad circuit. The circuit could be anything from design, to bad layout arrangement, to bad solder joints, etc. Maybe check where your input voltage is running carefully... good luck man! Link to comment Share on other sites More sharing options...
psw Posted January 22, 2009 Author Report Share Posted January 22, 2009 I am not sure what the problems are with this noise...leads should be short, especially driver leads and kept away from signal wires and pickups (consider the driver leads to be an extention of the driver coil itself) and be aware that shielding as we normally think of it in guitars...RFI suppression through copper and the like...will do nothing against EMI and may even cause troubles if eddy currents are formed through the magnetic frequency stuff. But mostly such things are hear as the mysterious "fizz" distortion, not this kind of noise. You can get noise through the controls and the tone cap if taking the signal after it...so that's not the best idea. It sounds like something to do with the circuit...i was not aware of problems in that regard with the F/R thing and have no personal experience with that particular circuit, obviously some have been able to do this project without this problem. Is the sustain "clean" (as in no fizz or distortion effect when on)...there should be no change to the oputput and the tone of the guitar when the circuit is in use or installed ideally. With the mods I use on the LM386 (taken from the data sheet mainly) i have had very little internal oscillation problems at high gains. It may be something to do with the driver, but it seems odd. Is moving the driver away from the pickups, right up the neck clear the problem? Generally a poorly made or potted driver will be less efficient and cause just low performance, generally in the higher strings...however...if there is any internal vibration (sometimes you can feel the windings vibrate when touching the thing) this can cause it's own signal to be created and get into the ground (which of course is shared by the circuit and the guitar as well as one end of the driver coil and the power supply or battery) and produce noise. Welcome to the world of installation problems. A lot of these things are less explored as many people have used guitars with only a single bridge pickup that only requires the device to be turned on...all of my guitars have been multipickup guitars though. Anyway...having had a taste, I am sure you now have the motivation to fix the problems and even go further from there. Once you have a successful installation it is not hard to install a new driver or circuit idea as things are essentially modular...but it does help to have something running to compare and make improvements to. One of the things that knocked the wind out of my sails with commercializing the ultra thin driver thing and my present circuit is these very problems that are quite frustrating and will need to be addressed on a case by case basis...until people can consistently get these things going well, I am kind of loathe to open a huge can of worms. But stick with it and report any finding about the problems and the fixes as this will help again...and again congratulations... pete Link to comment Share on other sites More sharing options...
Hank McSpank Posted January 22, 2009 Report Share Posted January 22, 2009 (edited) the NE5532N is an op amp, not a poweramp, it is unlikely to put out the kind of power or handle the impedance typical of driver applications... Yes I know...but remember, I'm going to try a string driver that has a higher impedance (the aim being lower power per string) & this particular chip can drive low loads (unusual for an opamp), eg... http://www.elecfree.com/electronic/portabl...fier-by-ne5532/ In that circuit it provides 50mW RMS @9V into 32 Ohm (with very low THD), which doesn't sound like a lot, but if I can get a really focused string driver it may work ....if not, perhaps crank the VCC up (it goes as high as 22V) to suck more power out of it. Ultimately, if I have no success, I'll get 30p's worth of fun out of it by leaving it upturned on my wife's favourite seat ;-) Like I say, I reckon for a hex pickup to work, each individual driver (& circuit) will likely need to be per string 'customised' & should be driven with the least power that I can get away with! Edited January 22, 2009 by Hank McSpank Link to comment Share on other sites More sharing options...
psw Posted January 22, 2009 Author Report Share Posted January 22, 2009 Well...i think you may be over estimating what can be done with how little power...but working with the least amount of power necessary is always a good approach...obviously less power out would equate to less EMI and more practical battery consumption. I wouldn't be too hopeful with this kind of circuit however...there are a lot of assumptions based on a little bit of naivety still I think. Instead of 8 ohm coils, you are now looking at even more turn coils, obviously with thinner wire to get that small and a completely different geometry (depth relative to width and length). Besides the power problems with the circuit scheme...the driver/s are the crucial part of this project...the circuit is only a means to provide the signal with sufficient current. So, your design needs to be able to cope with a whole range of electromagnetic affects and you will need to get a grasp on some of this esoterica to know what is going on...after all, if it doesn't work, you are likely to get a scream at best, nothing is more likely...so how will you know how to progress (personally I'd be aiming for the appropriate effect and then scaling back the power and driver size to acertain what's working and what isn't). Some of the effects you need to consider is the resonance and lag within the coil. It has generally been assumed that in the "thin driver" theory, I have hit upon a unique coil design that operates largely in the resistance area (not altering that much with frequency and alleviating much of the phase effects) and does not generate that much "spring" in the coil. By this I mean...speed. Consider the coil and the core as a magnet that changes polarity (this is a simplified analogy)...pretend it is no particular polarity for now, applying current to the coil will create a magnetic field depending on the direction of flow in the coil...so apply a DC current and you get say north polarity. Now, cut the power...what happens. Well, the core may well retain some of this polarity like a nail becomes a temporary magnet for a while...similar things happen within the coil. The electrons are going one way and there is some momentum. Ok, now apply a DC current in the reverse direction...what happens. The core will be magnetized south...but to do this, it will need to overcome the cores new north polarity as it has become a temporary magnet, and it will have to work