# Sustainer Ideas

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True...

- a magnet had a North and a South pole

- the magnetic field runs from one pole to the other, they do not go in both directions

And also, (remembering of course that magnetic field lines are a simple graphical constuct of a field)

- lines of magnetic fields can't cross

- the closer the lines the stronger the field

- the lines are conventionally drawn flowing from north to south, could be either way they are not actually moving as such, it is a way of imagining the energy flow

- lines will tend to favour ferromagnetic mediums (such as steel, etc) over free space to the extent that that material can hold that flow (saturation, etc)

- a changing magnetic field (electromagnetism) is effected by the "permeability" (kind of magnetic memory) of a material...the extent to which it will give up it's magnetism and reverse the magnetic flow...

However...those drawings are right...

In the single coil like a fender, the magnet extends right through the coil so one end is north and the other south.

It is often beneficial to think of magnets as degree's of north and south. What is the magnitism in the dead centre, between the two poles? If the energy is really flowing as the line representation suggests, what is the flow at this point? Between two like poles, the fields are being repelled and forcing the magnets apart...yet, if you were to stand between the two fields ith a metal rod in the dead centre, you would feel no force, so is that a neutral zone despite the pressure?

Similar things happen when you consider the vibrations of strings. We draw them as moving up and down in waves. Then we combine the fundumental (the biggest wave) with various levels of (shorter) harmonic waves. But in reality they move in 3D and the waves are vibration in a complex way influenced by the instrument and the ability of the pickups to be sensitive to the detail of that movement. This produces the "tone" of the guitar.

For instance, with my hex designs, they evolved into a system where two magnets created a field on either side of a string, perpendicular to it. An electromagnetic element moved in another direction and the string in another...the result was a balance. When a signal was applied to this balanced system, the fields forces came into play and the string was dragged with the changes in forces...

But that was very complex and with a system like that alignment is crucial. Hence I aimed for that device to run near the bridge. It does work but not entirely practical. It was fairly self contained (low EMI and EMI in a contrary flow to the pickups) but not enough to run that close to a pickup. In part I was hoping to capitalize on the huge metal magnetic "sink" of the bridge itself to protect them, but alas not enough!!!

Anyway, that little story was to demonstrate that very complex and novel arrangements can be made with magnetic flows once you combine multiple magnetic fields in balance.

The simple driver is much the same (as is a pickup in truth)...the flow of the magnetic field changes with the drive signal (electricity in the coil). As it flows one way the north pole becomes more north and the south less and visa-versa. Then, it quickly changes as the signal flow reverses. The ability of the core or magnet to effect such changes (the permeability and saturation, etc) are by far the most important considerations.

What we are doing is manipulating the magnetic field/s. The field it self is secondary...the flow is only there to be manipulated. So, there is a lot of VoodDoo about magnets. Is Alnico better than ceramic? Well, only in the strength, size, permeability, etc of the material of the stuff and the field it creates...the field is the same, no matter the material that the magnet is made of.

So, I don't like people to get too hung up on the magnet issue. Even less important than with pickups, it is the effect of the coil to effect change, that is vital. Hence of equal or more importance is the electromagnet...the coil. How many turns, the guage of the wire, how much energy can be driven down that wire, coil resonance, how fast can the coil accomodate changes in signal direction...all very important issues.

In fact, the whole thing can be, and is, extremely complex... Yet so simple! To get the thing to work, through trial and error we do have a recepie of wire guage, coil shape and resistance to drive strength.

There are so many ways to create the effect, but it is the effect that we are after...is one way better than another...possibly...but if one simply wants to create the effect...infinite sustaine of a guitar string...well, we can do that...

Frankly, I did the brain strain to save others from having to! Many people have tried to do this in the past with various degrees of success and failure. We have seen time and time again that in changing some crucial elements (say wire guage) beyond our broad tolerances and the thing work unsatisfactorly. I'm not suggesting that my way is the only way, that there can't be improvements, that we shouldn't strive for more (all pickup selections, a bridge driver, etc)...but I am not at all sure that the theory, especially of the static magnetic fields will produce results. At best these ideas can be a source of direction for exploration, you really need to make them to see how they go...untill they are a reality, you wont really know how they will react. Yes, I did make working complex drive systems using these ideas but it took me down a road far from the prime goal because I wanted more. Sometimes enough is enough and the simple is the best approach...just something to consider... pete

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Hello again...just looking in after moving to my island...getting a bit chilly down here! Good to see the thread continues the tradition of long threads! Still...the computer didn't survive the mov

Excellent... This will be great, and I hadn't thought about that but the 4 ohm coils would take half the time and be easier to wind....alowing the use of quick epoxy like this...hope you wore rubbe

OK...back to reality...

Once some more guys get these things working we could exchange Sustainer Techniques and what such a device can do!

Here's somethings interesting...

If you play a note as a "artificial" harmonic an octave (12 frets) above the note...it will continue to sustain at that pitch (an octave above)...

If you slide or pull off that harmonic to another on the same string...it too will sound as an octave even though you didn't use the AH technique...cool!!

Seems that pinched harmonics (pick harmonics) morph back to the sustained pitch (drops an octave during the decay of a note).

Also...low notes in fundumental mode (i.e. towards the nut) tend to morph into consistant octaves above the fundumental...so the low E will morph into the E at the twelth fret an octave above.

An artificial harmonic not an octave above (say a fifth or fourth) will morph back to the fundumental...then morph into a higher harmonic if a low fretted note...

Higher notes tend to sustain at there actual pitch...an artificial Harmonic (well above the fret board) will morph back to the fundumental on high fretted notes (abover the 12th fret...

In harmonic mode...notes will feedback and quickly morph to a higher harmonic pitch an octave or much more above the note. This note will be a part of the harmonic series. They can be different for the same note depending on the length of the string so even with the same pitch you can get different effects depending on where you fret it. The harmonics are predictable and consistant and always sound kind of musical because they are pitches from the natural harmonic series of the vibration of the string (not the compensated fretted pitches)

On my guitar, notes fretted higher on the board seem to work better because by pushing down on the string, the string is pushed physically closer to the driver...even though these very high notes have been cited as difficult on older commercial systems...

My circuitry uses a 100uF output Cap to the driver from the LM386. This reduces the bass response. The other circuits I have made have used different sizes and 100uF is not typical...this may explain this octave effect on the lower strings...so...you could add another to get a true fundumental or maybe have them switchable with the mode to get different responses...something to consider

I am still looking into my guitars circuitry...the thing kind of evolved so there is no set circuit...they all worked but this one is working really well so I thought I'd better have a closer look if I am to make replicas!!

I'd love for you guys to be able to play the thing and explore the possibilities...got to make one first...tempted?

pete

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damn you psw for being so damn smart and building this thing! if i knew what the hell you gyus were talking about half the time and if i had any idea how id definately make one. i havent read all 79 pages, iv skipped and jumped through bits of it, but from what i have read of it, i think people would be climbing over their dead grandmother to get hold of one!

leds or no leds, internal or external controls, either way, any combination, people will want it. it will make for a very versatile instrument that could encourage new playing styles and more originality - and god knows thats jus what the music scene needs.

if/when you do bring it out commercialy, i think you should let everyone whos contributed to this forum have one at cost price hehe

seriously though, what a fantastic amazing thing you've done

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Welcome and thankyou hooglebug. A welcome to starry_night who emailed me this...

i really do understand how to create your version of diy sustainer (the fetzer-ruby) but what bugs me is the BASIC FLOWCHART LOGIC of sending the freakin signals and i cant get it where to put what... i mean, ok we start at the bridge pickup as our input, go through the circuit, then to the driver. now the question is, where do i connect the driver to? i mean in basic english please... because wherever site i go i always find the same schematic diagram without telling where to go next... so my first question is, from the driver, where does it go next? second, where do i get the signal to send to the guitar output? shall i get the signal directly from the driver? or shall i "reconnect" the bridge pickup on its own to the guitar output? i mean shall i send the bridge pickup rawly in two seperate ways? first to the circuit then the other one to the basic output? please sir i desperately need this... thanks in advance...

p.s.

can you as well umm.. tell me, where did you get the 'blade' that you used as the core? what exact material is the source of your core?

keep rockin...

