psw Posted December 3, 2006 Author Report Share Posted December 3, 2006 Welcome Donut Man...reading this thread can be a health hazzard and is not advised...I recomend people do just jump right in... The piezo thing you are reffering to is Ansils "sustainer mod", piezo under a pickup trick...it is not really a "sustainer" and should be treated as a little suspect. We have discussed it, and I did make it...if it weren't there, I would never have found PG by the way...it came up in my research... You will find the LM386 or it's equivilent...keep looking...it is also made by JVC and several others... The other chips are more conventional opamps and are not suitable...the LM386 is a small power ampplifier. We are exploring other options though, stay tuned...others feel free to contribute. I am in the middle of moving so may be away for a while BTW btw, its great to hear that you're using this thing for real +1... very impressed Is that not just their patent speak obfuscation of "we're using a class-d power amp" ? I think so...I hate patent speak...I think I caught some of it...grrr Judging from what I read yesterday in the Sustainiac patent, I'd say the bilateral driver is the ONLY way to go for a mid position sustainer. Look again, they have proposed other ideas too...I think there are other ideas but the bilateral is appealing... The dual rail driver is MUCH cleaner than the single coil one... what advantage does the bi-lateral design have over bi-longitudinal other than potentially being a little slimmer ? The dual rail driver is also appealing and may also work. Sustainiac put forward the notion that the bilateral is EMI bucking across the strings and not towards the pickups...hmmm...we will have to see about that! There is a lot of misconceptions still by all concerned (especially me)! The current slimline system (like the one you, me and others have built), while fully working, is just too "dirty" - it radiates a lot of garbage into the highly sensitive guitar electrics and is a major source of instability. I am not sure about that...I have made a lot of drivers! The thin coil design was made largely to increase speed and avoid phase problems and circuit corrections featured in other systems. It is also my theory that small profile coils concentrate the energy under the strings and emit less garbage than the substantially bigger coils found in devices like Sustainiac and Fernandes have put forward before. I do believe that it would be wrong to underestimate the thin coil design or the hex very small designs it came from in this regard. I can't see how making it bigger would reduce EMI...but I have been wrong before. Think about coil orientations...one way is to put the coil on it's side...but there are other ways of orienting such a device than at or parralel to the strings...have a bit more of a think...you may come up with some radical ideas...they might not be all that you hoped for however...Here's an example of one of mine from a while back to get you thinking... That has me worried a little too, but on leafing through the Sustainiac patent yesterday, it seems that their system is perfectly happy running mid position with either the neck or bridge pickup selected, although their system is for a fully active guitar. Well the only mid coil sustainer that I know of that exists for sure is Dizzy's ...Sustainiac specifically designed the mid driver for strat type guitars with a lot more space between pickups...that doesn't mean it cant be done...but it will be very tricky and a quantum leap IMHO... My new guitar has a bridge HB SD JB medium hot pickup (like col's) but there is some space between the mid and it and more between the mid and neck. There may be something to spliting the HB coils to drive the circuit...but the whole pickup will still be sensing any EMI...I have some other reasons for thinking this might help... I have made working drivers that are only 4mmx4mm though and it is possible that this type of device could be surface mounted (my new guitar will fit such devices easily under the strings) and work between the neck and mid pickups, but with the bridge pickup only as in our present and the commercial systems...They would take a bit more development however. Also interesting to read yesterday in that patent was their comments about feedback - they talk about induced interference (magnetic coupling - the fizzies) and electrostatic capacitive coupling, something I hadn't considered before. They mention that the way to get around the capacitive coupling is to invert the driver signal so that the the driver and pickup signals cancel each other out. Normal and Harmonic modes are then handled by clever manipulation of the driver signal rather than simply flipping the phase of the driver leads like we've all been doing. I suspect my eyes glazed over at this point in the patent...perhaps you guys could explain this a little more..."electrostatic"? I have tried various means of magnet direction, signal phase reversal and drive reversal...I really should have been more scientific in recording what I did, I regret that often...who would have thought we would still be talking about this project years down the track... Anyway...it's fantastic that your guitar is working and will be picking everyones brains when it comes to building my next model sustainer... (got to get a better preamp with phase reversal before the power amp and will be testing that BTL amp when I get it back... One good thing is that we have working sustainer guitars to mess with. My sustainer guitar was built especially for these experiments...it is fairly easy to replace amps and such. I may even try removing all but the bridge pickup and see how bad present driver is in the centre position... Got to run...take care all...remember me while I am away... pete Link to comment Share on other sites More sharing options...
curtisa Posted December 3, 2006 Report Share Posted December 3, 2006 Is that not just their patent speak obfuscation of "we're using a class-d power amp" ? I think so...I hate patent speak...I think I caught some of it...grrr Not sure. Probably. Like I said, I was only skimming through the patent. It could be something as simple as that, but I was thinking (hoping!) that there was something different happening there. I'll have to re-read the patent, and check through the schematics again. I am not sure about that...I have made a lot of drivers! The thin coil design was made largely to increase speed and avoid phase problems and circuit corrections featured in other systems. It is also my theory that small profile coils concentrate the energy under the strings and emit less garbage than the substantially bigger coils found in devices like Sustainiac and Fernandes have put forward before. I do believe that it would be wrong to underestimate the thin coil design or the hex very small designs it came from in this regard. I can't see how making it bigger would reduce EMI...but I have been wrong before. I'm certainly not discounting the slimline driver It certainly does work, but I do wonder if there is a fundamental reason why the commercial manufacturers of sustainers do not use it - they have all seemed to have gone with much more complicated drivers (dual rail, dual winding, laminated cores, sliding magnetic shields etc), or at least drivers that are expressly used for that purpose (no stacking of pickup/driver). Well the only mid coil sustainer that I know of that exists for sure is Dizzy's ...Sustainiac specifically designed the mid driver for strat type guitars with a lot more space between pickups...that doesn't mean it cant be done...but it will be very tricky and a quantum leap IMHO... Hmmmm...any idea how magnetically shielded speakers are made? You know when you place your hifi speaker too close to a regular cathode ray tube TV and get all those crazy rainbow colours and distorted pictures? Magnetically shielded speakers are specifically designed to avoid this - there might be some design clues in there for us aswell. Also, the Sustainiac patent talked about having a driver with a dual winding - one that is wound directly around the core for the driving, and a second one wound around the driver winding to act as a magnetic shield. Not sure what you'd do with this second winding though - earth it out at both ends? Earth it at one end? Drive it with an antiphase driver signal? It's probably in the patent aswell... I'll have to find a cheap and nasty single coil dual rail pickup that I can trash for the purposes of experimenting... I suspect my eyes glazed over at this point in the patent...perhaps you guys could explain this a little more..."electrostatic"? Noise signals can be induced into adjacent circuits in several ways - one is magnetic coupling, caused by the radiation of magnetic forces directly proportional to the signal (sitting too close to the TV while playing guitar, holding a microphone too close to a power transformer), another is capacitive coupling - any two conductors running near each other exhibit capacitance between them. So if everything is "coupled" to everything else by invisible capacitors, then it's possible for signals to "leak" from one point to another. 99.99999999% of the time it isn't a problem because the capacitances involved are sooooooo tiny, but occasionally it can be a problem, particularly if we're using really high frequencies, really high circuit impedances, or lots of parallel conductors. Electric guitars don't use hi freq's, but will use high-ish impedances (500K volume pots, 16K pickups etc). That's why circuit layouts can be critical in RF circuits or guitar tube amps - poor layout can result in excess capacitive coupling that can cause oscillation, poor response and other problems. Cheers, Curtis. Link to comment Share on other sites More sharing options...