against the current flow of the previous current. Of course, simply switching flow like this is not really a problem and the coil being momentarily off helps relax it and the core...however. In this project we are switching thousands of times a second much of the time...the faster it switches, the more difficult it is going to find it and so it will struggle more and more to stay true to the signal feeding it. Anyway...for a short little visualization at 7am in the morning...this might help readers get a little bit of a grasp of the kind of considerations required for driver design. My "belief" with the thin driver design is that this geometry puts as much of the coil as close to the string as possible, the limited profile reduces the EMI spread in harmful ways (remember you really do what the EMF directed towards the string as much as possible) and maximizes the number of overlapping turns while minimizing the internal core...all this allowing it to work more consistently at enough speed and power in the ranges required to do this job. There are side benefits in that this coil is compact and allows things like the pickup driver of the compact driver as used on the tele. Last year I was working a little on taking these principles further with some success but straying from the DIY thing as the coils are difficult to make. That is not to say other ways wont work...in fact my hex drivers were as small or smaller. Obviously things need to get very tight as the amount of space is reduced. You need to get tricky with the magnetic fields and exploring the free FEMM program will give you some clues perhaps as to the interaction between nearby magnets and coil effects. The "thin driver theory" came directly from my work with miniturizing hex drivers. After too long, I realized a lot of my success with these things (very hard won mind you) was actually because I had been making them smaller and thinner (the idea we were working on was a surface mounted driver...again the tele driver is a partial realization of this concept). To answer a challenge that in a year of work I had not achieved positive result or that the whole thing was a fake...i got a little angry. I was sure that I could do a simple one pretty easily, but I was trying to work towards something "greater". I took the exact same circuit I was using for the hex things at the time and made a few compact coils and within a week this design idea was up and running. The success and potential of this simple solution is what finally swayed me away and to reconsider the supposed merits of the Hex idea. anyway...way to early for such long posts I guess... pete Link to comment Share on other sites More sharing options...
Donovan Posted January 23, 2009 Report Share Posted January 23, 2009 I tried the new preamp with an amplified speaker set and it sounds fine. Then, I tried it with the LM386 amp circuit and I got really bad hum. This does not sound like squeal from being too close to a magnet. Distance does not seem to matter at all. This sounds like 60-cycle hum, but very pronounced. This happened before and this is why I first decided to move away from the LM386. I do not have easy access to the J201 JFETs and I have read here many times that the fetzer was never designed to be really good and clean. The other reason I do not like the fetzer ruby is too many pots! How is anyone supposed to figure out how to set the thing when there are three possible places to go up or down and the effects are mostly inaudible? I have also had this noise problem with my sustainer circuits. Do you only get it when you turn the thing up to a certain point? Mine always would start in buzzing rather quickly, and as you went up in power, the buzz frequency would change a bit and sort of 'sweep' across a range of notes, and then settle on 1 nasty hum, regardless of adding any more power. I would describe the final hum as sounding like a 60 cycle hum, or the car engine/amp analogy. It IS NOT the 386 itself, since I have had plenty of perfectly working 386 circuits... but, it seems to be a recurring problem at least with F/R based circuits. I actually spent a lot of time recently on my previous 2 circuit attempts (I should add, these circuits were NOT the new schematics I have posted -- they were differently and less modded F/R's) trying to rid them of this buzz... hmmm... some troubleshooting: Keep in mind my test guitar has only a bridge humbucker, and a single 500K volume control, so I doubt this buzz is caused by other pickups or guitar switching/electronics. (Note: As Pete and others have discovered and have said numerous times, other pickups in your guitar can and will cause problems if not dealt with correctly... but in this case, I am ignoring that set of problems for troubleshooting purposes, since I have eliminated them from my setup.) The buzz I experienced was totally uneffected by outside forces such as EM radiation, computers, tvs, lights, etc. No matter where the guitar was, it buzzed the same. So if it is a grounding/power supply issue with the F/R type circuit, it must be internal with the interfaced guitar and sustainer circuits, and not an external shielding issue. The buzz like I had, and you seemed to describe, is definitely NOT a result of driver/pickup feedback and interference. That is more of a squeel and is effected by driver position, etc -- this buzz is not (trust me, I tried moving it all over the place...) Soo.... that kinda leaves 2 things. Slightly bad driver (and I say slightly bad because even a driver that internally vibrates and has flaws CAN work to an extent, although never well), bad circuit. The circuit could be anything from design, to bad layout arrangement, to bad solder joints, etc. Maybe check where your input voltage is running carefully... good luck man! Yes, I only get it when I turn it up to a certain point and it seems what you have described is identical to what I have experienced. I did some reading today suggesting that there is more to choosing a decoupling capacitor than just its value and that sometimes you might introduce more problems if the cap is not carefullt chosen. I am wondering if this might be the case. I am going to play around some more this weekend, but I am moving to breadboard as I am tired of trying to troubleshoot densely populated perfboards. I don't think it is my driver construction unless it is something specific about that dimensions causing some internal or intermingling oscillation? The dimensions are spot on what Pete has specified, the resistance is good (7.9 ohms) and the thing is quite solid as I potted with urethane varnish while winding and then vacuum potted it to degas under 32 inches of HG. I have pushed the magnets into the bobbin, making their ends level with the top of the bobbin surface. Should they be lower? Link to comment Share on other sites More sharing options...
