col

I suggested something along these lines a while back, although the idea wasn't as well described due to my hazy understanding of the concepts, I basically had a hunch .. I tried to explain it in relation to how the driver and pickup were connected via the earth.. either in phase or out of phase.... Anyway, I have not been switching the driver leads to get harmonic modes... instead using a buffer to invert (or not) the signal... the mixed modes are achieved via a simple all-pass filter. Is that not just their patent speak obfuscation of "we're using a class-d power amp" ? have they got some sort of trick in a custom class-d design that gives the equivalent of AGC? treating the PWM signal in some way? 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. 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. 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 ? btw, its great to hear that you're using this thing for real Col

Yes, I think a seperate power switch is important. Ideally we can have one of the modes as 'no drive' that can be switched with no click or pop - it would still use power, but not very much. I have simulated the second mixed mode, and I can squeeze it onto that board, but I've not tested it so I don't know how good or useful it will be yet. If it works out, the new setup will be a 5 way rotary switch with: no drive normal mixed 1 mixed 2 full harmonic and a seperate on/off (this could just be the guitar jack if you wanted to always have sustainer, or alternatively a toggle or slider switch, or a push/pull section of a fancy pot... While this may be true...SMD for one off construction can be very expensive... If we got a few people together, we could probably sort out some sort of small batch from a manufacturer - however I wouldn't want to even think about going that way until the circuit is totally functional, debugged and tested by multiple people on different setups. I may need further assistance translating the translation ...I would appear that zfrittz6 has been able to get it working in the middle (average?) position with the single (fine?) coil design if magnetically shielded by layers of metal to 5mm surrounding the coil...and that the bilateral is no better. While I never went to the extent of putting such a massive shield around any of my designs, I am surprised that the energy from the driver doesn't travel down the metal strings to be picked up by the source (harvesting?) pickup only 1 cm away! Still, perhaps it can be done this way. One concern I have is that in my experiments with shields, I found that they reduced the drive somewhat... I think the shield tends to channel the flux not just away form the bad places, but also away from the strings. I guess the trick is to get the correct balance between enough shielding and enough driver efficiency... or move to outboard power. It's possible that sustainiac had a mid position system working, but decided that on balance, it was not such a good product. It would require more power to give the same level of drive, and it would also be much more sensitive to small variations in guitar setup and hardware. You also have the issue of the big chunky shield - how do you make that stylistically acceptable to the market... And then of course there are the reports that the harmonic modes don't work the same with a mid position driver - although I'm not sure why they wouldn't.... Still thats all conjecture - I want to hear more about your shielded driver zfrittz6, does it use more current to get the same drive level? does harmonic mode work? any pictures would be good to see as well Col

watch out for at least one fairly obvious error - I noticed that it's pencilled in on the print copy I used as a reference when building my board... there should be another track cut at 'b 27' - or pins 1 and 3 of the output pot will be shorted together. oops... I'll post a corrected and updated layout soon - will add 'mixed mode 2' to that if testing goes well. Col

I've uploaded the circuit to photobucket - it should be ok, but if there are differences between it and the layout (other than slight component value differences) better get back to me. One thing to note is that the mode switch is a 4 way, it should really be a 3-way, but there wasn't one Col

Here's the strip board layout for my latest circuit revision - fully tested and working Pay particular attention to the 'cut track' symbols - red dot in red square - some of these are hidden under resistors and only just visible there should be 35 of them. Look carefully for partially hidden blue jumper wires there should be 12 in total Note also that this is the preamp only - the output should be connected to a LM386 poweramp section (refer to my old LM13700 circuit and use the 3rd part of the 3 part strip board layout) ................................................................... 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 e connected to c2 d connected to c1 full harmonic e no connection d connected to b1 ...................................... According to the notes for the limiter shematic I used as a starting point, C5 should be either a tantalum or a low leakage electrolytic - a standard electrolytic will not be good enough. I have tested the circuit with a normal electrolytic and it seems to work ok. I have also just obtained some tantalums to try... I'll post if a tantalum cap improves the response in any way. ...................................... Stuff to tweak: R5 : increase this to allow a higher maximum threshold setting (and a higher minimum) R29 : controls the frequency at which the mixed mode changes from normal to harmonic reduce the value to have more harmonics further up the neck. (tweaking C8 will also effect this setting, again, lower for more harmonics) ....................................... possible additions: 2nd mixed mode this would be normal mode for the lower frequencies, blending to harmonics for higher notes... basically the inverse of the current mixed mode. I have found that having the power switch on the same rotary switch as the modes causes a click when changing mode, so I will probably have a seperate power switch - at which time I will see if mixed mode 2 is a worthy addition AGC bypass You may find that you really miss the wilder feel of the normal fetzer/ruby based circuit, it should be fairly simple to rig up a switch to bypass the AGC section of this circuit in order to provide similar functionality. so anyway... here ya go: I'll post the updated schematic soon as well.... as soon as I've worked out a sensible way to show a 3P4T switch.