col Posted December 3, 2006 Report Share Posted December 3, 2006 Hmmmm...any idea how magnetically shielded speakers are made? You know when you place your hifi speaker too close to a regular cathode ray tube TV and get all those crazy rainbow colours and distorted pictures? Magnetically shielded speakers are specifically designed to avoid this - there might be some design clues in there for us aswell. afair, magnetically shielded speakers just have plate shields of a material that is a good conductor of magnetic flux - the trick is to contain the flux and guide it back to the opposite pole of your magnetic circuit in a way that avoids any EMI sensitive entities e.g. CRTs, office workers etc. It's pretty easy with speakers because it's already a fairly well enclosed system, the problem with the sustainer driver is that the magnetic field has to extend around the strings, and the magnet/coil must be at least a few mm away, so there is no way to totally contain the flux and still have sustain. It's pretty easy to create a partial shield for a driver, the difficulties are how to know how well your shield is working, and how to get it to work without compromising the efficiency of the system. Also, the Sustainiac patent talked about having a driver with a dual winding - one that is wound directly around the core for the driving, and a second one wound around the driver winding to act as a magnetic shield. Not sure what you'd do with this second winding though - earth it out at both ends? Earth it at one end? Drive it with an antiphase driver signal? It's probably in the patent aswell... Might jsut be an idea they had that didn't work well, but they want to limit their competitors options, so they include it anyhow... I would guess that a second 'exterior' coil would have to have a signal if it was going to do anything (else why not just use a solid shield).... and it would have to have an opposite signal to the interior coil (or reverse winding) else there would be no point in having two coils... but how do you prevent cancellation therefor loss of efficiency. And then theres the fact that you've brought your magnetic circuit closer to the pickup by adding width to it.... The advantage of the bi-lateral driver over the bi-longitudinal one - as Pete suggested - is that it should keep (some of) the flux in a tighter plane at 90º to the strings (from one end of the driver to the other). The dual rail will possibly leak more flux toward the neck and bridge (circuit goes from one side to the other). It would be nice to have one of each driver and some sort of flux density sensor to test them with - all this theory is fun, but you can't beat empirical science There is at least one possible disadvantage to the bi-lateral driver - there must be some loss of drive in the area where the two coils meet. I guess this is partly offset by the fact that the D and G strings don't need as much drive, but its still something to consider.... maybe this loss of drive to the two centre strings is an advantage ? As far as using a laminated core, this should give an efficiency boost because it reduces losses due to eddy currents, although I'm not sure exactly how significant these will be. Its also possible that when produced in bulk it could be cheaper to produce the laminated cores - there must be many factories set up to produce cheap cores for transformers - easy to get them to do a batch of cores for sustainers if your talking about thousands of units - and the same factories will probably be tooled up to wind them and pot them. So we need to try the bi-lateral, but ideally come up with 'a better mousetrap' Link to comment Share on other sites More sharing options...
curtisa Posted December 4, 2006 Report Share Posted December 4, 2006 It's pretty easy to create a partial shield for a driver, the difficulties are how to know how well your shield is working, and how to get it to work without compromising the efficiency of the system. But surely we're only looking to shield excess radiation of EMI from the sides (away from the pickups either side) and rear (away from the control wiring) of the driver, channelling the driver magnetic force forward towards the strings? That would simply require a magnetic shield that cups the driver leaving the top exposed to drive the strings. I would guess that a second 'exterior' coil would have to have a signal if it was going to do anything (else why not just use a solid shield).... and it would have to have an opposite signal to the interior coil (or reverse winding) else there would be no point in having two coils... but how do you prevent cancellation therefor loss of efficiency. And then theres the fact that you've brought your magnetic circuit closer to the pickup by adding width to it.... The patent mentioned it as a cost cutting exercise - cheaper to add an extra winding than manufacture special shields. What if the shield winding was driven by a DC voltage, so that the outer winding is magnetically "biased" towards one pole? Any ideas if that'd act as an effective magnetic shield? As far as using a laminated core, this should give an efficiency boost because it reduces losses due to eddy currents, although I'm not sure exactly how significant these will be. Its also possible that when produced in bulk it could be cheaper to produce the laminated cores - there must be many factories set up to produce cheap cores for transformers - easy to get them to do a batch of cores for sustainers if your talking about thousands of units - and the same factories will probably be tooled up to wind them and pot them. An easy way to get laminations to experiment with would be to take a small power transformer, pull it apart, separate all the lams, and cut and shape them to the new profile to suit the driver. The only trick is to make sure all the lams are electrically isolated from each other (varnish perhaps?), otherwise the advantages of a laminated core are lost. Farnell and RS Components sell transformer kits. Where did that photo essay on dissecting a sustainer go? I looked for it the other day but couldn't find it in this giant thread! Link to comment Share on other sites More sharing options...