psw Posted January 23, 2009 Author Report Share Posted January 23, 2009 No...i think the driver sounds great...obviously it can work. How have you got it wired at the moment though...taking the signal directly from the bridge pickup before the controls should help a fair bit...you can run a temporary wire under the scratchplate so you can continue to work on circuit things. Also...make sure the driver is close to the strings and the bridge pickup as well...this tends to help with any EMI problems and adjust from there. Definitely disconnect both the hot an ground wires of the middle pickup and see if that works...much as you may wish to be able to use the sustainer with the middle pickup this basic design has proved time and again not to be able to do that. Much work went into a mid driver for a strat, but unfortuantely with little success. Last year I was working on a tele version that I hoped to surface mount between the two pickups and not only make use of either pickup but significantly ease the installation process by avoiding switching (my real motivation)...however, alas even with an innovative dual bilateral coil with internal magnets...it was not to be. I can only assume that my other mid-driver experiments and people like curtis' have also failed to work adequately. SO much work yet to be done...for myself I am semi retired on the sustainer thing for a bit I'm afraid...at least with more adventurous R&D, but I'm more than keen to see this work continue...keep up the good work and perseverance... pete Link to comment Share on other sites More sharing options...
mrjstudios Posted January 23, 2009 Report Share Posted January 23, 2009 Yes, I only get it when I turn it up to a certain point and it seems what you have described is identical to what I have experienced. I did some reading today suggesting that there is more to choosing a decoupling capacitor than just its value and that sometimes you might introduce more problems if the cap is not carefullt chosen. I am wondering if this might be the case. I am going to play around some more this weekend, but I am moving to breadboard as I am tired of trying to troubleshoot densely populated perfboards. I don't think it is my driver construction unless it is something specific about that dimensions causing some internal or intermingling oscillation? The dimensions are spot on what Pete has specified, the resistance is good (7.9 ohms) and the thing is quite solid as I potted with urethane varnish while winding and then vacuum potted it to degas under 32 inches of HG. I have pushed the magnets into the bobbin, making their ends level with the top of the bobbin surface. Should they be lower? Which capacitor are you refering to? Is it in the part of the circuit that is like the one 1 posted, or is it in your new preamp? I've just gotten the rest of the parts today that I need to build a from-scratch version of my circuit layout (found a few pages back). I know the older F/R-like layout works, but there are things I don't like about it so I'll compare the two, and see if my new layout fixes the problems. I'm also re-wiring the guitar again from the ground up, so hopefully this latest attempt will produce a (consistently) working sustainer. If it does, I'll definitely post some demo sound clips and videos too. I'm going to work on the new unit over the weekend, so we'll see how far I get... Link to comment Share on other sites More sharing options...
Donovan Posted January 24, 2009 Report Share Posted January 24, 2009 (edited) Yes, I only get it when I turn it up to a certain point and it seems what you have described is identical to what I have experienced. I did some reading today suggesting that there is more to choosing a decoupling capacitor than just its value and that sometimes you might introduce more problems if the cap is not carefullt chosen. I am wondering if this might be the case. I am going to play around some more this weekend, but I am moving to breadboard as I am tired of trying to troubleshoot densely populated perfboards. I don't think it is my driver construction unless it is something specific about that dimensions causing some internal or intermingling oscillation? The dimensions are spot on what Pete has specified, the resistance is good (7.9 ohms) and the thing is quite solid as I potted with urethane varnish while winding and then vacuum potted it to degas under 32 inches of HG. I have pushed the magnets into the bobbin, making their ends level with the top of the bobbin surface. Should they be lower? Which capacitor are you refering to? Is it in the part of the circuit that is like the one 1 posted, or is it in your new preamp? I've just gotten the rest of the parts today that I need to build a from-scratch version of my circuit layout (found a few pages back). I know the older F/R-like layout works, but there are things I don't like about it so I'll compare the two, and see if my new layout fixes the problems. I'm also re-wiring the guitar again from the ground up, so hopefully this latest attempt will produce a (consistently) working sustainer. If it does, I'll definitely post some demo sound clips and videos too. I'm going to work on the new unit over the weekend, so we'll see how far I get... Hi MRJ. Good luck with your rewire. Can't wait to hear your sound clips. I am referring to your C2, supply decoupling, bridging Vs and Gnd. From what I have read, that should be placed as close to the IC body as possible as you can pick up noise anywhere in between the cap and the IC and that will help to smooth it out. I experimented with my op amp preamp tonight and found that noise decreases as I raise the value of this cap, but the biggest one I had was 470 uF. A 1000 uF might even be better. One effect of a larger value is when you kill the circuit, it runs for a few extra seconds as the cap discharges. I got my preamp working a lot better tonight. Pete, you are absolutely right about using an AC adapter for testing. It is 100 X noisier than a battery. The one I have is a floating ground. Perhaps one with an earth ground would work. When my band plays, we always use a power conditioner, so I will be curious to see its effects as well. Some interesting effects during testing with a battery... touching nothing but the battery case during play through a speaker increases volume of signal and noise (or gain, not sure), touching nothing but electrolytic capacitor body tops during play quiets noise. These circuits themselves are very prone to picking up noise. One fequency I am picking up is exactly the same frequency as an open B string! Strange. I also found my C7 was an error on my part. I removed it and flipped a couple