The only way to avoid using electrolytics that I can see is to use Tantalums instead - they are much smaller, but DAMN expensive cheers Col

Maybe, although these days my feeling is that electric guitar is more traditional instrument. In the 50s and 60s, the solid body electric gutar/amp combo was still a new phenomenon, the modern equivalent it probably something like real-time performance sampling using loops and 'glitch' based effects, granulizers etc. to create extreme and challenging sounds. I guess if you went the whole way it could be interesting. A guitar that's not a guitar - i.e. doesn't have any real natural sustain, doesn't have any traditional pickups (piezos or some such). Just a plywood plank with frets and purely cosmetic body 'wings'. It would have a power lead and a signal cable. And of course a sustainer - on all the time. For years luthiers have strived to produce guitars with full sound and warm sustain but a sustainer guitar may work better with little or no natural resonance from the neck and body.... Don't forget the depth of the circuit - those components can be quite tall. Until we get a fully optimised thin (like sustainiac) smd based circuit, I fear that some folks are going to have to work on board layouts custom designed to fit the available spaces in their guitars. Col

My stripboard layout is about 3cm x 7.5cm, so you have certainly improved upon that There are a few extra components for the mode switching - just 4 resistors and a cap, so shouldn't make much difference to the size. Col

I did get the impression that you were partial the the more extreme end of Sustainville I have played with this unrestrained system myself, and it is somewhat envigorating. One thing you might want to consider is to have a system where you can switch between AGC and non-AGC versions. So you can choose depending on the situation. I think that you are going to have huge problems trying to get a non-agc system to work in the middle position - as you increase the drive, the EMI obviously increases as well, and additionaly have more clipping to contend with. I had another listen through your demo clips, and many of them have extreme settings with fret buzz and loads of sustainer generated fizz and fuzz. I agree that when this is used to advantage it can add to the character of the effect, but it also limits the usefulness and applicability of the system. If you were using an AGC setup, you might want to stick a compressor in the chain after the guitar to bring the sustained level up higher - although its pretty good as it is and even mild crunch will level things right up. Maybe the best approach if you want a really hard sustain, would be to have an AGC to keep it just below the level where you get fret buzz, and power it from an off board 18V supply with an amp a bit more powerful than the LM386. I guess the main thing though is that the two approaches are quite different. I think once you have tried the AGC system, you will appreciate it for what it is. It is more subtle, and can be used to enhance all your existing chops without overpowering them and requiring a change of technique. If you are intent on spreading the word and getting the whole guitar world into sustainers, I think the AGC approach will have more success. Personally, I would like to be able to have more extreme settings, but I'm not sure that it will be practical in a 9v battery system - maybe we can get it happening with a class-d driver amp. Thats cool zfrittz. One thing to note: The circuit has changed since it was posted, it now has a much better mixed mode setup. I'll post an updated circuit soon, so you can update it. btw, what is the size of this pcb? Thanks Col