Ok...here is a flowchart of the most basic connection...

This assumes one bridge pickup and one driver. The phase switch simply reverses the wires to the driver to produce the normal and harmonic modes of working. I have put in a bypass switch but in a single pickup guitar that would not be necessary, it's purpose is to select the bridge only and disconnect any other pickups.

This bypass switch may be required to do several functions and can get a little complicated. Power on/off, pickup bypass and bridge pickup only selection.

The driver operates like a speaker and connects to the speaker out of the sustain circuit (which is simply a small amplifier). A speaker moves it's paper cone whereas a driver moves the strings. It is built like a pickup but with thicker wire (to carry current) around a core which is magnetised.

The driver sits very close under the strings and is connected to them by the magnetic field. The strings are steel so the magnet in the driver also magnetises the strings as well. When a signal (an alternating backwards and forwards flow of electricity) goes through the driver's coil it creates a electromagnetic force. This changes the state of the drivers core from north to south in time (phase) with the vibration of the string (as picked up by the pickup operating on the same principle in reverse). So the strings, caught in the drivers magnetic field (which is changing) with the signal will be puched and pulled by it causing it to continue to vibrate.

(So the answer is, it is the end of the signal chian, like a speaker, but the magnetc energy connects it to the strings.)

This creates a "feedback loop". A vibration is "picked up" which is amplified and causes the string to vibrate, which is picked up, and around it goes. Each time around it will get louder and louder...to the point that the string can not physically move any harder (usually hitting the frets!!). The guitar will play itself if left on.

The harmonic effect is interesting. With the "phase" of the driver reversed (simply swapping over the wires) the driver will be doing the opposite. Instead of driving the strings, it will be trying to stop them!!! The effect is that it stops the vibration of the fundumental frequency (the main and lowest frequency of the note) at that point (where the driver is). This is just like plucking a string with a finger gently above the twelth fret. The fundumental will be suppressed, but all the other "harmonic" vibrations (behind the fundumental) will be heard. These vibrate at shorter, higher frequencies and will be driven and increase in volume through the feedback loop effect.

In my drivers the core is typically a "blade" made from ordinary 3mm mild steel as you would find in a hardware store with a magnet attached to the bottom. You could alternatively use the magnet as the core if you could find one the right shape. With my pickup driver the blade goes right through the driver, through the pickup and the pickups magnet attaches below and works for both the pickup and the driver.

The driver design is typically very thin (mine about 3mm deep) and is the unique aspect of this design. On a separate driver you will need to cut down the steel to this kind of thickness and make a suitable bobbin to hold the wire on. It is very important that the wire windings are potted (ie glued) to allow no vibration.

So I hope that helps clarify things and eases the desparation . The thing to note is that the bridge pickup connects to both the sustain circuit and to the output of the guitar. SO you hear the bridge pickup just as if the sustainer was not on, no signal to the guitars output and amplifier goes through the sustain circuit. The guitar's sound is unchanged except that the strings will now sustain forever. That means the tone of the guitar will be unchanged. It will work acoustically without being "plugged in" at all, clean or as distorted as you like.

nice to see some interest still... pete

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(So the answer is, it is the end of the signal chian, like a speaker, but the magnetc energy connects it to the strings.)

now this ends my case... very much thanks pete!!!!! youre a much great help!!! desperation ends here

Edited by starry_night
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You guys seem to be well on your way to a finished product, but I thought I'd share my experiment anyway. The first time I tried the sustainer thing was about 5 years ago. I rewound a vintage-style single coil with 100 or so turns of 32 gauge magnet wire. I wound the entire bobbin, not just the top portion. I didn't work very well at first, so I added some neodium magnets. This worked for the lower strings, but I still couldn't get the B and E strings to sustain. At this point other projects took priority and I basically shelved the sustainer until now. I never did any real testing on it because I didn't own any test equipment at the time.

A couple weeks ago, I bought a busted Lace Sensor from a fellow PG'er. I figured I could probably repair it, plus I was curious to see what it looked like inside. It turned out the coil was broken in several places and I decided to rewind it, but as I was looking at the pickup it hit me that this would be a great place to start for a second sustainer attempt. The Lace Sensor has a very short, narrow coil that is right at the top of the pickup. Its bobbin is steel and it helps to conduct and shape the magnetic field, which also appears (although I haven't bothered to model it) to be highly focused. So I wound the coil with around 180 turns of 31 gauge magnet wire (about 10 ohms). This time I used a transformer winder, so the coil is nice and tight. I didn't get it exactly square on the bobbin (one side is thicker at the top while the other is thicker at the bottom), but I'm thinking this might actually help my string-to-string balance. When I tried it out, I was able to sustain all the strings, though the E and B still take a bit more 'motivation' to get going.

Here are a few observations that I found interesting:

- My coil needs to be potted -- badly. I don't think potting is optional with these devices, as the coil vibrates enough for me to actually hear the notes through it sometimes. This can't be helping my efficiency. I've thought about wax potting, but I don't know if the wax will be able to wick into the coil well enough to stop it from moving. I think CA (super glue) would be quite effective for this, but it would be very permanent. I saw a mention of lacquer earlier, and that seems like a good compromise. I have some polyurethane around, so I think I'll try that first.

- The wave going to the driver in my setup is not even close to a sine. It looks more like periodic series of a delta functions with alternating polarity. This is not what I expected to see. I figured the sustainer would settle into a frequency it liked then sustain at basically one pure tone. I have a feeling this has something to do with the potting, as the coil has a resonant frequency that is a combination of both the electrical and mechanical parameters, and it will try to settle into that if I let it sustain for too long.

- I needed about 10V peak to peak to get the strings sustaining nicely. I hope that potting the driver will gain me a little in the way of efficiency, but it looks like I'm going to need all the voltage I can get from a 9V. I've seen some mention of the LM386 as a driver amp. It's a nice chip because it's cheap, simple, and fairly capable. It does not swing rail-to-rail, though. The typical peak-to-peak output at an 8V supply into an 8 Ohm load is around 5.5V. I plan to look at some circuits that can get closer to the supply voltage. A discrete implementation is probably all that is necessary, but I'd like to take a look at some of the newer MOSFET output opamps and line drivers that are around.

Anyway, I hope these observations are welcome. It may be a while as I have about 10 times more projects than free time, but I think I can improve on current amplifier and possibly even provide some PCB layouts.

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Good Stuff fookgub...and welcome to the sustainer thread!

I admire some of the ideas the Lace family have come up with from their many, many patents and I remember contacting them when Lace Snr. died a few years back. Many of their designs including the ones with Fender were quite focused thanks to diverting comb sheilds and i did muck about with them (and similar sheilds are featured in the renown hyped up Kinman stacked designs) and they are still making some innovative designs (like the Alumitones).

The Lace Sensor has a very short, narrow coil that is right at the top of the pickup. Its bobbin is steel and it helps to conduct and shape the magnetic field, which also appears (although I haven't bothered to model it) to be highly focused. So I wound the coil with around 180 turns of 31 gauge magnet wire (about 10 ohms).

It's interesting as with your second attempt you have done much like the model I proposed here with the thin driver model. A closely wound coil on a small bobbin, even the wire guage is similar if I'm not mistaken. An ohmage of 8 or less would make it more efficient and faster with your typical amp like a LM386.

- My coil needs to be potted -- badly. I don't think potting is optional with these devices, as the coil vibrates enough for me to actually hear the notes through it sometimes.