connections and now 1 less component. Now, it takes the 4.5 VDC and AC swing, compares it to 4.5 straight volts, and amplifies the difference (the AC swing). This is more efficient, BUT, I am beginning to think with these op amps it would be alot better to use 1% tolerance resistors on my voltage dividers (R1 & R2, R7 & R8), as mismatches will lead to amplification of the DC (junk). I also confirmed tonight that the TDA7267 will not accept a volume control pot at all. It must have a capacitor as the last component before the input. I have no idea how it "knows" this. I am going to order some of Strib's IC's (TBA820M) as I think this is a better choice and Strib's sustain sounded nice, even using the antiquated LM741. I am getting nice harmonic sustain, but still no fundamental mode. More testing on the scope is necessary to confirm what I am 99% sure is a phase issue. Next, I am going to create a bandpass filter with a band of 80Hz to 8kHz as this seems to be about the guitar's range and see how this helps my noise issues as I find it more important than missing the fundamental mode. One thing I have not seen discussed is the fact that once harmonics bloom, the pickup is then sending this harmonic signal to the circuit, then with circuit amplifying the harmonic, not the fundamental, the driver must be pushing that same harmonic. I wonder what the effect will be if my filter cuts out the higher harmonic frequenices. In other words, if I cut any frequency above a normally fretted 24th fret on high E, any harmonic above that frequency will be ignored, not amplified. I am speculating that assuming there were no phase issues, it might cause an oscillation between fundamental and harmonic, or keep the note just on the edge of becoming a harmonic. What do you guys think? I do want to get that working, but to be honest, I am in this for the harmonic mode. I can't wait to play Santo and Johnny's "Sleepwalk" live with that! It is going to be so sweet. I also think my driver may be trying to rattle wires inside my guitar! ...or, my driver is slightly microphonic. I can hear a very slight, very high frequency tone emanating from somewhere beneath the pickguard area, but can not confirm the exact source. I also suspect it may be my bridge pickup, Duncan JB full-size. I may rewind it (driver) yet again and try a different potting material. Who knows, Pete, I may even try PVA, but that would be conforming to confirmed methods and we know we can't have that! For anyone interested, here is an awesome link on op amp basics... the whole site in general is an indispensable resource for anyone as new to all this as I am... ALL ABOUT OP AMPS The end of the article makes some recommendations on op amp sourcing by application. There are even op amps that can put out 100's of mA. That might be nice to cut this circuit down to 1 IC. There goes half the components and probably the phase shifts with them! I found some others too that are very fast and clean according to datasheet, much better than TL082 or even 072. Check out OP275. Very low noise, kick-arse slew rate of 22 V/uS which can keep up with changes 44 X the speed of the LM741 and 26 X the speed of the TL082. I think once noise is sorted, this is going to be a better preamp than the fetzer valve. Op amps seem much easier to set gain. You can do it with resistor and pot choices instead of having to bias anything so tediously as the JFET. I think you guys are going for no gain on the JFET, correct? To do this with the opamp, you just leave out the resistors and pot on the negative feedback loop, easy! That is one reason I am staying away from the JFETs. And that reminds me, maybe I need to try no gain. I have been putting in minimums of 2 X. Edited January 24, 2009 by Donovan Link to comment Share on other sites More sharing options...
psw Posted January 24, 2009 Author Report Share Posted January 24, 2009 It's nice to see you all going through the motions...in the end I settled for simpler, lower gains, more control and available parts. I then took what I could and shrank the thing down as small as I could. Any caps in the circuit will be causing delays and thus phase issues I fear...much as we'd all like to innovate...there is a lot to be said for the LM386...and even though i always liked the idea of opamps (mainly because they offered a platform for further development of things like AGC or filter controls) they are not necessary...remember, the main if only reason for the 'preamp' stage at all is to prevent loading. Also be aware, where ever you have caps you have power storage that will be released as soon as it is turned off...that and the coil backlash phenomenon could cause havoc for silent swithing, especially switching off of the device...remember most of these caps connect to ground which will remain connected to the guitar's ground to which it will all drain and exit via the amp as some kind of "pop" I suspect regardless of "anti-pop" circuitry. Altogether, interesting stuff...but perhaps aiming too high in the power stakes. The driver does sound like it is vibrating, confirming my reservations about potting in this manner...if it is vibrating or making a sound, there must still be some vibration in there I suspect. Most of these kinds of conventional potting does not fill all the voids with this relatively thick wire and tends to shrink on drying leaving lots of gaps between the rounds...if you can picture what is going on in there. The PVA while a little soft, is safe, easy to clean up and tends to adequately fill all the gaps enough, or damp any vibration without going brittle. Contrary to the impression some people seem to get...the design, technique and materials have been very carefully chosen and tested against alternatives...it is not the only way...but it is the safest, cheapest, and most reliable method for DIY. Epoxy coils can be great but take considerable effort and special epoxies...don't even think of using the hardware crap and especially 5 minute stuff...I spent over $100 finding a suitable epoxy to build the ultra-thin designs before I even knew if such a design would work! Such is the price of innovation, but the cost is high if you keep pushing things. Very soon you can have spent as much as a very good commercial system if you are not careful! pete meanwhile...i spent $1,100 on the car this week and today I blew a tyre, so it is likely to have to get new tyres all round the way things are...maybe this is telling me to pull my finger out and build up these circuits I have been promising...if only i can work out the ebay/paypal selling side of things too...so much to learn! Link to comment Share on other sites More sharing options...