It is quite a strong sustain, but with a very clean pure sound. It is possible to make is a little stronger, but the stronger you make it, the quicker it takes over from the natural guitar sound. All things considered, I prefer it where it is. Of course, at this setting it's still powerful with some distortion in the sound .... There's also the option of adding a compressor into the signal chain, but I don't think that will make much difference really. And in adition, the louder you make the sustain 'effect', the harder you push the battery, so it runs out sooner, and it also is more likely to get 'tired' when you push it really hard. I think with a clean sound the harmonic effect is subtle. With distortion these harmonics are brought right up. It is an interesting sound though to have notes fade out into a harmonic...a very subtle little detail, but nice all the same. Perhaps it does need a little more power to bring up the effect a little... there's no 'full harmonic mode' in that demo, just 'mixed mode'. The full harmonic mode is really pretty weak - I need to do some more testing to make sure I've not messed something up in the circuit. The mixed mode is more obvious with distortion, and it may need to be tweaked before its just right... a single resistor swap changes the transition point between normal and harmonic... I am really looking forward to seeing how you did the layout and how easily it will be able to fit into a standard guitar cavity... It will be tricky unless theres plenty of space... it takes up slightly less space than my old circuit install, so you can get a rough idea from that (until I post some images ) I have a similar problem. I find that some of my clean settings on my AX1G really bring out the fizz...I have found it happens with a straight amp too, so it isn't just the digital stuff...a clean setting with chorus really seems to bring out an ugly distortion squark fopr some reason, it does sound like the thing is overloaded or is processing sounds just too high for it to handle...not at all a natural distortion...hmmm Not sure that we're talking about the same thing. I'm talking about some fizz that is generated by the thing the guitar is plugged into 'loading' the guitar output (I think thats what is happening). Its not fizz thats there but quiet.. being magnified by an effect... the fizz really isn't there or is depending on the setting of the amp sim... I need to check that amp sim, I think its possibly faulty, or needs the input transistor re-biased or replaced. Brilliant...this is exactly the control I am looking for in my next install...can't wait to see how it all wired up and if I can fit it in the guitar sucessfully. However...I don't think that you would be able to get the bypassing of other pickups happening with a multi-pickup guitar like mine with the rotary control...any poles left in it? Perhaps it needs an on switch (maybe push/pull) plus the rotary in this kind of situation...if a suitable switch could be found... You can get some really chunky stacked rotary switches, it just depends on how much space there is in the cavity. The one I have used is a 3 pole 4 way, but you can get many more poles with a stacked switch, and even buy components to build your own custom switch. Very mild if you ask me and could easily be edited out or masked by other sounds in recording situations. I think that sounds acceptable. Sometimes mind isn't too bad, but I wouldn't want to switch it live as it could create a sizable thump! This is an option and I suspect how the commercial units get around it...at least in part. (I did notice the sustainiac patent had a floating ground, don't know if that would help...) Yep, I think the click I'm getting is just the electrical interference caused by the spark thats generated at the contacts when the power is connected. The best approach (for an SMD miniaturised board) would probably be some fancy chip that has very low standby current, and can (with some additional circuitry?) control the power supply to the rest of the circuit, turning it on and off slowly - e.g. in a few milliseconds. This lag wouldn't be noticable to the user, but may be enough to prevent any obvious pops or clicks. All sounds a bit vague, but there are solutions out there, I just haven't done enough research because my board is already too big )

Yet another new demo from me - this time no distortion ! sustainer clean demo starts with no sustainer, then normal, then mixed mode. cheers Col

Some good news to cheer Pete up I finally got my install debugged and working. Uploaded a new demo to soundclick sustainer clean demo starts with no sustainer, then normal, then mixed mode. I find that full harmonic mode is not so useful with a clean sound - maybe because of the dual rail, dunno. Anyhow, excuse the quality of playing and production, just listen to what the sustainer adds compared to the non sustainer sound. I have a pretty good stripboard layout for this circuit, but I need to edit it to point out where the connections are for input, output, power, switches etc. At one point, I thought that the fizz was back.. aaarrrggghhh Hoever, I discovered that it was being caused by my Amp sim being overloaded and in turn loading the unbuffered pickup signal... looks like I will have to be careful about what I plug into... no change there then... Right now, the pots are all internal, and I have a 4 way rotary switch on the face of the guitar - positions are off/normal/mixed/full harmonic. This seems good, but I may stick a pot on the front if there is enough variation in effect throughout the life of the battery. The switch on click is very quiet, but bad enough to be unacceptable in a recording. I don't think there is a way around this other than having the circuit powered all the time and just switching the poweramp on/off, or disconnecting the input.... Then minimum drain will be about 11-13mA. I'll have to wait and see if I end up using the non-sustained sound much... if the novelty doesn't wear off, then maybe I'll try that approach out... Thats all for now Col