You are very right about this...potting very necessary. I used PVA on mine and propose that as a safe medium to actually wind and pot at once. I don't think even soaking the coil is as good. Lacquer is probably better. I wouldn't use super glue. You are bound to get vibration and this may remove the enameled insulation in on the wire and cause shorts as it breaks (it is very brittle) plus it is a little dangerous and will stick your fingers to the coil. Tim made a fantastic one without a bobbin at all set in epoxy and this is probably the ultimate potting for this...again the epoxy was done while winding, not post-winding. You are right, the loose windings will cause their own signals/resonant frequencies that will effect efficiency and even it's ability to work properly. Also, these windings will cause signals that will create noise if they get into the pickups.

- The wave going to the driver in my setup is not even close to a sine. It looks more like periodic series of a delta functions with alternating polarity. This is not what I expected to see.

Hmmm...I'm not sure what a delta wave function is...lol...but you shouldn't expect a sine wave as that is not what the guitars signal is anyway. My preamp has so much gain it is probably closer to a fuzz like square wave...the inheirent compression this causes is also beneficial.

- I needed about 10V peak to peak to get the strings sustaining nicely. I hope that potting the driver will gain me a little in the way of efficiency, but it looks like I'm going to need all the voltage I can get from a 9V.

Well...mine uses a LM386 on a single 9 volt and lasts a few days. I realize I am not getting the full power, but I really don't need anything like 10 volts to run this thing. The LM386 is all those things you mention plus is pretty power conservative, simple, cheap and easily obtainable. I have looked at various alternatives with D-class switchmode amps being of particular interest. They tend however to be hard to get, expensive, and only in SMD so not really suitable for DIY anyway. I am sure there are many alternatives.

It sounds like you know a bit more about the electronics practicalities and options. I am looking at doing some kind of standardized circuit especially for this, but found that even experts seem to have a little trouble with the concept...perhaps it is too simple!!! You might be a candidate to help develop the circuit further.

For everyone reading this...I do not use the Fetzer/Ruby circuit. This was proposed by Galaga_Mike in his tutorial and is a worthy option. In comparison, my preamp has some filtering and many times the gain of the fetzer. I have not even made that circuit, but that will be my next step I think to see if all the gain I have is so necessary. I have tried less, but this is better and I put it down largely to the natural compression created. Someone suggested I'd need at least 3 fetzers running into one another to get the same effect.

Anyway...I am convinced that the key to this "project" is the driver design and the method of making it as you say. A thin condensed coil with a narrow focus, 0.2mm (or thereabouts) wire, very well potted is the recipie that seems to work best. Variations will work, but to lesser degrees. The amplifier circuitry is not the key to a successful sustainer with this project as I currently envisage it, thought there is some work that can be done there.

Typically the higher strings have been difficult to drive. Sustainiac and Fernandes have gone to great lengths to address this problem in the past. Mine actually seems to drive best on the g and b strings although a good response is obtained on all strings over the entire fretboard. The fact that different qualities and responses can be obtained from different strings can be used to musical advantage too. If high string response is a problem I would have a slightly lesser number of turns (ohms) and reduce the output capacitor from the LM386 to lessen bass response (driving the bass strings is not a problem). You may find that driving the harmonics more problematic than the fundumental.

If you are looking into circuit designs, remember that most people will not want to put more than a single 9volt in the gutar to run it (even if there is room) and want it to last a fair while (although this will always be relatively short compared to a typical stomp box). More power will certainly help...but...you will be putting out more EMI and need to have more power available on board, and be churning through it.

As far as what I have been doing regarding the circuit...I have had a really good look at mine and found things I didn't realize I had done to it (it kind of evolved) and passed it on to someone else who did a scratch layout...this board is 3.5"x0.8" but I'd still like to see it smaller. It does feature some really cool options though. I have made it so you can have a sensitivity control as an option, none or an internal trim pot if you want, an LED out option plus in out and power. The switches are off board and so it can be adapted to any kind of guitar with hardware of your choice.

But, as my domestic situation is still difficult to say the least, I can't really do any practical work on it to get it off the ground for a while so don't hold your breath and turn blue! I do think a standardized circuit would take away a lot of the angst about doing this project and getting more people sustaining away with it...and that is the ultimate aim... pete

BTW there have been quite a few recent posts about sustainers. Comparing the two (not that I've seen them) I think the Sustainiac may have the edge as far as flexability. Fernandes has the advantage of high profile endorsees (Vai, Edge, et al) and is the only way you can by one factory fitted into a guitar. As far as I know our DIY model is the only other proven alternative and has probably the most flexability. It is quite different in many respects but they all work on the same principle and should perform equally all things considered. I notice that we have suddenly passed 39,300 visits so there is obviously a lot of interest still in this project and the subject of sustainers in general. I think all those who have contributed to this extremely long running thread should be proud of it's standing. Thanks to all and welcome to all those silent viewers, as always, feel free to join in...there's way to much now to really take in if you tried to read the whole thread...it's likely to confuse you even more...perhaps we should have a best of the sustainer thread

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I just had an idea... Would it be possible to make the driver a pickup, plain and simply by running it's output to the preamp you alredy have for the sustainer. Maybe it would sound good, who knows?

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Good Stuff fookgub...and welcome to the sustainer thread!

Thanks!

It's interesting as with your second attempt you have done much like the model I proposed here with the thin driver model. A closely wound coil on a small bobbin, even the wire guage is similar if I'm not mistaken. An ohmage of 8 or less would make it more efficient and faster with your typical amp like a LM386.

True, but increasing the number of turns will also increase the force on the wire for a given current, or buy you the same amount of force for less current (and longer battery life). Part of the reason I used 31 ga. wire was so the I could get more turns at approximately the same DC resistance. Of course, more turns also means more inductance, so there are some trade-offs here. My understanding of electromagnetics is not what is should be, but I feel like there should be an optimal operating point that balances wire gauge, number of turns, and coil impedance. I think it will be in the neighborhood of 30-32 gauge wire and about 100 to 200 turns, but I'd like to work out the math at some point.

You are very right about this...potting very necessary. I used PVA on mine and propose that as a safe medium to actually wind and pot at once. I don't think even soaking the coil is as good. Lacquer is probably better. I wouldn't use super glue. You are bound to get vibration and this may remove the enameled insulation in on the wire and cause shorts as it breaks (it is very brittle) plus it is a little dangerous and will stick your fingers to the coil. Tim made a fantastic one without a bobbin at all set in epoxy and this is probably the ultimate potting for this...again the epoxy was done while winding, not post-winding. You are right, the loose windings will cause their own signals/resonant frequencies that will effect efficiency and even it's ability to work properly. Also, these windings will cause signals that will create noise if they get into the pickups.

Potting the coil while winding seems to be the best procedure. You've got some insightful comments about superglue, and I think you're right that it's not the best choice. Since I'm still in the development phase with my coil, I'd like to stay away from epoxy (though this is probably the best choice for potting while winding). For now I'd like to stick with something that is more reversible, so I think I'll give the poly a try. We've got a vacuum potting system here at work that I'll probably use when I'm ready to commit to a coil design.

Hmmm...I'm not sure what a delta wave function is...lol...but you shouldn't expect a sine wave as that is not what the guitars signal is anyway. My preamp has so much gain it is probably closer to a fuzz like square wave...the inherent compression this causes is also beneficial.

By delta function, I mean spikes or pulses. I'd like to see how this changes when I pot the coil. I have a feeling there is a lot of energy going into coil motion. This is especially true with more distorted waveforms, where I can here the signal from the coil as if it was a speaker. A little fuzz is probably good for this design. As you say, the compression probably help the string-to-string balance. The extra harmonic content probably helps 'kick start' the sustain process, too. I'd like to see if the harmonics the sustainer operates at for specific notes can be repeatably controlled by playing technique. This could have some very interesting uses.