Hank McSpank Posted January 24, 2009 Report Share Posted January 24, 2009 (edited) I am getting nice harmonic sustain, but still no fundamental mode. More testing on the scope is necessary to confirm what I am 99% sure is a phase issue. Next, I am going to create a bandpass filter with a band of 80Hz to 8kHz as this seems to be about the guitar's range and see how this helps my noise issues as I find it more important than missing the fundamental mode. For fundamental frequencies, I reckon this is the band of frequencies (for a 24 fret neck)... String 6 E = 83Hz open string thru 332hz (highest fret) - however to allow for alternate tunings, say 70Hz thru 400hz String 5 A = 110Hz open string thru 440hz (highest fret) - however to allow for alternate tunings, say 85Hz thru 500hz String 4 D = 146.8Hz open string thru 552Hz (highest fret) - however to allow for alternate tunings, say 110Hz thru 600hz String 3 G = 196.0Hz open string thru 784Hz (highest fret) - however to allow for alternate tunings, say 150Hz thru 820hz String 2 B = 246.9 Hz open string thru 987.6Hz (highest fret) - however to allow for alternate tunings, say 210Hz thru 1050hz String 1 E = 329.6Hz open string thru 1,318Hz (highest fret) - - however to allow for alternate tunings, say 290Hz thru 1480hz but for a sustainer, you'd obviously want the octave harmonic, so when factoring for filters, you'd need to double those figures above. Edited January 24, 2009 by Hank McSpank Link to comment Share on other sites More sharing options...
mrjstudios Posted January 24, 2009 Report Share Posted January 24, 2009 I am referring to your C2, supply decoupling, bridging Vs and Gnd. From what I have read, that should be placed as close to the IC body as possible as you can pick up noise anywhere in between the cap and the IC and that will help to smooth it out. I experimented with my op amp preamp tonight and found that noise decreases as I raise the value of this cap, but the biggest one I had was 470 uF. A 1000 uF might even be better. One effect of a larger value is when you kill the circuit, it runs for a few extra seconds as the cap discharges. If you look at the 2nd drawing I posted, I moved C2 (and I think it is called C5 in the second one) right next to the IC chip. Like I said before, there were things about the original F/R layout I didn't like.... The from scratch circuit I am working on will be the 2nd (new version) drawing that I posted. Link to comment Share on other sites More sharing options...
Donovan Posted January 25, 2009 Report Share Posted January 25, 2009 I am getting nice harmonic sustain, but still no fundamental mode. More testing on the scope is necessary to confirm what I am 99% sure is a phase issue. Next, I am going to create a bandpass filter with a band of 80Hz to 8kHz as this seems to be about the guitar's range and see how this helps my noise issues as I find it more important than missing the fundamental mode. For fundamental frequencies, I reckon this is the band of frequencies (for a 24 fret neck)... String 6 E = 83Hz open string thru 332hz (highest fret) - however to allow for alternate tunings, say 70Hz thru 400hz String 5 A = 110Hz open string thru 440hz (highest fret) - however to allow for alternate tunings, say 85Hz thru 500hz String 4 D = 146.8Hz open string thru 552Hz (highest fret) - however to allow for alternate tunings, say 110Hz thru 600hz String 3 G = 196.0Hz open string thru 784Hz (highest fret) - however to allow for alternate tunings, say 150Hz thru 820hz String 2 B = 246.9 Hz open string thru 987.6Hz (highest fret) - however to allow for alternate tunings, say 210Hz thru 1050hz String 1 E = 329.6Hz open string thru 1,318Hz (highest fret) - - however to allow for alternate tunings, say 290Hz thru 1480hz but for a sustainer, you'd obviously want the octave harmonic, so when factoring for filters, you'd need to double those figures above. Yes, thank you for the correction! I don't have the foggiest how I ended up with the 8kHz! I am designing an opamp bandpass filter today for the range of 70-2960... will follow with preliminary schematic. Link to comment Share on other sites More sharing options...
Donovan Posted January 25, 2009 Report Share Posted January 25, 2009 I am referring to your C2, supply decoupling, bridging Vs and Gnd. From what I have read, that should be placed as close to the IC body as possible as you can pick up noise anywhere in between the cap and the IC and that will help to smooth it out. I experimented with my op amp preamp tonight and found that noise decreases as I raise the value of this cap, but the biggest one I had was 470 uF. A 1000 uF might even be better. One effect of a larger value is when you kill the circuit, it runs for a few extra seconds as the cap discharges. If you look at the 2nd drawing I posted, I moved C2 (and I think it is called C5 in the second one) right next to the IC chip. Like I said before, there were things about the original F/R layout I didn't like.... The from scratch circuit I am working on will be the 2nd (new version) drawing that I posted. Yes, that ought to keep any noise picked up in between to a minimum. Link to comment Share on other sites More sharing options...