from the reviews I've read, Kinmans are miles ahead of the pack. If someone were to attempt a stacked driver, it would make sense to follow Kinmans ideas and build two completely different coils - one designed to drive the string, the other to restrain the magnetic field while producing as little drive as possible - minimizing cancellation. Getting the balance right would take a fair ammount of experimentation, but could potentially provide a good result... I'm not even sure if having the coils close together on a rail driver would be the best option. It would be more compact, and alow us to keep more distance between the driver and pickup, but it may turn out that a decent gap between the coils allows more of the flux circuit to cross the region of the strings - a very compact rail driver might be too good at restricting the field - difficult to say without more experimental results. Really sorry to hear how bad things are right now, I hope you start getting it all sorted out soon. Good luck. Col

Surely its the direction of the magnetisation that is important - the polarization.... and that is the same throughout the magnet, therefor the cores of both coils have the same polarity. My understanding is that the overwinding is to compensate for losses due to cancellation - ie humbucking of the guitar string signal. EDIT: From Wikipedia (I know, I know, not the most reliable source) "Instead of two coils arranged beside each other with both coils producing string signal as in a regular humbucker, stacked coils are arranged one on top of the other with the objective that only the upper one should produce string signal. However the desire to stop the lower coil producing string signal was never completely achieved, most pickup designers did not fully address the effect of magnetic coupling and mutual inductance interaction between the two coils. Consequently both coils picked up string signal and signal cancellation occurred between the two coils along with cancellation of hum signals. The pickup tone was once again changed and different from either humbucker or single-coil pickup. Stacked humbuckers have a higher than average pickup DC resistance as a consequence of overwinding the coils with extremely thin wire. This overwinding is done to raise the output to an acceptable level, but will cause the higher frequencies to be attenuated due to the increased impedence." Col

The problem with the stack is the way it works. Pickup wise, the core polarities are not opposite, they are the same - the reverse current flow in the two coils makrs the overall polarities opposite - the only reason it doesn't cancel all the sound is because one of the coils is much further away from the string than the other... remember that the strength of the feild changes with the 'inverse square of the distance', so if the lower coil is twice as far away from the string, the upper coil will collect 4 times as much signal from the string.... in other words 25% will be lost through cancellation.... fortunately in a real pickup, the near coil is probably closer than half the distance of the far coil from the string, so the losses are smaller. What if we use this as a driver... hmm the two coils are fighting each other, does this mean that the magnetic flux generated by the lower coil is kept away from the string and has little or no effect... therefor wasting about half of our input power ? Or is it just the reverse of the pickup causing us to lose something like 20% of our drive ? Not sure, but either way is not good Col