For everyone reading this...I do not use the Fetzer/Ruby circuit. This was proposed by Galaga_Mike in his tutorial and is a worthy option. In comparison, my preamp has some filtering and many times the gain of the fetzer. I have not even made that circuit, but that will be my next step I think to see if all the gain I have is so necessary. I have tried less, but this is better and I put it down largely to the natural compression created. Someone suggested I'd need at least 3 fetzers running into one another to get the same effect.

Is this the circuit you're referring to?

It seems ok for a start, but I agree that some filtering would help. The first time I did the sustainer thing, I believe I had a sharp low-pass at around 2k and overall rising gain from ~100Hz to the 2k cutoff. If I look around hard enough, I may even be able to find the circuit somewhere (unless I've already raided it for parts). The schematic was drawn on a napkin and is long gone (it took me a few years to figure out I should keep this type of stuff in a notebook). Anyway, filtering is something that everyone is going to need to adjust to suit their coil and setup, but I think there are some possibilities for improving the string-to-string balance here. The danger is that improving the high string response with more high frequency gain may affect the lower strings' ability to sustain at their fundamentals.

It would be interesting to be able to extract the fundamental (maybe with a zero-crossing detection scheme), and try using that as opposed to complex filtering. I haven't looked at it for a while, but I believe the Craig Anderton 'rocktave' circuit does something to this effect before dividing the signal down. Might be worth a look...

If you are looking into circuit designs, remember that most people will not want to put more than a single 9volt in the gutar to run it (even if there is room) and want it to last a fair while (although this will always be relatively short compared to a typical stomp box). More power will certainly help...but...you will be putting out more EMI and need to have more power available on board, and be churning through it.

Efficiency is king here. I'll be routing for a battery box anyway, so I'd rather use 18V, more for battery life than the extra headroom. I can see where people that won't be modifying their axes will want something that runs on a single 9V. Because this is a power circuit, battery life is always going to be at a premium. Hence the draw of class-d operation, which should be able to operate up to about 90% efficiency. The LM386 is probably more in the neighborhood of 50%. That sort of efficiency increase would be a big plus. As I recall, the Sustainiac patent specifies a class d amp, but I have no idea if they actually implemented it. A class d amp will also swing rail-to-rail, making better use of the available voltage.

Most of the choices for integrated class d are going to be surface mount, but that need not scare people away. MIMF has a piezo/magnetic preamp using SMT parts that many people with no electronics background have sucessfully built. Obviously high pin count and smaller SMT form factors are out, but there may be a suitable chip out there somewhere. We would need to find something that works with a minimal amount of outboard components and uses a readily available IC. The LM4673 looks to have a lot going for it, though the available packages are not hobbiest friendly. Also of interest are some of the newer microcontrollers with built-in a/d. One of these could be used to drive an outboard h-bridge, creating a simple open-loop class d amp. It would be a neat project, but probably not practical in the end.

Anyway, at this point I'm more interested in the coil than the amplifier. As you say, the driver is the key to this project. Once I have the driver settled out, and as time allows, I'd like to work on the amplifier and see what I can come up with.

Edited by fookgub
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Well...you really seem to have a handle on a lot of these concepts and your electronics knowledge outstrips me. A lot of my knowledge has come from practical trial and error and study specific to this project...so...

...increasing the number of turns will also increase the force on the wire for a given current, or buy you the same amount of force for less current (and longer battery life).
However...there are more things to consider than that. Resonance for one. But on most concern is the speed at which the coil can react to a changing frequency. This is where my design comes in. Commercial systems have gone to a lot of trouble to correct for phase shifts and physical focus on the higher strings.

My understanding of electromagnetics is not what is should be, but I feel like there should be an optimal operating point that balances wire gauge, number of turns, and coil impedance. I think it will be in the neighborhood of 30-32 gauge wire and about 100 to 200 turns, but I'd like to work out the math at some point.
So...through much trial and error (perspiration over inspiration) I have arrived at that region you are describing...there are other and perhaps more important factors at work than battery efficiency. You are right, there is an optimal range of factors that also include the core material, magnetic field shape, signal strength and amplifier design, coil shape, wire overlap, resonant frequencies, drive signal character, etc... Possibly too much to quantify with math...but the result is already been published here as far as this formula goes based on numerous experiments...

Potting the coil while winding seems to be the best procedure. ...For now I'd like to stick with something that is more reversible, so I think I'll give the poly a try. We've got a vacuum potting system here at work that I'll probably use when I'm ready to commit to a coil design.

Wow...where do you work!! Yes, you need to dampen down the windings I found PVA to be adequate (woodworking stuff dries pretty hard and has a filling effect) but other stuff would be better. Winding in epoxy could have hazards but the outcome is a solid block like this one of Tim's...

The extra harmonic content probably helps 'kick start' the sustain process, too. I'd like to see if the harmonics the sustainer operates at for specific notes can be repeatably controlled by playing technique. This could have some very interesting uses.
Yes, there is a lot to discover with playing the thing and specific techniques to learn (string damping is crucial on a guitar that tries to play itself!). The beauty of this device is that it is controllable, and the harmonics repeatable and "musical". They will not always be an octave above because of the fixed driver but they are certainly repeatable and predictable. There are unusual effects, as described earlier such as sounded harmonics being driven back to their fundumental for instance. As I have said, it would be great to have a "player's corner" sustainer thread to share techniques and musical ideas on using this device....need a few more made to do that though!

Is this the circuit you're referring to?
Well...that is the Fetzer/Ruby circuit that most are using...but not the design I use! What are you using...is it LM386 based?

Anyway, filtering is something that everyone is going to need to adjust to suit their coil and setup, but I think there are some possibilities for improving the string-to-string balance here. The danger is that improving the high string response with more high frequency gain may affect the lower strings' ability to sustain at their fundamentals.
My preamp has filtering to kill frequencies outside the audio spectrum. This is in an attempt to stop high frequency oscillation and detrimental EMI effects. Loose windings will also produce these kinds of unwanted signals and is another reason, along with efficiency, for it to be potted well. This is true but you do have to reach a balance with these things. Lower strings/fequencies on my guitar do tend to slowly morph into a harmonic one octave above the fundumental but string to string balance is good and the effect very musical. I am sure this is how the comercial systems got their "mix" control happening (though apparently very inconsistant). The extra ferromagnetic mass and lower tension and spped of vibration of the lower strings make them much easier to drive so having a high string bias simply tends to even things out overall.

Efficiency is king here. I'll be routing for a battery box anyway, so I'd rather use 18V, more for battery life than the extra headroom.
Well yes...all fernandes sustems used to run off 18v and more power, or at least current, is always adventageous. This device will always be power hungry compared to a signal processor you are not simply modifying a signal by filters and such, but generating an amplified signal enough to physically move the string...that will take some force! My thinking at the moment is that remote power is the best solution...not more volts but a consistant and higher current power supply with no on board batteries. One reason is that the way the device reacts as the battery goes flat and less grunt is available means that a song or technique that works with a new battery will not work with an old one... There are so many advantages that it cant be ignored...no routing of the guitar should be possible on virtually any instrument and the cost of battery replacement alone would pay for it in very short order.

Hence the draw of class-d operation, which should be able to operate up to about 90% efficiency. The LM386 is probably more in the neighborhood of 50%. That sort of efficiency increase would be a big plus.
Yes, Sustainiac proposed the idea of d class amps but in truth these things are becoming commonplace in things like mobilephones and such. I can see other reasons too for their use that may become more apparent when you get to a full installation of the device (hint: it avoids a common ground at the output). But...circuit efficiency is one thing...the device still has to physically drive a string which will take power. SMD is not typically available in domestic stores, are harder to work with and expensive to buy in small quanties. That alone should rule them out for most. I am intending that the whole board eventually be made avalable as a very small SMD board and it surprises me that the other companies have not moved in this direction with all their resources...if only to save space!

If you resign yourself to needing a fair amount of power and going for remote power, amplifier efficiency becomes something of a mute point. I have also found that although d class is efficienct they are often not designed to give good constant output power....this is important for a device that is sending out a constant signal such as a long sustained note...I do have something in mind and will try it eventually.