Donovan Posted January 25, 2009 Report Share Posted January 25, 2009 Would anyone care to comment on the point I raised previously? One thing I have not seen discussed is the fact that once harmonics bloom, the pickup is then sending this harmonic signal to the circuit, then with circuit amplifying the harmonic, not the fundamental, the driver must be pushing that same harmonic. I wonder what the effect will be if my filter cuts out the higher harmonic frequenices. In other words, if I cut any frequency above a normally fretted 24th fret on high E, any harmonic above that frequency will be ignored, not amplified. I am speculating that assuming there were no phase issues, it might cause an oscillation between fundamental and harmonic, or keep the note just on the edge of becoming a harmonic. What do you guys think? Link to comment Share on other sites More sharing options...
psw Posted January 25, 2009 Author Report Share Posted January 25, 2009 I just woke up...kind of...got to go back to bed in a bit... however... The harmonic mode works like this. The driver when "reversed' (this can be done by physically flipping the magnet over or reversing the phase of the driver or signal leads)..in other words reversing the phase...which one might suspect an anti-sustainer (and in some rare instances you can kind of see hear this effect which is similar to the moog damping thing on some guitars). What happens in practice is that the fundamental is suppressed but the harmonics which have a different set of nodes along the string will be driven. Exactly like the light touch at the 12th fret suppressing the main fundamental string vibration to reveal the harmonic within it. IN the case of a fixed driver with string length shortened by fretting, the type of harmonic could be a different harmonic of course than the octave. Another factor in this is the position of the bridge pickup along the string and the harmonic content of the signal going into the circuit. The reality is that the working of the sustainer is fairly organic...unlike a signal processor like a chorus that will put a wobble on anything, or a sampling effect that will hold a note by sample and hold means regardless of the string still vibrating...this is actually affecting the way the physical string vibrates. As a result there are physical limits... SO...yes there is that idea that once the string is playing a harmonic, it is now reading the strings vibration as that note (perhaps twice the speed or typically far more) and then sending the signal back through the driver in reverse to which you might expect that it will seek to drive yet a higher harmonic. IN fact this is true, so...there is an affect I can get where if you switch to harmonic, and then back to fundamental you may be able to get an even higher harmonic out if it from the transition as the driver is again reversed (not the most predictable of effects, but possible). Generally though, it seems to vibrate quite happily at a harmonic and stay there. Another technique btw is the reverse harmonic...if you play a harmonic in fundamental mode...sometimes it will stay, but usually it will bloom in reverse....going from the harmonic back to the fundamental. "Bloom" can be very attractive and why I used that 100uF output cap as a decent compromise giving bloom on the lower strings even in fundamental mode. However, you can get similar harmonic affects by driving the string harder (however this is limited by the EMI affects)... There is also the bias of the amps drive than that makes a difference...so harmonic effects can be created by having the amp more treble biased (as with the low value output cap above)...so a band pass filter could also produce some interesting "mix" results, altering the "bloom" effect without reversing the driver. These things have been discussed a bit...I think col's circuit played with it a bit and he certainly put a bit of thought into this aspect as I recall...a bit of searching required for you I fear! ... As for filtering...filtering out frequencies above the hearing range is always a good idea and lower as well...how far I am not sure! I must have missed the frequencies for each string thing...i think we may have discussed this kind of thing...listings like this and the string tensions and other factors that might be relevant are given over at DGB studios as I recall. Beware making things too complicated and theoretical at first...there is a lot that is 'unknown' and unexpected with this project...again, it is not like a signal processor. For instance, the driver/s itself are big unpredictable filters (just like different pickups have their own sound) for one. This means that although you could design a circuit as neutral or optimum as you like...once you hook up a driver to it, the true phase differences could make a complete mockery of all your plans...and the frustrating thing is that you may never know. Adjustability is possibly the key...the location of the driver and the sounce pickups being fixed also plays a role...there are so many variables and unpredictables...so as you fret the notes and the string shortens, all kinds of ratios of vibration modes are altered, yet the ratios of the pickup and driver remain constant! Anyway...rambling a little...but the nature of the "thin coil theory" is that this unique driver design appears to work in a reasonably fast and consistent manner for the kind of application and frequencies at work on a guitar...varying from this design may result in other measures being taken to compensate...the commercial systems being a case in point with quite elaborate frequency dependent phase compensation circuitry required. As I don't have the skills and practical knowledge to design such things (and it would only serve to redesign what already is) I was encouraged from an early stage here by LK to look at the driver design to address the problems with basic amplification circuits...things like the "thin coil" were the results of this pursuit. If you can't find another way to design a driver to produce such affects, you may well need to approach the problems with fancy compensation strategies I fear...certainly that appears to have been my experience. anyway...much longer than I expected as usual...not sure if that is any help at all, confusing, frustrating...or serving only to make a long thread even longer... carry on... pete Link to comment Share on other sites More sharing options...