custom22 Posted December 4, 2006 Report Share Posted December 4, 2006 OK, the fact that this thread is over 100 pages long is hurting my brain and my eyes, so Im going to ask my questions now I understand that the refined and currently accepted method of the DIY sustainer is using the fetzer ruby preamp, and having it drive a DIY driver, which is a magnet with some wire wrapped around it (see I have been reading) but what i dont understand is, what is wrong with the original design on the tutorial section of the project guitar site? I know that the piezo method doesnt work the same way as the "refined" method, but does it still sustain and acchieve a similar effect? second question, for the method on the site, do I have to use a 386? maplins dont seem to sell them anymore, can i use a LM331N, lm358N or lm393N or anything else I can get from maplins? forgive my noobiness guys Try www.smallbearelec.com Thats where i get my parts. Theres nothing really wrong with the current design; these people are trying to work out different things such as using the sustainer with middle pickups or making a sustainer which cuts off when the note is sustained to save powe. Link to comment Share on other sites More sharing options...
psw Posted December 4, 2006 Author Report Share Posted December 4, 2006 Big psw Post, Part 1 Where did that photo essay on dissecting a sustainer go? I looked for it the other day but couldn't find it in this giant thread! Here you go... German Sustainiac Photos...Link I don't want to sound vain and I know the thin driver is simple, however...this design is fundumentally different from any others patented or otherwise proposed...it works without phase circuitry and due to it's small size, it happens to be able to be used with a pickup, though that was not part of the design brief at all. I'm certainly not discounting the slimline driver smile.gif It certainly does work, but I do wonder if there is a fundamental reason why the commercial manufacturers of sustainers do not use it - they have all seemed to have gone with much more complicated drivers (dual rail, dual winding, laminated cores, sliding magnetic shields etc), or at least drivers that are expressly used for that purpose (no stacking of pickup/driver). I would like to think that the reason that they haven't used it, is they simply didn't think of it!!! In fact I am sure of it and I hope that this very public disclosure will prevent anyone (including me) patenting it due to prior knowledge. I think Col is right that much of the design of the sustainiac is that it is based on simple conventional transformer coils... I also think that most people who have approached this have had in mind a driver in the shape of a pickup and so felt the need to make a device that resembles a pickup. None of my early drivers at all resembled pickups and the thin driver is based on those principles. The thin driver maximises the electromagnetic energy in a small area directly under the strings, it is working on a small area at the very edge of the magnets polarity on a small (and thus fast core)...it is a very powerful coil in that it's thiness maximises the number of overlapping turns. A deeper coil of the same ohmage or turns would have far less overlapping and has not been successful. A laminated or powdered core would be good, ferrite has proved best for me (it is non conductive and has very fast state changing characteristics), but impossible to work with. The thin driver was an attempt of an achievable DIY project afterall...I made far more exotic devices... What if the shield winding was driven by a DC voltage, so that the outer winding is magnetically "biased" towards one pole? Any ideas if that'd act as an effective magnetic shield? This is what I called an "active shield". A static shield would be a magnetic/ferrous material around the coil to focus and contain EMI. I did try fins and such but it had little effect. More substantial shields such as zfrittz6 seems to have successfully utilized... Pete, I think that the fine conductors podrian themselves to use in the single average position a coil but must be isolated of EMI, I I have proven this in my ibanez and works enough or, for it as in other occasions I have used very fine tin strips having surrounded the coil until reaching the size of the average harvesting practically annulling almost all EMI towards the sides and without using nucleus in the single coil with the magnetism of the harvesting, and to thus it has worked me or in the average position and that that evo2 is enough hot in the other guitar which I have has the harvesting lace sensor of fender and placing it until almost a cm. of near the harvesting does not have interferences, I think that deberias to prove it, single is necessary to cut strips of 2mm. of tin of the pepsi-cola and to surround the coil until 0,5cm by thickness with her, and almost is annulled EMI, with the bilateral coil I have not had better results than with which I have put. The "active shield" is an external coil wrapped around the other carrying a signal inverse to the other. It acts in part as a dummy coil or shield as it does not have a core. However, I had some concerns when it was discussed (years ago) that the inner coil would be it's effective core and may adversely effect the drive. More recently when I mentioned it someone suggested that it would only be an extra power drain as you would need to run a signal through the coil for no drive effect. I mentioned it recently because I did wonder iif the coil of the pickup, with very many more turns, could not be utilized in this way at low power to provide some EMI cancelling effect to the driver on top... Might just be an idea they had that didn't work well, but they want to limit their competitors options, so they include it anyhow... All the patents are full of such stuff. Around Page 7 I linked a lot of the patents and have read as many as I could find and the ones referenced by them. I have even found a patent for an electromagnetic sustainer from the 1800's!!! Lovecraft, very wisely suggested that I forget about the patents, and in so doing so, the thin driver and a host of other things were explored, by not following their example... Sure, it is worth consulting and paying note, but we have to be a little smarter and luck out a little with practical experiments and experiences. Far more has been achieved by making these things, than in inspiration or in research. Big psw Post, part 2 The advantage of the bi-lateral driver over the bi-longitudinal one - as Pete suggested - is that it should keep (some of) the flux in a tighter plane at 90º to the strings (from one end of the driver to the other). The dual rail will possibly leak more flux toward the neck and bridge (circuit goes from one side to the other). It would be nice to have one of each driver and some sort of flux density sensor to test them with - all this theory is fun, but you can't beat empirical science Quite right...and Tim's development of a simple jig to make coreless and bobbinless coils will aid in this process... I'll have to find a cheap and nasty single coil dual rail pickup that I can trash for the purposes of experimenting... Fortunately, Shawn/spazzy has donated just such a pickup to the cause and I have it right here... There is at least one possible disadvantage to the bi-lateral driver - there must be some loss of drive in the area where the two coils meet. I guess this is partly offset by the fact that the D and G strings don't need as much drive, but its still something to consider.... maybe this loss of drive to the two centre strings is an advantage ? You will recall that I proposed several ideas that combine both the bilateral and rail style devices... These "split blade" designs have each coil slightly overlapping between the d and g strings. As our coils are far more compact than sustainiacs, this is easily obtainable with a pair of 4 ohm coils. I am concerned about the commonly bent g string ... Unfortunately, these rail pickups are wound with very thin wire and overly hot and don't sound too good as a pickup (to my ears), certainly clean. I am interested to see how it would sound if rewound with more conventional wire and less hot, but perhaps it would not fit sufficient wire on them. I am alos interested in the idea of having half of each coil coreless in an attempt to get a more single coil sound and lessen it's efficiency...the driver coil on top also necessarily lowers the pickup... The other aspect is that the rail magnets, even without the core opposite the driver still are in place and perhaps would draw EMI back into the guitar. I have had similar ideas where powerful but concentrated rare earth magnets deep below the driver could be more of an attractive target for stray EMI that say the pickups...just a random thought... ...capacitive coupling - any two conductors running near each other exhibit capacitance between them. So if everything is "coupled" to everything else by invisible capacitors, then it's possible for signals to "leak" from one point to another. 