Both the mail order places I checked had the TDA7052A in stock in a dip package at a reasonable price ~ £1.20 Yep, that seems to be the case, however we still donh't know how much of the fizz is due to electrical noise from the driver circuit, and how much is from crosstalk between the magnetic fields of the driver and pickup. It is likely that my current circuit _seems_ fizz free because the waveform of the crosstalk and noise closely matches that of the through signal, therefor it is masked. If I move the driver gets moved closer to the pickup, fizz returns - suggesting that at least some fizz is due to transformer action between driver and pickup, and that when you get closer than a certain distance, the voltage gained via the transformer action is enough to cause clipping. My earlier circuit also allowed the system to run very efficiently, only providing just enough drive to keep the sustain going - unfortunately it had plenty of fizz ! I think that this is not because of the level of the signal but because the signal was being distorted - not hard clipping, but asymetrical soft clipping... So the real trick is to ensure that the waveform of the driver signal matches the guitar signal in all but amplitude - I would guess that even phase changes will give some level of woolyness to the sound - although in harmonic mode, this should only occur until the note has morphed to the harmonic... It seems that Pete has already done a lot of work in this area, I'm not sure how big a return we would get from doing much more, unless you have a radically different idea about construction or functionality. Maybe using laminated core materials or custom magnetic cores would help, but then it's getting further away from being an accessible diy project... or going to a hex pickup/driver setup so drive is only applied to strings that are undamped... or building a hexaphonic gravity drive from nanotechnology components - beam those strings up Scotty FWIW, I'm half way through building an installation circuit for my latest setup, if that gives the same percieved quality as the breadboarded version, I'll be happy with the functionality. The main reason for me to go on with development would be improving efficiency in order to reduce the battery drain. I reckon that the best way to make a noticable and repeatable improvement in that area is to switch over to class-d power amplification. I'm not concerned at this stage with a middle position driver - there's no middle position on my guitar.... it would be nice to have two driver/pickup combos.. so I could have bridge pickup with neck driver or neck pickup with bridge driver, but right now I would be happy with just a bridge pickup and a neck driver with reasonable battery life and no fizz. cheers Col

Just a quickie, I bought a TDA7052 chip yesterday - its a BTL chip, but not class-d AFAICT. Seems like a possible good replacement for the LM386. The most interesting thing is that while searching for a datasheet, I discovered one for a TDA7052A This looks extremely promising - it's the same as the TDA7052, but with the addition of voltage controlled gain. If this chip is easily available, it could let us have the same or similar AGC functionality in a much simpler and smaller circuit.

Sounds like your mode 1 is harmoinic mode. Also sounds like the frequency response rolls off at too high a frequency - that would explain why the harmonic mode is loud while the fundamental is almost not there... What happens when you increase the gain ? It might be that to get fundamental going, you need a gain setting that pushes the harmonic mode into oscillation... Did you super double, tripple check your circuit for dry/unsoldered joins, wiring errors, caps the way round, layout design errors etc. ? You may need to change output cap (and possibly input) to larger values... Another possible cause is the driver - are you using the suggested wire guage ? What about core material and dimentions? What is the resistance reading for the coil? G is the most 'lively' string on my setup as well - you have to damp it if you want others to ring... AGC helps in many ways, but it doesn't stop the G string overwhelming the others when you don't use damping techniques. things that can help are - adjust the pole pieces of your pickup, use different string guages, build a driver core with a staggered core (vary height, thickness or both), fit a partial shield plate to limit the magnetic pull on the G string - one of the plethora of patent pictures Pete posted (don't try to say that while drunk) shows this idea. Col

Tried it, no dice. Even with only the bridge pickup and driver in the circuit, it oscillates with every pickup I have. I wound a new driver tonight, so I'll try that out tomorrow. Is your driver single coil, or dual rail ? I've been using a dual rail for all recent tests as it produces far fewer EMI problems (including being much less sensitive to sqealing feedback) Col