col Posted January 26, 2009 Report Share Posted January 26, 2009 Would anyone care to comment on the point I raised previously? One thing I have not seen discussed is the fact that once harmonics bloom, the pickup is then sending this harmonic signal to the circuit, then with circuit amplifying the harmonic, not the fundamental, the driver must be pushing that same harmonic. I wonder what the effect will be if my filter cuts out the higher harmonic frequencies. In other words, if I cut any frequency above a normally fretted 24th fret on high E, any harmonic above that frequency will be ignored, not amplified. I am speculating that assuming there were no phase issues, it might cause an oscillation between fundamental and harmonic, or keep the note just on the edge of becoming a harmonic. What do you guys think? Long time no post from me - got no time to make much impact these days, so I just lurk occasionally. My best guess as to what makes the bloom work is as follows: simple reversal of signal by flipping the magnet or swapping the wires does - as Pete suggests - cancel the fundamental frequency leaving the harmonic... the question is, why isn't that harmonic then canceled followed by the next and then the next, quickly taking the whole thing out of the frequency range of the circuit ? Simple answer is: As the frequency rises, the phase response of the system (pickup, circuit, driver and physical gap between pickup and driver) changes. At some point, as the harmonic rises, there is a sweet spot where the 180º shift of the 'harmonic mode' is offset enough by the phase shift of the system that the sound is boosted instead of canceled. Where this sweet spot happens will depend on the circuit used, the inductance of the driver and the pickup used, this is why some folks can get a sweet bloom easily, others get little or none, and yet others can't get anything but crazy harmonics! There are two ways to control this: #1 build many many circuits and drivers and try combinations until you get something like the result you are after. #2 build a few and use theory and measurements to calculate the best settings before building your 'final' (lol) system. I guess this effect is one of the reasons why commercial units use 'phase cancellation' circuitry. It allows them to increase the sweet spot so that there is a more even and predictable response over the whole range of the guitar, and so that their systems will work well with a broader range of instruments. ---------------------------------------------------- A 180º toggle of phase is not the only way to create a harmonic mode, I have had success using standard high pass filters and also using all pass filters. The best results I have had aside from the 180º phase flip have been from the all-pass filters. This approach gives you much more scope for fine tuning the response to fit with the rest of the system. For example, you can set it up so that the lower notes stay fundamental while the higher ones give a nice harmonic bloom. If you are going to use a 180º phase flip, I recommend that you use an op-amp buffer that can flip the phase rather than using a switch that toggles the driver connections. The physical switch approach will leave you with more noise and 'grunge' on one of your modes. (can't remember why off hand, its a long time ago, but there is a real reason why this is the case. This is one of the revisions of my old circuit - I'm sure there are lots of problems with it, but you can see how its possible to get a loit of mileage out of a single op-amp. Look at the third op-amp from the left (the left most two are power supply and input buffer/amp) that third one with all the switching before it provides all the mode switching: normal, 180º, high-pass and all-pass. All from one op-amp and a 4-way rotary switch. You probably cannot just drop it into any old circuit because of impedance issues, but it is possible to get this sort of thing happening. anyhow, gotta run cheers Col Link to comment Share on other sites More sharing options...
psw Posted January 26, 2009 Author Report Share Posted January 26, 2009 Good to hear from you again col...and to have the post brought forward for the newer experimenters in sustainerdom...plus a long post that rivals mine without the rambling A lot of what is being talked about and brain crunched is of course the same kind of things we were doing back then and it is probably worth digging through the thread to find the eras where such things were discussed and much work done...so in this case, look for where col and curtisA were fairly active perhaps. Another important part of this is the source signal...much of this is overlooked but also suffers from phase differences and filter like effects...a telecaster pickup poses some unusual harmonic effects sometimes compared to a very midrangy HB for instance. I am not surprised that some or all of fernandes kits also come with their own HB bridge pickup as well as neck driver...hmmm. Part of the point being is that pickups, using similar technologies, suffer similarly from phase type effects...many of which may not be apparent till you try and regenerate this signal back through a driver and back onto the physical vibration of the strings. Another aspect is of course that the signal pickup and driver location are at different points along the string...causing differences again. My 'argument' in the early stages is that people should try and crawl before they walk...there are so many aspects of this simple concept but difficult execution project to explore...there are so many things that are hard to appreciate till you have achieved some basic success (plus the bonus of the high you get by any kind of success in this...as donovan expressed recently and seems to be a universal effect) before you try and stand up and walk, or try and build the farrari of sustainers. Also, much of these unique ideas are likely only suitable for the particular guitar it is aimed for, particularly with hex type systems. ... Anyway...feeling fuzzy in the head this morning...saw Jeff Beck Last night...great show...makes one wonder why anyone would need a sustainer at all...hehehe. I believe there may be a new album out this year and a DVD fairly soon from JB and a desire to play live a lot more apparently...this was the first time for 32 years he has come to australia, so a real treat...great band, great sound. One wonders how he remains so lean and unchanged in many ways after all these years, even if his music has gone through many variations in that time. pete Link to comment Share on other sites More sharing options...