99.99999999% of the time it isn't a problem because the capacitances involved are sooooooo tiny, but occasionally it can be a problem, particularly if we're using really high frequencies, really high circuit impedances, or lots of parallel conductors. I suspect that this "capcitance" is a major problem and contributor to the fizz. While electric guitars don't run at high frequencies, all kinds of artifacts, noise and distortion can enter our system. The problem (at least on my guitar) is markedly worse in the harmonic mode and the guitar's range into the high frequencies is at least double...it is also driving using the harmonic note as it's source. I am interested in Col's "mixed mode" approach. My lower range is effectively "mixed" due to the low output capacitor value (100uF), it is more predictable than "harmonic mode" and does not suffer quite as much. Perhaps that is because it is working on lower frequencies...hmmm My preamp has filtering of frequencies beyond the range of hearing, but perhaps this is not enough, it may be better than the simple fetzer valve preamp however... The fizz is a distortion/interferance quite different from the squeel of typical feedback oscillation and is the main problem to close driver and pickups. I think someone mentioned...ahhh...here we go, unklmickey...page 146 Pete, if you're not too tired, here's another interesting theory: in most applications driving coils for things like CRT deflection circuits and such, they use CURRENT feedback in the final drive. i am speculating this might be a VERY important avenue for experimentation in the sustainer arena. in it's simplest form, a small resistor is inserted between the "bottom" connection of the coil, and ground. this is used to sample the current through the coil. then through an appropriately sized resistor (to determine gain) this is returned the inverting input of the amplifier driving the coil. if you guys have not already worked in this direction, i strongly urge you to consider this. Ok...so perhaps we were distracted and passed this by...I would need some assistance with this, but the Lace Alumitone pickups that I referenced are also current (not voltage) based devices apparently...hmmm Just a thought if anyone wants to completely change tack!!! Actually, I miss-recalled Unklmickey...I thought he was suggesting a way to discharge the coil in some way to stop the build up of an electromagnetic charge. RG....a long time ago (in real life a respected transformer designer and member at DIYstompboxes) contributed here in regards to my pop problem. He was suggesting that the coil built up a residual charge that discharged through the earth to the amp on switch off...he appeared to have no solution to it...my only suggestion was to leave the circuit on, in an idle mode. Could there be a way to discharge the capacitance in the coils. I can understand how this may occur...capacitors are made of separated plates...our coils, although ultimately connected consist of winds of separated conductors...hmmm There's nothing really wrong with the current design; these people are trying to work out different things such as using the sustainer with middle pickups or making a sustainer which cuts off when the note is sustained to save power. Thanks Custom 22...that pretty much sums it up. There are some quirks and limitations, I suspect that the commercial units are a little more refined, I think that Col's work and stuff CurtisA may come up with along similar lines is a great refinement...the "pop" on switching off of my device bugs me to the point that I rarely turn it off...which is a pity in a way as I'd like it to become an addition to the instrument: a "guitar with a sustainer", rather than a "sustainer guitar"... In the mean time, I have received more bad news today, nevertheless...I will moving anyway this week so if I suddenly disappear, have no fear, I will return... Great work and contributions by everyone lately, I am really impressed and a little in awe pete two parts because it can't handle so many posts in one...grrr Link to comment Share on other sites More sharing options...
Radiotrib Posted December 4, 2006 Report Share Posted December 4, 2006 Hi. I'm a noob, and a lurker up to now, and this amazing thread goes pretty much over my head .. I've read most of the thread over the past 4 days (or at least - those bits I understand backwards from now to around page 70) but it all gets a bit mind-boggling after the second day !! so I hope you don't mind if I jump in with a dumb question or two ... I'm part way through designing a piezo bridge, and I think a sustainer driver might be an interesting optional addition so ... Do you think that there still be problems with the driver interfering with piezo pickups the way it does with the mag pickups? Secondly, does a separate, self-contained, e-bow type, pickup/driver system need to have a pickup/driver pair per string, or could it be made to work like your current designs using full-width coils for pickup and driver? Would there be any downside to the "wide e-bow" approach to offset the fairly obvious upside of minimizing feedback/hum/fizz loops in the rest of the system? Link to comment Share on other sites More sharing options...
Primal Posted December 4, 2006 Report Share Posted December 4, 2006 The driver shouldn't affect a peizo pickup at all. The feedback is entirely electro-magnetic in nature. The driver creates a massive magnetic field when it drives strings (it takes a hell of a field to drive strings, in comparison to the field a pickup produces). The feedback is just electro-magnetic interference between the driver and the pickup (in fact, in my setup, it seems to vibrate my bridge pickup microphonically when turned up too high, despite it being potted -- either that or its actually vibrating the entire pickup assembly). Link to comment Share on other sites More sharing options...
col Posted December 4, 2006 Report Share Posted December 4, 2006 Hi. I'm a noob, and a lurker up to now, and this amazing thread goes pretty much over my head .. I've read most of the thread over the past 4 days (or at least - those bits I understand backwards from now to around page 70) but it all gets a bit mind-boggling after the second day !! so I hope you don't mind if I jump in with a dumb question or two ... I'm part way through designing a piezo bridge, and I think a sustainer driver might be an interesting optional addition so ... Do you think that there still be problems with the driver interfering with piezo pickups the way it does with the mag pickups? I would guess that using a piezo pickup would sidestep the EMI issues - the reason we are battling to use the sustainer with normal pickups is because we want to sustain a traditional guitar sound... Secondly, does a separate, self-contained, e-bow type, pickup/driver system need to have a pickup/driver pair per string, or could it be made to work like your current designs using full-width coils for pickup and driver? An ebow can only sustain one string at a time. Afaict, the only significant differences between the ebow and our sustained system are that it is held above the strings (only really effects practical usage) and that only trying to sustain one string means only needing one sixth the drive - this means that the driver and pickup can be much closer without all the parasitic interference and feedback issues causing problems. Would there be any downside to the "wide e-bow" approach to offset the fairly obvious upside of minimizing feedback/hum/fizz loops in the rest of the system? Yep, if you make a 'wide' ebow, you basically have our system but handheld - so the downside of minimizing the feedback/hum/fizz etc is that you're not minimizing it at all ! The folks that designed the ebow had a 6 string version patented - this never reached the production stage - I wonder why ??? Col Link to comment Share on other sites More sharing options...