Of more benefit, would be electronic switching. The switching and rewiring is actually quite complex. An electronic switching system could greatly simplify it and offer control with the tinyest little push button surface mounted switch or any kind of switch that you choose. Unfortunately while I can envisage it, it is way outside my comfort zone and the space would be a bit much...but with SMD there would be no problem and well worth looking into.

Anyway, at this point I'm more interested in the coil than the amplifier. As you say, the driver is the key to this project.
Absolutely, the driver is the key. It may seem very simple and it is, but the recepie is important for all the reasons you mention and more and I believe that after all this time, I have happened across the happy medium of driver design...well at least for the moment and made that available for all (mainly cause I can't afford a patent!).

Pr3Va1L

I just had an idea... Would it be possible to make the driver a pickup, plain and simply by running it's output to the preamp you alredy have for the sustainer. Maybe it would sound good, who knows?
Well, that is how both Fernandes and Sustainiac have done it on some models. The driver is such a low impedance device that the sound will be different and not as "good" as conventional pickups. They are designed to do different things. A better idea I feel is the combination design that I have which incorporates both a conventional pickup and the driver in one device...you get the best of both worlds and passive with the sustainer off and the perfect placement of the driver. My next driver will be a stacked alnico singlecoil sized humbucker with the driver on top...I got the whole thing planned...now if only I had a house, etc....

All good stuff and exciting...how about some pics, some circuit details and maybe even sound at some point. If anyone would like me to post examples of how different "effects" occur (such as this low string octave thing, reversed harmonics and auto swells) let me know...

good luck all...I know there are a few working away in the background of their own sustainer project... pete

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OK...so I mentioned a few questions lately have come up regarding the Fernandes Sustainer and on The Sustainiac in comparison. Some are actually fitting them so perhaps they will report on how they go. Anyway, before they sink into the distant past of questions I thought I'd link them to here...so here they are...

Today I found this stuff over at Unfretted.com the forum for fretless guitars on fitting the fernandes sustainer with plenty of pics...Unfretted Fernandes Sustainer Install and Review Link

Well worth checking out if you are interested in doing this and has opinion on what is entailed in fitting a fernandes system. Of particular interest is the size of the board and the effect of having the switches mounted to it. This is a prime advantage of the DIY version...small size and adaptable to the guitar. With the Fernandes this the routing is massive...the Sustainiac is a lot more adaptable.

pete

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OK...so I mentioned a few questions lately have come up regarding the Fernandes Sustainer and on The Sustainiac in comparison. Some are actually fitting them so perhaps they will report on how they go. Anyway, before they sink into the distant past of questions I thought I'd link them to here...so here they are...

Today I found this stuff over at Unfretted.com the forum for fretless guitars on fitting the fernandes sustainer with plenty of pics...Unfretted Fernandes Sustainer Install and Review Link

Well worth checking out if you are interested in doing this and has opinion on what is entailed in fitting a fernandes system. Of particular interest is the size of the board and the effect of having the switches mounted to it. This is a prime advantage of the DIY version...small size and adaptable to the guitar. With the Fernandes this the routing is massive...the Sustainiac is a lot more adaptable.

pete

wow, the fernandes system is big! I wonder what all that stuff does... 4 trimpots, two switches, and did you catch that big transformer? I've pulled smaller transformers out of wall warts! I'm guessing their coil is not as efficient if they need a transformer to (assumingly) step up the output voltage. They used pin headers for everything else, so why waste board space on those big switches?

Anyway, I'd be interested to see a schematic. Judging purely on appearance, it looks a bit 'antiquated'... you know, like it belongs on one of these.

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Well...don't laugh too hard...wasn't it you fookgub who started us down the road to circuit refinements again...

It would be interesting to be able to extract the fundamental (maybe with a zero-crossing detection scheme), and try using that as opposed to complex filtering....etc

I hadn't noticed that transformer before , no...hahaha. But, the way that fernandes has approached it does make sense.

wow, the fernandes system is big! I wonder what all that stuff does... 4 trimpots, two switches, and did you catch that big transformer? I've pulled smaller transformers out of wall warts! I'm guessing their coil is not as efficient if they need a transformer to (assumingly) step up the output voltage. They used pin headers for everything else, so why waste board space on those big switches?

OK...some of those trims no doubt controls gain, possibly pre-gain, maybe filtering and certainly the gain of the preamp for the driver when it is used as a pickup. You do need to have two switches and it can become a rats nest when not mounted on the board so having them on board does make sense and take up room. Any wiring left to the end user or even factory installations are just asking for trouble and extra expense. There are about 24 extra connections required to get those switches off-board....now there's trouble!!

The transformer could be a way to boost the driver enough to work as a pickup, or to allow a more pickup like driver to operate as both a pickup and a driver...or it could be something else...lol

Of course the drawback is the need to remove a significant amount of guitar, the restriction on the placement of switches and you will notice that you not only loose your choice of neck pickup for the driver but the single coil bridge pickup also needed to be replaced for their humbucker...hmmmm

Then there is the cost of installation....this kind of modification into a guitar of any worth is not for the faint hearted, a lot of techs wouldn't be up to such extensive routing (lucky here that the thing is hidden under the scratchplate...but the placement of the switches are of concern).

So one shouldn't be hard on them for trying to simplify installation...this is one of the most difficult part of the operation. You will notice that many have watched this thread, some have made the device but very, disappointingly few, have gone on to a fully realized install!!! While the thing is fascinating and getting those strings playing by themselves for the first time really is a thrill (it's like magic, really), it is not untill you have a proper working instrument happening that you get the thing to work properly and can really appreciate it's potential. Prototyping is one thing, but untill it is properly installed it will not work quite right.

But you are right....the fernandes and sustainiac to a slightly lesser extent, have designed their "product" to assume the least skill by the installer and still suggest professional assistance (for good reason) and offer no aftermarket support (it really would be too hard to trouble shoot this by phone worldwide).

Well...as far as a schematic...you can go to the patents and see that they have AGC and phase compensation circuits for a start. Filtering, pickup active preamps, switching control, pop suppression, etc...

SO...you can see perhaps why my approach is quite different. I did not seek out the solution in circuitry (mainly because while I may understand a little I could never successfully design such aspects) but in the design of the driver. Very simply, I did not really seek out the driver solution by mimicking a conventional pickup. Now the solution of the thin driver may seem too simple...it took a lot to get to that point. Mainly because I had far more complex ones before it.

SO, if you must have a neck pickup I would rather have a real pickup and a driver than a substandard active pickup and combine the two. I don't think it is a very good solution to expect huge routings in the guitar (i don't even like putting the battery in it). If I used SMD on my existing circuit it would be smaller than an inch square and most of that would be wire connection points!

Anyway...it is important for people to realize the modifications required by Fernandes and weigh that up. The DIY third option starts to look pretty tempting at some point. It is not simply about reducing cost, the DIY option allows for customization plus modification limitation at the same time! Viva the DIY Sustainer

pete

Oh and here's a video review of a new Mason Tele featuring a sustainer and a Kaos pad...wooo

The interesting thing to note here is that many of the things offered by the novel kill switch and especially the pad...it is only because of the sustainer that you'd have a hand free to do this kind of effect manipulation....Manson Kaos Sustainer Tele thingy

If you are not familiar with Vai's work with it he has it fitted to quite a few of his guitars now...here is a link to a vid Tim/onelastgoodbye sent me...

I was interested to see that he has also developed a technique of muting the strings with the forefinger directly behind the fretting finger...muting techniques are so important with this device. I still haven't seen or heard anything from Vai that fully exploits what this thing can do however...yet!!!

Edited by psw
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There are about 24 extra connections required to get those switches off-board....now there's trouble!!

Where can I find the schemtics for this? I'm assuming you have a phase reverse switch and an on/off, right? What does the on/off do? Does it just enable/disable the input to the sustainer amp, or do you have power switching and automatic bridge pickup selection, too?