axxion Posted January 27, 2009 Report Share Posted January 27, 2009 (edited) Alright this is directed to anybody but I bet Mr.PSW could answer this no no time flat. (I hope I got your attention?) I got lost in the many pages of this thread. So I have some REALLY BASIC questions that anyone can answer: 1. I understand the sustainer completely. Now how is the entire unit wired to the guitar itself? I'm just asking for a basic block schematic. Is it wired directly to output?... 2. I have 2 humbuckers in the guitar currently and want to keep that. I'm thinkin of doing a swimmingpool rout on the thing, moving the neck pick up to the middle position, and putting the sustainer in a humbucker cover and placing that where the neck p/u used to be. Am I still going to get uncontrollable feedback if it is wound to 8 ohms?Would having less ohms fix this? OR... what happens when the sustainer is in the middle? I like the idea of keeping the bridge and neck humbuckers as they are and then having the sustainer in the middle. I'm not interested in tearing apart half of the neck pickup to put the sustainer in there. 3. Say I love the sound of feedback. I'm a Sonic Youth monger. Is there anyway I can add a 'booster' in front of the sustainer so as to increase the ohms past 8, and hopefully get some wickedly loud, instantaneous feedback? Somthing like sustainer -> feedbacker 4. What does slanting the sustainer slightly (like a Fender bridge p/u) do? 5. If I use the magnet in the core, do I still need a magnet underneath? Does it matter if I orienent it so that the N side of the verticle core magnet attracts the S Side of the horizontal base magnet, and so on? EDIT: Alright I have a proposition for my own question. (Number 3). Okay so you say the sustainer is only 3 mm thick. What if I had some extra windings underneath attatched to a switch? So when I flick on the switch, it adds those windings to the original number (in series) thus amping up the ohms? Sustainer becames Feedbacker! EDIT: What if you wired the Sustainer hot (like in the 10-12 ohm range) and then put a potentiometer in the circuit? Normally you'd want the sustainer down a bit, around 5-7, but when you wanted more feedback you'd just crank the knob to 10.... What value pot would I use then? Edited January 27, 2009 by axxion Link to comment Share on other sites More sharing options...
psw Posted January 27, 2009 Author Report Share Posted January 27, 2009 I understand the sustainer completely. well then, you are the only one! ok...quick answers for now...others might chip in... #1 there are some wiring things about...maybe in the tutorial. With a single pickup guitar it is all wired in and all you need do is connect the power. Additional pickups are significantly more difficult....usually requiring a 4pdt switch. Basically, you need to connect power and lift the hot and ground to all other pickups...or potentiall the whole selector. At the same time you need to connect the bridge pickup and connect the power. So, bypass other pickups and grounds, power on, bridge pickup selection (in case it was on the neck pickup at the time). There are many variations on how to do this. #2 Don't do any guitar modifications till you have completed tests on circuits and drivers. Moving the HB to the middle position does not sound like such a good idea...better a rail HB or something and a driver next to it in the neck position slot. However, not something to worry about until you have fully tested your skills on the thing...remember a lot of people have failed!!! #3 3. Say I love the sound of feedback. Well...this is for you...this is what it does...controlled feedback...but it can get quite outrageous if you want...my sound clip was absolutely clean and direct so not a good example of extreme kinds of sounds that it can do. However...you appear to be falling into the same trap as others lately and many times before...can you have too much feedback...YES! What you want really is to build a sustainer that will run just below the point of squeal...if you want less, then dial it back...anything more is useless. Mine will do this, particularly on a good battery. 4. What does slanting the sustainer slightly not much...just puts one end even closer to the bridge pickup reducing the sustainer threshold IMHO! #5 no...a magnet as the core doesn't need anther magnet, theoretically. Unfortunately, finding a suitable magnet is near impossible and in practice most of my drivers have worked better with a core and external magnet. There are other factors as well...and more magent strength is not a good idea. The N/S thing doesn't matter too much...for sustain. Flipping the magnet can produce the harmonic effect, but reversing the wires of the driver puts it back...so no problem. However, it can affect nearby pickups as in reinforcing or reducing the pickup field creating slight effects. Possibly reducing the humbucking effect on an HB for instance, or widening the pickups magnetic window that could affect tone a little. Alright I have a proposition for my own question. (Number 3). See #3 above... You do need to understand some of this a bit more...i have posted some of these things recently about coil resonance and speed and what the "thin coil theory" is and why it works. Sustainer becames Feedbacker! see...Sustainer is Feedbacker!!!! That's exactly what it is, nothing more or less. The control and predictability of it is what sets it apart really from conventional feedback. Mine are intentionally a little rawer than some of the commercial units perhaps...but this is something that does seem to be lacking and a short play on a sustainer guitar would soon give you more of a feel for what the thing is and isn't. If you wanted more of an organs kind of sustain...you really need to consider sample and hold kind of circuits. Many digital delays can perform this function...my Boss DD3 or whatever it is has a hold function for instance, clever use of loopers can do it and I saw a roland synth thing do that and more with the new fender V-guitar. anyway...pretty colours there...welcome to the sustainer thread! pete Link to comment Share on other sites More sharing options...
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