psw Posted December 4, 2006 Author Report Share Posted December 4, 2006 Hi Radiotrib and welcome to the sustainer thread... I've read most of the thread over the past 4 days (or at least - those bits I understand backwards from now to around page 70) but it all gets a bit mind-boggling after the second day !! so I hope you don't mind if I jump in with a dumb question or two ... You must have missed the health warning about trying to read the whole thread...this is seriously not advisable as it will only confuse people more...feel free to jump in... I'm part way through designing a piezo bridge, and I think a sustainer driver might be an interesting optional addition so ... Good for you... Do you think that there still be problems with the driver interfering with piezo pickups the way it does with the mag pickups? No...as Primal says...the piezo's pick up vibrations while the driver uses electromatic forces. The problem is with pickups that sense electromagnetically as they will sense the EMI coming out of the driver if it is too close to the pickup... I believe curtisa tested his driver with an electro-acoustic with some success (beware of bronze strings that don't have the same magnetic qualities of electric guitar strings...) Another member was building a solidbody piezo guitar with a sustainer (I am not sure what happened to that project) So...you could use your piezo's and it's preamp as the source for the sustainer. You may wish to consider a second battery as the sustainer can use a bit of power and this could affect the performance of the piezos... I would suggest that before going too far down this track or getting too experimental, you make the driver and amp and try it out on a piezo equiped acoustic... Secondly, does a separate, self-contained, e-bow type, pickup/driver system need to have a pickup/driver pair per string, or could it be made to work like your current designs using full-width coils for pickup and driver? The sustainer is effectively a big fixed ebow! As the guitar already has pickups, it uses these to source the signal and a driver that covers all the strings. You could make a pickup (a lot harder) to source the signal... Would there be any downside to the "wide e-bow" approach to offset the fairly obvious upside of minimizing feedback/hum/fizz loops in the rest of the system? Ah..."fairly obvious upside of minimizing feedback/hum/fizz loops"...not so obvious I am afraid. The driver and most pickups (not piezos) are electromagnetically connected, even if the sytem has it's own dedicated pickup. Also...you can play all the notes on the guitar but be aware that the sustain tends to be on the lowest note played, fine with lead work of drones below some noodling (all cool stuff) but it wont sustain a chord like a string orchestra or organ or something. I will sustain the lower note of a chord or sound the lower note as an octave above or within a chord. It is not effectively six ebows. Even if you did make six pickups and driver pairs, there would still be some crosstalk between them and the amplification and power requirements would also be multiplied by six so not ver practical I am afraid. Anyway...an interesting project for sure. I did some experimenting with various piezo bridge ideas of my own and will be looking forward to hearing about yours and your progress with the sustainer, should you decide to go ahead with it. Just to repeat though...make the circuit and driver and test it on an electro-acoustic or similar...you may nedd a little tweaking to smooth out high frequency transients with acoustic instruments and it will not work properly with typical acoustic strings... Welcome aboard... pete Oh...and welcome back Primal...have you fixed that guitar again? I appreciate your input and as someone who has successfully built the thing, it is most valuable... p Link to comment Share on other sites More sharing options...
col Posted December 5, 2006 Report Share Posted December 5, 2006 (edited) news update.... I've made a few changes to my installation... Tweaked mixed mode 1 - it now gives a much more distinct harmonic. I think after making this change that it may be worth having a pot for this mode. It _seems_ that tweaking the frequency of the change from harmonic to normal mode not only alters where harmonics start being introduced, but also which harmonics will be introduced. This makes sense because it works by altering the phase of the input signal, so any note above the 'crossover' frequency will not be pushed to its harmonic, this includes harmonics themselves.... meaning that the 'crossover' frequency is also (related to) the maximum harmonic note. Thats why mixed mode doesn't give the excruciatingly high harmonics of full harmonic mode - those seem only to be limited by the rest of the system. So if the pot works it could give the kind of effect that you can with real feedback when you move around and change the angle of your guitar to change the feedback note - instead you would tweak a knob on the guitar to pull out different harmonics..... Added mixed mode 2 - this seems like it is at least useful enough to be worth adding, What it does is give a similar effect as full harmonic except the lowest notes - low frets on the (E A and D strings) stay as fundamentals... so if you hit a chord, the bass of the chord keeps sustaining, but the higher frequency content morphs in a similar way to full harmonic mode. Added a seperate power switch - with a 'no-drive mode' on the rotary switch, pops are reduced further, there still seems to be a little switch noise... could be due to dodgy switches, but it seems o depend partly on what the guitar is plugged into ! I think it is a weaknedd of the design of the circuit - if there is any difference in dc level between the current mode and the wiring/components in the mode to be switched to, there is a faint click. This can probably be dealt with with a few high value resistors though - will give it a try if I start getting annoyed by switch noise... Anyway, having a seperate power switch seems to make sense, and it opens up more positions on my rotary switch (which now only needs 2 poles instead of 3). Back to harmonic modes: The success of the new harmonic mixed mode makes me wonder (ooooo and it makes me wonder), it might be possible to set up two all pass filters to create a phase 'bandpass' style filter... so that notes below and above the pass band will stay as fundamentals while notes within the band would be morphed to harmonics - you would of course have a knob to control the position of the band This would involve some slightly more complex circuitry so I couldn't add it to my current board - it may require 2 pole all-pass filters instead of 1 pole, and also possible a buffer to invert the phase... so it would be more op amps - but worth experimenting with, and if anyone was to make an smd circuit, this idea might be worth considering. EDIT: thinking about it, it would probably need more than 2 pole filters... the transition from 0º to 180º of the all-pass filters is just not fast enough to go up then back down with in a usable frequency band back to reality I'll post some new sound clips and updated schematic and layout asap. Col Edited December 5, 2006 by col Link to comment Share on other sites More sharing options...