The transformer could be a way to boost the driver enough to work as a pickup, or to allow a more pickup like driver to operate as both a pickup and a driver...or it could be something else...lol

Excellent point... I hadn't even thought about that. You keep saying you don't know much about electronics, but you've obviously considered every aspect of the design. I think you should give yourself more credit.

Of course the drawback is the need to remove a significant amount of guitar, the restriction on the placement of switches and you will notice that you not only loose your choice of neck pickup for the driver but the single coil bridge pickup also needed to be replaced for their humbucker...hmmmm

Yeah, I don't like the way they lock you into the whole pickup system, either. I noticed on your install that you've got a single coil bridge pickup. Is it a true single coil or a stacked humbucker? I remember the Sustainiac literature saying that they require a humbucking bridge pickup to avoid crosstalk between the pickup and driver.

SO, if you must have a neck pickup I would rather have a real pickup and a driver than a substandard active pickup and combine the two. I don't think it is a very good solution to expect huge routings in the guitar (i don't even like putting the battery in it). If I used SMD on my existing circuit it would be smaller than an inch square and most of that would be wire connection points!

Agreed. My installation is going to be a bit different, but I dislike the idea of trying to use the same coil as a driver and a pickup, too. I'm planning something like this: driver in standard neck pickup position, P90 right next to the driver, humbucker bridge. I like to keep my controls as simple as possible, so I'll be using 3 way pickup switching, and I plan to set the driver amp gain internally so the only external sustainer control will be a combined on/off and phase reversal switch (I managed to snag a couple 4PDT mini-toggle switches from work for this purpose ). As you can see, I'm one for really custom installs... the commercial systems simply aren't flexible enough for me. Of course this is a two way street... the more flexibility, the harder it generally is to install.

Oh and here's a video review of a new Mason Tele featuring a sustainer and a Kaos pad...wooo

The interesting thing to note here is that many of the things offered by the novel kill switch and especially the pad...it is only because of the sustainer that you'd have a hand free to do this kind of effect manipulation....Manson Kaos Sustainer Tele thingy

Neat. It's basically opposite of where I'm headed with ultra simple controls, but it does showcase some of the cool possibilities of the system. I've found that I usually have my hands more than full on stage, so I've been trying to move as much stuff out of my guitar as possible. My piezo-equipped Ibanez has all the controls necessary to blend and switch pickup modes in mono, but I always run it in stereo and blend to mono outboard with a blend pedal or ABY box.

If you are not familiar with Vai's work with it he has it fitted to quite a few of his guitars now...here is a link to a vid Tim/onelastgoodbye sent me...

That link points to the Manson guitar, too.

Anyway, I soaked my coil in polyurethane last night, and I'll give it another hit when I get home from work today. Hopefully that will be enough to let me do a temporary install and start getting some development done on the amp. I'm going out of town this weekend, so I doubt I'll get very far, and I really need to get some of the other projects off my prototyping board first. For now I've been using a little IC amp that I pulled out of a cheapo set of computer speakers. It's actually fairly well-suited to the task, but is far too large. I'm shooting for about 1 1/4" square on my first (perfboard) prototype. The actually PCBs will probably have to be larger to make room for pin headers and traces.

Edited by fookgub
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OK...ooops...too much paste not enough copy...

I fixed that Vai link (in the original post but not in your quote I'm afraid). Better yet, I found a much better example on the same guys video page. Check out G3 in Denver the first track in Vai's set "I Know You're Here" played on his triple neck Jem. This guy has put the whole concert up (can you do that?) so you have to move the slider thingy to 25:45 to get to the bit that most features the Sustainer.

This guitar has 12 string, 6 with trem and a fretless...the fretless works with a sustainer but the same effects (without the sliding) as far as sustain can be got from a fretted guitar. You will notice that he can play it by just hammering on notes (no picking). He seems to have a sustainer on all his guitars now and it pops up here and there throughout the concert. Vai is such a show off!!!

Now...where were we...oh yeah, sustainers...how could I forget...

Where can I find the schemtics for this? I'm assuming you have a phase reverse switch and an on/off, right? What does the on/off do? Does it just enable/disable the input to the sustainer amp, or do you have power switching and automatic bridge pickup selection, too?

Yes, and I am sorry to say one 4pdt switch may not be enough...

This is how I have wired the thing and I still get a "pop" when turning it off!!! An alternative idea is to leave the device on and switch the driver in and out and do the pickup switching...this may address the pop (tried a lot to stop it but it is from coil "backlash"), but it will always be on and so use more power in it's idle state (not a problem with remote power mind) but you will still need a bit of switching...

Now with electronic switching, you could switch everything in and out with a momentary pyshbutton without even drilling into the guitar...but hey, I know the principles not the practicalities...hence...

Excellent point... I hadn't even thought about that. You keep saying you don't know much about electronics, but you've obviously considered every aspect of the design. I think you should give yourself more credit.
Ok...I am Mr DIY Sustainer... !!! I understand what I want, I understand what is possible, I can solder a neat join, etc, etc...but I can't seem to organise my own circuit boards or get my own electronic "designs" to work too well... So many holes in the knowledge...

Is it a true single coil or a stacked humbucker? I remember the Sustainiac literature saying that they require a humbucking bridge pickup to avoid crosstalk between the pickup and driver.

The pickup is now a very cheap (A\$30) stacked humbucker...however it did work with a single coil. The driver/pickup was made from the original bridge pickup. A humbucker is probably preferable but I'm sure Vai doesn't use a fernandes in the bridge to use this thing now does he....hmmm My other pickups (neck and middle) were all true (cheap) single coils...but you will notice on the switching I had to take them right out (hot and ground)...perhaps with humbuckers... Really, all my testing was pretty much done with single coils and true humbuckers really need someone to do some experimenting with...particularly if wanting a humbucker/driver combo as we have recently discussed. I did enough work to show it was possible.

Agreed. My installation is going to be a bit different, but I dislike the idea of trying to use the same coil as a driver and a pickup, too. I'm planning something like this: driver in standard neck pickup position, P90 right next to the driver, humbucker bridge. I like to keep my controls as simple as possible, so I'll be using 3 way pickup switching, and I plan to set the driver amp gain internally so the only external sustainer control will be a combined on/off and phase reversal switch (I managed to snag a couple 4PDT mini-toggle switches from work for this purpose ). As you can see, I'm one for really custom installs... the commercial systems simply aren't flexible enough for me. Of course this is a two way street... the more flexibility, the harder it generally is to install.

Well...it's not harder really...it's just more DIY!!! By doing it yourself you have to make the connections anyway. Installing any sustainer require pretty much a complete rewire on any guitar. Making the connections on the board or on the switch is much the same...except, with DIY you can put them where you want. The circuit is much smaller too, so little or no routing...wiring is easier than routing in my book. It is even possible to make the driver so thin as to be surface mount on many guitars if there is room between the neck and the neck pickup...a strat would be a perfect example...you could even shim the neck if required...

I don't see how you could do it with one switch anyway though. You may have to rethink this. A three-way maybe (normal, mid off, harmonic) but I've never seen a switch that could do it. It would be tricky to use too! (oh and the pop...ekkk). I have been told though that fender's S-1 knob switch is 4pdt which whould be pretty neat...don't know if you can buy them without the strat though! Playing wise, it's very cool to be able to switch between normal and harmonic while sustaining a note and this function is best left to it's own switch I feel...as a player.

Certainly internal gain is the way to go...I notice Vai has a sensitivity control, but the commercial guys seem to have ditched it and I have one but don't use it. You can really control the thing by picking strength and touch, that's the beauty of the thing...

Effects...