The truth comes out at last just kidding - I think you've mentioned it before, but until now, I didn't really think about it in this way - maybe your stacked bridge pickup is why your results with the basic system have been so much better than everyone elses ! e.g. no major fizz problems in normal mode Well...I am not too sure about this. Just to be clear, the driver is built on a very ordinary single coil pickup in the neck, the mid is identical without a driver and the bridge a stacked pickup...(cost about A$30 new....) This guitar was sacrificed to all kinds of experiments. One idea I had was that if it would work on such a cheap POS single coil guitar, it would work on anything...a lot of testing was done with this and another guitar when it had single coil pickups only in it... I know, what I'm talking about is that the pickup you are using to feed the sustainer is a stacked humbucker - this may be significant (in fact a cheap one may be better than a kinman with its asymetrical coil setup) I and I believe Curtis (?) and Tim have had issues with fairly obvious fizz... the fizz I've had will not go away with the tone control ! I was surprised when you said that it was less of a problem on your setup and that it was only really noticable in harmonic mode, but being reminded that you use a stacked humbucking pickup rather than a normal single coil suggested to me that this may be a partial explanation. Did you change from using a normal single coil pickup to using a stacked humbucker at some point? if so, did you notice (for whatever reason) a reduction in fizz at around the same time? As far as leads, have you tried making one of those inter-8 weave cables I posted about - its really not difficult to do, and they seem to work - I'm using a driver cable nearly a meter long that goes from an open breadboard (nest of wires) into the back of my guitar right past the pickup and its cables.... seems to be very little EMI from it. ..... I'll try to explain my idea about why a stacked humbucker could be better than a traditional side-by-side one using some simplified (and quite possible wrong) maths: my understanding (is this correct?) is that the energy of the magnetic radiation falls off as the inverse-square of distance... so lets say that the energy at the driver is 1000 units - doesn't matter what they are, distance from driver to inside coil = 9.5 cm distance from driver to outside coil = 10.5 cm the energy at the inside pickup coil will be 1000x(1 / (9.5x9.5)) = 11.08 units while at the outside coil it will be 9.07 units That is quite a big dicrepency - after the humbucking cancellation has taken place roughly a fifth of the magnetic radiation from the driver will still be in there.... if the coils are stacked instead of side by side, they have the same distance from the driver, therefor the cancellation will be much more efficient If we look at a mid position driver from the same POV: distance to inside coil is 4.5 distance to outer coil is 5.5 again assuming the same imaginary 1000 units from the driver, energy at the inside coil of a standard humbucker is 49.4 energy at outside coil is 33.06 So this time it even worse !! there's roughly 4 times as much radiation and in a horrific double whammy situation, _two_ fifths of the EMI from the driver will fail to be cancelled by a normal humbucker ! This may be a bunch of nonsense - needs verification by someone with more knowledge than me in this area, but it matches my experimental discoveries in terms of moving the driver closer to the pickup, and as I said, may help to explain why you had less trouble with fizz even using a similar specced driver and a functionally similar circuit... noting also that you have a heavily clipped driver signal and that that would create a huge fizz issue on my setup and on that of at least one other sustainiac here (can't remember his name) cheers Col

btw, did you breadboard it, or build it on strip or perf board? If its breadboarded, wait a while until you make a more permanent version, I have a much more effective 'mixed mode' approach now. The switchable input cap thing doesn't make a good mixed mode, it helps a little to encourage harmonic bloom, and at the same time reduced low end performance (as you would expect), but its not enough of a difference from fundamental mode to be worth wasting a switch on... What I'm doing now is based around an all-pass filter. This provides a phase shift that ranges form nearly 180º at 82 hz (low E) to almost 0º (360 really) at high e 12th fret.... in practical use, most notes up to about the 8th or 9th fret bloom quickly and easily to (mostly) octave harmonics.... higher up the fretboard, its back to fundamental mode. There is still reduced performance on the low E string, but I can live with that. Implementation wise, the idea is to share the op-amp used for full harmonic mode.... this means using a 2P3T toggle switch, a rotary switch, a combination of switches, or compromising and choosing one or the other of the two harmonic modes. Once I have this fully tested, I will post a scheme and then when its built and verified, the strip-board layout. Col

Good point, I also have a power supply cap thats not on the schem accross the battery. Try wiring up only the bridge pickup and the driver - disconnect everything else. My guitar is a Riverhead Jupiter700 !! its a bolt on neck 25 1/2 scale with trem and two humbuckers. I removed the neck humbucker for sustainer development. The bridge pickup is a Duncan Jeff Beck - a very 'hot' pickup - the original Seymour Duncan IIRC. My sentiments exactly The sustainer strat of mine does have a cheap stacked humbucker in the bridge position. The truth comes out at last just kidding - I think you've mentioned it before, but until now, I didn't really think about it in this way - maybe your stacked bridge pickup is why your results with the basic system have been so much better than everyone elses ! e.g. no major fizz problems in normal mode This is a good result...I take it that the driver was above the strings, so the effect would be better if it were properly mounted. If the device could be made smaller with Tim's coils or something...could be on to something. No, it was under the strings, I just managed to squeeze it in there - couldn't play high on the neck, but there was just enough room for testing. The rail driver is definately an improvement over the single coil You're probably right about the high frequency thing... oops, gotta run Col