lemko Posted December 5, 2006 Report Share Posted December 5, 2006 Hey guys -- I've been trying to build a sustainer-ish guitar for a few weeks now, without much luck, and just discovered this thread; looks like you can probably help. I started with the stock pickup in a thrown-away Mexican Strat, and rewound it with some thin, insulated copper wire I had lying around (I'm not really sure of the gauge). That's basically all the "building" I've done, and it clearly hasn't been enough. I want to be able to drive the strings from external sources as well as feedback, so I tried just using headphone outs on amps and stereos; nothing. A cranked stereo can drive it very, very feebly, and since the pickup isn't potted, it basically just ends up being a really horrible, really weak speaker, although it drives the string enough that I can feel it slightly and sometimes hear it. I did get great results from a 150-watt amp, just before melting the sustainer pickup a bit -- had to make a new one. This time I only used three pole pieces, just in case the problem was that it wasn't concentrated enough; but the results were hardly any better, a barely noticeable difference. So what am I doing wrong? Seems like there must be a much larger difference than I thought in the construction of a normal pickup and a sustainer, much more than just rewinding it to change impedance; what is it? Pole pieces? Magnets? Thanks a lot, Kenji Link to comment Share on other sites More sharing options...
col Posted December 5, 2006 Report Share Posted December 5, 2006 Hey guys -- I've been trying to build a sustainer-ish guitar for a few weeks now, without much luck, and just discovered this thread; looks like you can probably help. I started with the stock pickup in a thrown-away Mexican Strat, and rewound it with some thin, insulated copper wire I had lying around (I'm not really sure of the gauge). That's basically all the "building" I've done, and it clearly hasn't been enough. I want to be able to drive the strings from external sources as well as feedback, so I tried just using headphone outs on amps and stereos; nothing. A cranked stereo can drive it very, very feebly, and since the pickup isn't potted, it basically just ends up being a really horrible, really weak speaker, although it drives the string enough that I can feel it slightly and sometimes hear it. I did get great results from a 150-watt amp, just before melting the sustainer pickup a bit -- had to make a new one. This time I only used three pole pieces, just in case the problem was that it wasn't concentrated enough; but the results were hardly any better, a barely noticeable difference. So what am I doing wrong? Seems like there must be a much larger difference than I thought in the construction of a normal pickup and a sustainer, much more than just rewinding it to change impedance; what is it? Pole pieces? Magnets? You're not doing anything wrong, it seems like all those who started on this road have similar first results... To help you get there faster, you can learn from those others experiments and mistakes. According to Pete and others, the guage of the wire is pretty important, you need winding wire at about 0.22mm. This is important to get an efficient driver - if the wire is too thick, you need way to much bulk to get the right impedence, and your magnetic field will not be focussed enough... if the wire is too thin, there won't be enough to drive the strings, and you will lose a lot of energy to heat. Using 0.22 wire and winding to about 8ohms, you can get a good sustain with an amp producing about 1watt of power. Take a look here for a simple driver circuit and instructions for makeing a driver - not the only way to go, but one that does work and is a good starting point for your experiments. good luck Col Link to comment Share on other sites More sharing options...
psw Posted December 5, 2006 Author Report Share Posted December 5, 2006 Welcom Kenji...it is a big thread and I don't expect you to read it... So what am I doing wrong? Seems like there must be a much larger difference than I thought in the construction of a normal pickup and a sustainer, much more than just rewinding it to change impedance; what is it? Pole pieces? Magnets? A sustainer driver is not a pickup! Wire is important, as col has said much experimentation has shown that 0.2mm wire is the magic guage. Also, I advocate a thin driver fro various reason...a design of my own. Some of those reasons are that it maximises power through overlapping winds (it is only 3mm deep) and speed (smaller core. The main reason is that it has been proven to work! Other's may have made their own sustainer but this is the only place where you will get support and encouragement and full details and proof of the basic design and concepts... As well as the tutorial link that col posted...here is a link to a pictorial of my sustainer design...psw's driver pictorial Also, check out the sounds page for the type of things the device can do...Sustainer Sounds Link Of these I would suggest this clip from me as indicative of the devices range and potential...Beckistan...but ignore the production qualities... Of recent developments in these pages...we are developing the bsic driver and circuitry to a more refined design. Better and more refined response, better power consumption, more efficient dual core drivers... Col is at the forefront of this design process and his circuitry seems to be fast outstripping the potential of the comercial units it would appear. He uses a dual coil driver similar to a rail pickup but with only 2mm coils. Good work BTW col...I am really excited by these developments...I just can't see how I am to get it in the guitar...but, I so want to ! So...a lot of the recent discussions on this thread have been about how to improve the DIY sustainer. The basic sustainer is still a very valid instrument and in the least worth experimenting with. If you have already stripped out a single coil, I suggest that you block up the bottom half of the driver to leave a 3mm space at the top to wind an 8 ohm coil. Use a very small battery amp (do not use hifi or guitar amps to drive it). You can experiment by holding the driver above the strings ebow style until you are ready to install it. You can then experiment with improvements in drivers and circuitry...maybe come up with some stuff of your own. All we ask is that you share in your developments so that we can all learn and bring the project further still. There is some diversion of the direction each of us wish to take it at present. I'd like to try to make a mid driver...there are special problems associated with this. I would also like to add a little refinement to the basic sustainer idea. What col is working on is a new level of control that is very exciting... So, welcome again and I hope we can help you help us in the quest for a better DIY sustainer... pete Link to comment Share on other sites More sharing options...