Neat. It's basically opposite of where I'm headed with ultra simple controls, but it does showcase some of the cool possibilities of the system.
Well...i don't think much of the idea really...though the kill switch is pretty cool with a sustainer... What I was trying to get at is the posibilities of sustain with the use of effects though. Time/modulation effects take on new uses with this device and become kind of synth like, filters like wha's too can be used to manipulate long notes... Weird stuff though...I hear Fender has a tele with a laptop buit in for recording...hmmmm

For now I've been using a little IC amp that I pulled out of a cheapo set of computer speakers. It's actually fairly well-suited to the task, but is far too large. I'm shooting for about 1 1/4" square on my first (perfboard) prototype. The actually PCBs will probably have to be larger to make room for pin headers and traces.

Well a few people have done the PC speaker trick...but then they didn't go the next step to build it into the guitar and work satisfactorily with batteries. Even my prototype circuit is tiny really. The switching takes up a little room and the battery is of course always a problem. This thing will eat batteries...mine will work with rechargables though. You will need easy battery accesss If you look at some of the fetzer/ruby circuits they have been made pretty damn small...one was small even with the switches on board...very neat.

It sounds like you are well ahead of me in the circuit making department...it will be interesting to see what you come up with and if you can find any novel solutions with the installation. This really has been neglected. Just stay open to various possibilities (like multiple switching) that you may need to use and you will find a way. Test it outside the guitar, but some modifications may need to be made as there could be some unexpected effects (one that comes to mind is the fact that the driver wires put out EMI too....mine are twised and go throught he trem cavity to distance them from the pickups and other wiring for instance).

Anyway...looking forward to seeing someone else with a sustainer working so I can swap playing techniques and ideas....keep up the good work... pete

Edited by psw
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hi im new here and i spoke with you psw and all of this sustainer talk is really interesting.well i saw 1 of the schematics that you posted up here and cant make out the values of the components. could you post a bigger version. thanks in advance

i also have a question about the circuit. you said that its almost the sane as the others ,but it doesnt have a transistor.does this make the circuit better or what type of effect will it have on the sustaining if any

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JTech...ummm...no this was a circuit for just the poweramp section...

As I recall we were talking about the so called "zobel network"...that's the resistor (10ohm) and capacitor (0.1) connected between the out put and ground. The idea of this is to help stop oscillation.

This is from a kit that was further modified...on mine the output cap is now 100uF (not 220uF though this also works) pins 1 and 8 are bridged with that 10uF cap (no 1k resistor). There is a 100uF to smooth the power supply (I also added a power protection diode), a 10uF pin 7 to ground and a 10k pot for sensitivity (gain) control...

But all this is fairly standard kind of LM386 circuit...the ruby is not that much different in the LM386 poweramp section. It will even work with just an output cap (as ansil spec'ed in his infamous sutainer mod project...which I used in the first experiment on page two i think).

The problem is and always has been the preamp section. The ruby uses a single transistor "fetzer valve" to provide a buffer and a little gain. Mine has two transistors, filters and a lot more gain. A preamp is very necessary to stop loading on the pickups. I seem to experience no loading problems...but most who have looked at it are surprised and think the design should be a little different...more like the Fetzer in fact.

Oh well...anyway, I now realize that I haven't put up the preamp here and that it had, like the above circuit, undergone quite a few little modifications. I am was not sure of the mods till recently actually. My preamp adds a bit more size to the circuit than the fetzer/ruby...next time i suspect I will be trying this to compare.

I don't know how many times I have said this already...but...THE "SECRET" IS IN THE DRIVER DESIGN.

The circuitry is very much just a very simple amplifier. Notice that fookgub used a computer speaker amp with some success. Even a very basic LM386 like the one you've put up there would work...or simpler...but it won't sound good. The whole idea is to not change the sound of the guitar...a loaded pickup will have a dramatic loss of volume and tone. You may get sustain and prove that the driver works...but it won't be suitable for a proper installation.

The temptaion to treat this thing like some kind of fuzz box with Voodoo qualities is just too great. Once you start down that road the circuit will only get bigger and more complex. I have approached the driver design to compensate for phase (by very fast operation) and there should be plenty of gain with most pickups to give some compression.

Until I have developed my circuit further, I am keeping that side of things to myself...but that is not because mine is better necessarily (I am looking at changing it completely), but because I am looking to develop it further. But, due to personal circumstances I am doing no practical work on the sustainer at present myself.

I wouldn't want people not to experiment either...that's how this project can evolve. Some have used a fuzz as a preamp and i used a very clean limiter/compressor at one point (worked great but a bit big). Otherwise, I believe that the fetzer/ruby has worked fine and some have suggested that it is technically better than my bigger and more complex one!!!

The main thing is the driver...get that wire potted around a core and slap a magnet to it...and give it a go...if there is a problem, it's most likely there. You can test the amp with a speaker of course and you will tell if it is loading the pickup by the loss of sound. The really tricky part is installing it into a multi-pickup guitar like mine...but then the switching for that is above...most guitars will be a bit easier than a strat.

Without wishing to offend anyone, most are not experienced enough with scratch built circuits, as easy as the fetzer/ruby is, that they get into a bit of a panic or can't locate the parts. It is an easy circuit but mine would really confuse people more. That's why I am keen to get a circuit board or even a kit made available to people so that there is a standard ciruit available...but that could be a while off (my ex still has my soldering iron for a start!!!)...unless I get some more serious assistance. I'd also like to test a few more ideas, fix that pop and maybe even see if there isn't going to be easier to have the thing made with SMDs for something really tiny. But don't let that stop you...even if the circuitry is significantly improved sometime, it could be easily swapped out later...cheap too!!

Great to see so much interest...keep at it. For encouragement, you could build the driver and drive it with any low powered amp...the magic of seeing the thing work will be the best encouragement. Perhaps some others if they are still following this, could offer some advice and experience doing this...

good luck... pete

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Great to see so much interest...keep at it. For encouragement, you could build the driver and drive it with any low powered amp...the magic of seeing the thing work will be the best encouragement. Perhaps some others if they are still following this, could offer some advice and experience doing this...

Pete's right... For initial testing, any old amp will do. When I first wired up my coil, I just plugged it into the external speaker out on my little 15W Fender amp. I'd like to toss in a word of caution, though: don't do your initial listening tests with a high-wattage amp! If you run into oscillations, you can really blow your ears out. I should know better by now, but I did this just a couple weeks ago when I was experimenting with alternatives to piezos. I had a small dynamic speaker clamped to the body of my bass and I was playing it fairly loudly. I decided to see what a different speaker sounds like, so I flipped the mute switch on my amp, hooked up the new speaker, hit the mute switch, and EEEK... feedback. Trust me, you do NOT want to find out how loud a ~2kHz tone can get through a 400W bass rig. My ears rang for the rest of the day.

Anyway, back to the sustainer. I made a little progress on my sustainer today. I tested out the "potted" coil, and it's better but still not great. It will oscillate if I get it too close to the other pickups, and I can still hear some sound directly through the coil. I'm still testing out of the body for now. The rest of the stuff I need for the installation (pickup, mounting rings, and a 3-way switch) is coming on monday, so I'll be able to actually install the driver and do some real testing. I think the polyurethane I used on the driver is going to interfere with my ability to vacuum pot the driver, so I'll probably have to rewind it. I'm still having trouble sustaining the high strings, so if I do rewind the driver I'll probably try Pete's recipe with about 100 turns of 32 AWG wire. Again, I'll have a little better idea of what to do with the coil when I get it mounted and do some better testing.

Last time I wound the driver I spent about an hour machining a bracket to mount it on our transformer winder, but now that I have that done I can wind a driver in about 5 minutes. Potting may take longer (I need to get someone at work to show me how to use the potting machine), but I could be in the position to try out a whole bunch of different coil configurations with relative ease.

As far as electronic switching goes, there are some IC's out these days that are pretty easy to use. Much better than the old Anderton electronic switch from EPFM. An electronic switching system would need to be done on a PC board to make it convenient, and it wouldn't save much on wiring mess (you'd still have to connect everything that'd you connect to a mechanical switch), but it really buys you a lot of options for switch types. You could use an SPST momentary or latching, and these are available in almost every type imaginable. We'd be able to design out the pop that you've been having problems with, too (btw, Pete, you've got pm).