So, I decided to see how things are like in the middle position with my latest setup. Verdict: Good and Bad Good - with the driver bang in what would be the middle position in my guitar, no squeal - not even a hint. Bad - Harmonic mode squeals like a Pig having an orgasm Bad - In normal mode the fizz is back Good - the fizz in middle position is not much worse than it was in neck position with my old circuit. Question: With a stacked humbucker (or a normal one with inside coil attenuated), would the fizz be reduced even more - perhaps enough to make middle position a realistic option ? VERY GOOD After this experiment, I got paranoid that my initial statement that my new circuit has dramatically reduced the fizz may have been wishful thinking, and that what I had believed to be clipping from my amp sim was actually fizz from the sustainer. So I dragged my old Pignose out of the pile of Junk it was festering in and plugged the guitar straight into it.... clean tone, no clipping, no distortion, mucho sustaining, NO FIZZ !! probably if you plugged into an ultra clean amp with very good headphones or monitors, you would notice some quiet fizz or at least woolyness, but through a normal guitar quality amp, it seems clean to me Col

It's possible. Downsides: noise - you lose the noise cancellation in the signal to driver, so I would imagine that the system will become more sensitive to EMI. You don't cancel much fizz - You may remove a little fizz, but if you are using the full humbucker for the output, the full humbucker will detect and output EMI from the driver - I reckon that until you get near to the point of squeal, most of the fizz is this 'primary fizz' as opposed to 'feedback fizz' It may help to reduce sensitivity to the squealing feedback that occurs as the EMI gets stronger, this is where the signal back to the driver becomes more important. However this effect may be nullified by the downside of not having humbucking for the driver signal. And the larger passive magnetic circuit of the humbucker may also lessen any possible advantage. So, it may be slightly better or worse(would be my guess) as far as sensitivity to squeal, but no discernable change in fizz levels. Now we need someone to try it out and prove me wrong - or right. EDIT: Something that might be worth trying if someone does experiment with this approach is to stick a volume pot on the inner coil. It's likely that the inner coil picks up more magnetic radiation from the driver than the outer coil (bridge side), reducing the output from the inner one to the point where the signal level of the EMI is the same from both will improve the humbuckers cancellation ability - so it will become less good at cancelling 'normal' electrical noise, but better at cancelling the localised magnetic radiation from the driver. Of course, if this requires a big adjustment to be effective, then it won't be so useful - we don't want to bring back electrical noise, and lose the tone of the humbucker... but if it only required a small adjustment, it could be a good approach for a permanent installation on a 'sustainer guitar'. Thats assuming it works AT ALL - but IF it does, it may be another step towards realising a middle position driver (with bridge and neck humbuckers). So... has anyone tried a sustainer using a stacked humbucking pickup in the bridge position and compared that with a traditional humbucker ? I wonder if that might be the best type of pickup to use.... a strat with Kinmans in the bridge and neck and a sustainer in the middle ? !!!! hmmmm... Col

Unfortunately, it is going to be rather large unless there is at least a pcb for it - preferably with SMD parts. Right now I'm working on a stripboard layout for everything but the LM386 section. It uses 3 dual op-amps and at this stage is 26 x 18 holes of board. It's fairly well optimised, so I doubt it could get a lot smaller without at least going to 1 quad + 1 dual amp - even then, it's going to be quite large. No problem for me - but not easy if your axe has a small cavity. If we do get to the SMD stage, it would make sense to use some switching chips to alow for simpler smaller hardware... otherwise everyone will have to decide where the best compromise for them is... depending on the space they have and their setup, some might opt for no harmonic mode malarky, others may have to stick with the basic fetzer/ruby. looks nice - mind you, if I was buying a strat, I'd want 3 single coils.... I guess you need a humbucker though What I really want is a 3 single coil guitar with 24'' scale - maybe a mutant mustang type of thing. I like the Brian May sound, and he used a 24'' scale. I don't have big hands, and the smaller scale would make many licks and scale shapes more accessible. And of course, in addition to that, you can imagine that a sustainer would work much better with the lower string tension that 24'' scale provides. cheers Col