Radiotrib Posted December 5, 2006 Report Share Posted December 5, 2006 Thanks all for your replies. I'll certainly be considering taking this further as my build progresses. I may not have expressed myself too well previously so to clarify ... My expression "wide e-bow" was meant to describe a dedicated pickup/driver pair rather than a hand-held device. I'm considering a rather radical fretless bass with a set of piezo bridge saddles AND a mag pickup (probably a humbucker) at the Musicman sweet spot. I was considering adding a pickup/driver at the neck end of the body, in order to keep the sustainer de-coupled from the rest of the electronics. With bass strings being nice and fat, with a lot of nice juicy magnetic material in them, and running at a low frequency,they may well take much less energy to get them going .. and .. well .. etc. etc. etc. I'm not worried about building the pickup. I've already got a couple of odd ideas I want to try out sop that I can get rid of a few of the 200 1/4 x 1/16 inch neodymium discs I bought recently .. but that's another story eh? Thanks again .. and now I think I'll drop back into lurk mode while I design and build that bridge ... Cheers, K4 Link to comment Share on other sites More sharing options...
col Posted December 5, 2006 Report Share Posted December 5, 2006 My expression "wide e-bow" was meant to describe a dedicated pickup/driver pair rather than a hand-held device. I'm considering a rather radical fretless bass with a set of piezo bridge saddles AND a mag pickup (probably a humbucker) at the Musicman sweet spot. I was considering adding a pickup/driver at the neck end of the body, in order to keep the sustainer de-coupled from the rest of the electronics.... The problem is that most of the parasitic coupling between driver and pickup is via electromagnetic and electrostatic fields - so it doesn't make a huge difference if you use a seperate pickup for the sustainer and isolate the sustainer system with its own earth etc... if its in the same spacial position in relation to your main pickup there will still be crosstalk via these electromagnetic fields.... it's mind-expanding stuff For what its worth, I have tried using a seperate pickup just for the sustainer. I still had all the usual problems - plus the new one of finding space for the extra pickup. Col Link to comment Share on other sites More sharing options...
col Posted December 5, 2006 Report Share Posted December 5, 2006 (edited) Here's an updated layout and schematic ................................................................... switch connections: e is the output from the input buffer/amp d is the input to the mode op-amp the mode connections are as follows: normal e connected to a1 d connected to a2 mixed 1 e connected to c2 d connected to c1 mixed 2 e connected to e2 d connected to e1 full harmonic e no connection d connected to b1 ...................................... Notes There now should be 38 track cuts, so count them and find the hidden ones you missed You might find that its a bid of a squeeze getting all the components to fit together on the board - thats one of the problems of trying to minimise the footprint - it is possible to get it all to fit without extreme measures as long as you use sensible component sizes. I switched the 1u cap (C5 on the layout) to a tantalum, and it did seem to improve things ever so slightly, but don't worry its not a big difference - could just have been my imagination. ...................................... Mods as before plus - remove R29 and connect a 50k pot in its place - this _may_ give control over which harmonics are generated by mixed mode 1... as yet untested. OK, now the schematic I changed a resistor in the feedback for the input op-amp... the rest of the changes are the mode switching - I used a 2 pole 6 way, with its stop ring set to only allow 5 positions position 1 is no-drive, 2 is normal, 3 is mixed1, 4 is mixed 2 and 5 is full harmonic. here it is Edited December 5, 2006 by col Link to comment Share on other sites More sharing options...
col Posted December 6, 2006 Report Share Posted December 6, 2006 Update: I tried using a pot to control the crossover frequency of mixed mode 1. It didn't work well enough to be worth keeping. Might be worth having trimmers for that and for the same purpose in mixed mode 2, but only if theres plenty of room in your install The reason it doesn't work as well as I'd hoped is because mixed mode 1 chokes the lower strings - and this becomes more apparent as you raise the crossover frequency. My best guess at why this happens in mixed1 and not in full harmonic is that those lower notes don't get a full 180º phase shift, that would bring out the harmonics... instead they get about 150º to 160º which just chokes the fundamental without bringing out harmonics. With mixed1 set to give nice lively harmonics the first octave of the guitars range gets slightly choked - still ok for rhythm stuff) Forget about that though - this thing ROCKS I've spent the last hour or so playing with it, and having the mode switch really makes a huge difference. Each mode has strengths and weaknesses, but the real fun is switching between them while playing - using mixed1 to bring out a harmonic, then back to normal mode... the sound slowly morphs around.... then mixed2 to mixed1 while playing slow legato with the left hand... morph city. The switch noise is not a big issue, the vibration of the physical click of the switches causes more noise than the electrical contacts... here are a few shots I took with my new phone driver1 driver2 driver3 cavity1 cavity2 diy inter8 weave wire pickup and driver controls - small chrome switch and chicken head are on/off and rotary selector The plectrum is in the cavity for scale - you can see that the circuit is big, but not too big cheers Col Link to comment Share on other sites More sharing options...
psw Posted December 6, 2006 Author Report Share Posted December 6, 2006 WOW... That circuit isn't really that big is it, well done... I have not time to go through a long appreciation, but the biggest endorsement is how much you are enjoying it. I love the morphing thing...with a developed sustainer techinque a whole new sound may be possibe. Is that your guitar's actual control cavity, or has it been enlarged? I have been looking at ways to enlarge control cavities by using a router to undercut along the edges. The backplate would be the same size, but the hole larger...could add a bit more space to my strat. Perhaps I could even route out the jack plate some how and join the two cavities. If the battery could find a home in there of in the spring cavity, I may well get a circuit like yours in there (at a pinch)... Meanwhile...the move is on, and I'll be off for a while...glad I caught this when I can and hope to hear some clips when you can put something together...and I am back on line... take care and wish me luck...I really need it, things are not going at all smoothly... pete Link to comment Share on other sites More sharing options...
zfrittz6 Posted December 6, 2006 Report Share Posted December 6, 2006 (edited) Here this the circuit of COL in smd. that seems to you? salu2. Edited December 6, 2006 by zfrittz6 Link to comment Share on other sites More sharing options...