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Thanks Fooks...

There you go...but be warned...if you look at my first post you'll find this...

Many years ago I wound a crude coil and ran the guitar output to both my amp and a trashed hi fi amp. The output of this went directly to the coil placed beneath the strings. It worked!!!!!!!!!!!! However some notes better than others, but still it worked!!!!!!!!!!!

Only one drawback. Within minutes the coil heated up like a bar radiator and proceded to melt the electrical tape holding it together. The strings really heated up and the whole thing threatend to catch on fire! Still it worked!!!!!! I've got some recordings somewhere to prove it. Would make a great stage act!

That's right, I invented the electric bar radiator heater!!! 400 watts, even i didn't do that...the above was probably only about 10....sheeesh...

Anyway...take heart....

Testing the device above the strings is worth while, but it is so much better installed. You are holding the device above the strings and so also above the pickups. Installed it will be on an even plane with the pickups at least and the EMI will be less for it. You may also find as I did that you will need to switch both hot and ground out of all wiring bar the bridge pickup and controls (hence my 4pdt switch) to avoid a signal being sent via the earth through the un-used nearby pickups that seem to act as ariels for the drivers signal, sending it to ground and causing noise...well, that's my reasoning for it, either way, this fixed it.

The pop? I'm sure there is a way...but I haven't found it yet. Switching out the driver would be the most obvious solution...maybe leaving the circuit in idle. Bear in mind that this pop is only when you switch off, not on or mode switch.

The big attraction to electronic switching would be to simplify the off-board switching. This is one device where push buttons would be good on a guitar. I could see something small enough to fit into the edges of a humbucker pickup ring. A momentary control would be cool to, to add the effect stealtherly to single notes for instance.

This type of thing was explored way back for those who have been around a while. If you recall the box ideas (mid 30 pages I think) I built a switch behind a pot so you could lean back on the sensitvity control to add sustain at will. SOme of my hex designs also featured such miniture controls...anyone remember this one?

This one has a momentary switch (on the left) and two leds (the small dots on either side of the six poles)...

Ah yes...but we will not be going down that road again for a while. This work on building and envisiging such devices would be a shame to loose and it shows a glimpse of possible futures for such a device. As far as the current DIY project, the important thing learnt from building these tiny things is that the thin driver has inheirent design advantages to more pickup looking devices and the complicated circuitry to drive it. Rather than get too fancy with the driving circuit, I think some kind of electronic switching would yield far more benefit.

But, with this I am way outside my comfort zone and resources. I welcome anyone who'd like to get into this aspect further. For now the simple DIY single coil sustainer works a treat, it would just be nice to get it standardized so as people can be fairly sure of success if they follow the steps and put the time into it. It really is pretty simple...I am just amazed that someone doesn't already have a kit for a LM386 or equivilent battery powered amp with high impedance preamp...someone should design something like this if only as a preamp!!!

Thanks for the encouragement...oh, and fookgub, what are you using to power this at the moment...something a little lower powered I hope...it really should only take a half watt or so...haha

pete

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Theres a preamp pedal called the "Behringer PB100 Preamp Booster pedal", could I gut it and stick its innards into my guitar, and use that to drive the sustainer that I want to build?

Thanks.

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Potentially Ben, but you will still need the LM386 poweramp stage like JTech posted above. The preamp itself is not designed to drive a speaker but would serve as a preamp. People have also used such things as distortion boxes for the preamp stage. The main purpose of the preamp is to prevent the loading of the pickups and to provide a hot signal to the poweramp. Therefore, there is no reason that this would be any better and would be more likely more difficult to do than the simple little fetzer/ruby circuit that only adds a couple of cheap components to create this effect, and you would still need to build a poweramp anyway. What this amplifier is most like is a very small practice amp.

pete

PS...welcome Ben to the Sustainer Thread...

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I don't know how many times I have said this already...but...THE "SECRET" IS IN THE DRIVER DESIGN.

good luck... pete

yes i agree with pete.. i believe those amp designs are made with their proven point some way... so i think they will basically act the same way- TO BE AN AMP! because thats what they are... now i believe we will be able to do better than pete's version someday IF we understand how everything works so what we need to do now is to start from scratch and basics and dont even try to follow pete's or anybody's 'much advanced innovation' because it will only confuse us much more... what we need from him and from other pros are the precious advices that they are providing us right now. if pete says THE SECRET IS IN THE DRIVER(i already read this line half a million times when i dared to read from page 1 till 79, nobody listens to him until then...), then lets go study the principle of the driver!

now, i wanna share my little experiment from now on...

but first i wanna have all your possible comments or suggestion with this:

i am building the fetzer-ruby right now and the circuit seems to be perfectly built(with a big help and inspiration from pete).. now what i have on the neck is a generic hum(i dont wanna wreck my dimarzios!), with an NPN magnet between its poles.. what i did was, i removed the other half of the hum to make it single then i am planning to share the NPN magnet of it with the driver's 'core' (as soon as i get it from the machine shop where i specially ordered them to do) with the dimensions following pete's suggestion (3mm x 10mm x 5.6mm) just a little taller to follow the height of the 'ex-hum's' poles.. now i used the other half of the hum's bobbin as the bobbin of the driver so it will still be uniform and to minimize the alteration problems with the guitar.. i will never know if this would work not until i put on the driver.. well i hope this works fine..

my purpose here is to give everybody an idea on the design or planning part of the project.. i hope this helps...

if i successfuly made it i will as well post pics in the future...

rock on!

p.s. pete, please give us an advice on where to connect the on/off switch best as well as the led to make the most out of the sound or to prevent it from interferring with the power..

thanks!

Edited by starry_night
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ohhh...simultaneous post...it's 6am here...lol

Anyway...

if pete says THE SECRET IS IN THE DRIVER(i already read this line half a million times when i dared to read from page 1 till 79, nobody listens to him until then...), then lets go study the principle of the driver!

I wouldn't say nobody listens...the fact is that there have been some fabulous drivers that follow the general idea of the thin driver with success. It is only when this has been comprimised (different wire, lack of potting, etc) that a lesser performance is experienced.

p.s. pete, please give us an advice on where to connect the on/off switch best as well as the led to make the most out of the sound or to prevent it from interferring with the power..

Ok...the LED will need a pull down resistor...i forget the value...so as not to burn out the LED. The LED will go on if it is connected to the circuits power when the power goes to the circuit. The LED will not cause any noise.

The driver leads could cause noise problems. The leads are effectively an extention of the drivers coil. Use ordinary wires (not too thin) and twist them together. Twisted leads help balance out the alternating EMI in each lead. Additionally, I ran the driver leads through the trem cavity on my strat...but not everyone can do that. In the end the driver leads will have to go to the circuit and the harmonic switch and these are likely to be fairly close to the guitars wiring. My guitar has sheilded cable from the pickups too for noise reduction, and this may also be helping reduce noise.

The extent to which all these things need to be done is really up to experiment. Bear in mind, in my guitar I have 3 pickups and they are low quality single coils at that...as long as the driver leads are twisted and generally lead clear as possible from other wiring in the guitar...it shgould all work out ok... pete

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Thanks Pete.

I think that since I cannot really afford to perform experiments that will not work, I may be wisest to copy a sustainer design that someone else has built and got to work successfully. I have been reading bits of this thread for a while now, I know the basics; short, fat coil, thicker wire than normal..etc, and I understand the principle behind the idea, so I will most likely give it a shot in the coming weeks. I shall post any results.

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Use ordinary wires (not too thin) and twist them together. Twisted leads help balance out the alternating EMI in each lead.

pete

wouldnt it be adviseable to solder the leads to the wires? will it be ok if you just twist it without soldering? or should we avoid soldering it?

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