col Posted December 6, 2006 Report Share Posted December 6, 2006 (edited) That circuit isn't really that big is it, well done... Thanks , I don't think it could be made much smaller with standard through-hole components, but it is reasonable - if you were to use low profile capacitors and/or tantalums, it should fit in quite a few different guitars. I have not time to go through a long appreciation, but the biggest endorsement is how much you are enjoying it. I love the morphing thing...with a developed sustainer techinque a whole new sound may be possibe. hehe, I hope I wasn't going overboard. It's just the different modes producing different charicteristics. With a bit of practice and experimentation, it should be possible to get a good understanding and control over the sound while still keeping the organic quality and unpredictability. Is that your guitar's actual control cavity, or has it been enlarged? I have been looking at ways to enlarge control cavities by using a router to undercut along the edges. The backplate would be the same size, but the hole larger...could add a bit more space to my strat. Perhaps I could even route out the jack plate some how and join the two cavities. If the battery could find a home in there of in the spring cavity, I may well get a circuit like yours in there (at a pinch)... Yes, that is the original cavity for my guitar - plenty of space. I think that the company also produced some active models, and the fact that theres a battery sized section in mine suggests that they may have had a standard cavity template... who knows. Anyway it certainly is an advantage for this type of project. I don't have to really plan anything - as you can see the lead dress is pretty messy. I guess undercutting the cavity on a strat would be an option, although I'd be worried about weakening it, and also about changing the balance of the guitar. We still haven't looked into the cost of small runs of smd circuits - worth some investigation I think. Meanwhile...the move is on, and I'll be off for a while...glad I caught this when I can and hope to hear some clips when you can put something together...and I am back on line... Good luck with the move - fingers crossed there won't be any last minute hitches. I'll try to get some more demo examples up soon to take your mind off things Here this the circuit of COL in smd. that seems to you? looks good. some questions: Are those surface mount resistors and caps ? what about a surface mount j201? anything to reduce the size would be good I think, I'm not sure that there's any point going surface mount without making it as small as possible what about a double sided board when it says 3cm x 2cm is that for each half or for the whole thing? and is it for just the circuit, or the whole 'black' area ? thanks, col Edited December 6, 2006 by col Link to comment Share on other sites More sharing options...
psw Posted December 7, 2006 Author Report Share Posted December 7, 2006 hehe, I hope I wasn't going overboard. It's just the different modes producing different charicteristics. With a bit of practice and experimentation, it should be possible to get a good understanding and control over the sound while still keeping the organic quality and unpredictability. No, no...it sounds like you have got more of what I am looking for from the device and in some ways taken it further than that of the commercial guys....S&F Here is PDF of the kind of thing that could undercut a cavity to make it slightly bigger... Kinman Undercut PDF...you use a router to cut around the edges...I doubt that this small enlargement would do much to the balance and would allow for a bit of circuitry or better switch placement perhaps...anyway, the additional battery adds some weight! It is only really appropriate for guitars like my new one I suspect where the cavity has a flush fitting cover and routing out and risking the finish as well as making a new cover...with a conventional strat and may others, the pickguard could hide a multitude of sins and may wouldn't think twice about routing out a thin cavity for your circuit under there... Good luck with the move - fingers crossed there won't be any last minute hitches. I'll try to get some more demo examples up soon to take your mind off things It might take a bit more than that, I lost the house again, this time in the middle of the move. It had some major faults as it turned out and the landlord and agent were acting very badly...had to terminate the lease on the day of moving. Very distressed and a little expensive...everything is in boxes for the move again...I really don't seem to have any luck at all, I don't even feel like taking stuff out again...maybe I wont! Anyway...the circuit looks great and appears to shrink down just fine. Even the conventional size would fit in a Les Paul I suspect (you'd have extra knobs to play with too ) Easy battery access may be more of an issue...you were lucky to find a cavity made for it. A two spring trem would allow space between them. On a single pickup guitar, or if the mid driver idea worked, the top mounted box/tailpiece idea may work, or something that replaces a strat's jack socket with the baterry down the hole may be considered. With all this stuff going on, I have not been able to play my new guitar...so, to sooth the nerves I got to blow out a few riffs...oh what a difference a good guitar makes. The sustain of this guitar is great compared to my hollowed out strat...very smooth with the JB HB, single coils are a bit noisy and disappointing, but hey it's a squier. A few of the switch options could sound better...combining the middle and bridge HB is disappointing, the middle and neck is nice and the neck ok (considering the quality of the pickup). I actually prefer the sound of my driver/pickup ceramic blade pickup much better...so much for the alnico myth. Perhaps there are better sounds to be coaxed from it with some custom wiring. Taping the HB with other pickups might be nice and a neck/bridge combination is ususally good. There is a nice sound with the tone down on one pickup with the neck/middle combination. So if I had to loose the middle pickup, it wouldn't be too bad. The HB is a little too smooth compared to the strats, but perhaps I need to redo my settings to get the best from it... For all that, it is missing the "aliveness" of the sustainer guitar. The neck though is great...still strung with lighter strings than I would like and only two springs in the two point trem (I like it a bit stiffer than that) but it plays really well. So...will still be around a bit but now it is off to find yet another house... pete Link to comment Share on other sites More sharing options...
zfrittz6 Posted December 7, 2006 Report Share Posted December 7, 2006 Everything is for superficial assembly, and in double slide, + of the circuit and the negative as well as points 1--1 up to 5---5 go united from a face to the other, in addition 3cm x 2cm is of each one of the sides, it is possible still to be done but small but with system DIY to make serious the plate complicated because the tracks are united or they cut when they are tried less of than 0.012 of thickness, I am mounting it and when it has pondre photos. Pete I feel much everything what this happening I hope that it soon to you solutions, a friend. greetings. Link to comment Share on other sites More sharing options...
psw Posted December 7, 2006 Author Report Share Posted December 7, 2006 Pete I feel much everything what this happening I hope that it soon to you solutions, a friend. Thankyou...one day soon something will happen...I really appreciate your concern and for letting me mention it from time to time... My daughter made a saying up tonight, I was worried about how she would take it as it means a lot to her to spend some time with me and this would have mean't a lot more..."Think Small, but walk Tall", meaning keep your chin up and take one step at a time...I love her, she is an inspiration... Of course, playing the violin, she doesn't need a sustainer...perhaps we should just make a little bow and drag it across the strings...'course the rosin makes a mess...hehe Thanks guys... pete Link to comment Share on other sites More sharing options...
col Posted December 7, 2006 Report Share Posted December 7, 2006 (edited) Added a new demo, this time its a droney distorted harmonics type of thing. Its a bit messy in places, so sorry aobut that, but it does give some idea of what might be possible with a little planning and practice Also demonstrates that it's possible to get a reasonable guitar sound through pc/headphones with just a few diy devices and some midrange pc audio recording software. go here (couldn't get the damn auto-link to work) http://www.soundclick.com/bands/pagemusic.cfm?bandID=602062 Col Edited December 7, 2006 by col Link to comment Share on other sites More sharing options...
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