Jump to content

Recommended Posts

Prototyping as I understand it, is putting together a solution, whether refined or the best as you can do with your resouces, to show the solution to someone as close to how it would be as a finished product as physically possible. Testing is just making sure something works or does what it is intended to do. You can test at a lot of different stages, before prototyping and after.

Link to post
Share on other sites
  • Replies 4.7k
  • Created
  • Last Reply

Top Posters In This Topic

Top Posters In This Topic

Popular Posts

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

That's right, but you have to consider in this type of device there are both active and passive components. Some of my prototypes simply wont work without the "packaging" and just about all of them will self-destruct before long.

The drivers consist of active components that work on a passive magnetic field. This is very suseptable to the type of materials around it (it's "environment" I think I called it in a previous post) and this is very necessary to the design.

I got up and had a bit of a play with the prototype and immediately achieved tremendous results holding the device directly above the strings over a pickup. However, it was a little too long (hit the height adjustment screws) and high (couldn't really get it under the strings properly) so I had to file off a lot of last nights work. Hopefully, after recoating with a secret material, these modifications will fix these problems.

On the circuitry, I've also changed to an earlier test circuitry. I have been using a compressor preamp/amp combination for some time as it has automatic gain control and several other features I thought may be necessary. This old circuit fits in a small jiffy box taped to the guitar and works just as well on todays testing. That bodes well for a simpler drive circuit thats small and cheap.

We'll have to see how fast it eats batteries though, I'm still running it from a 9v power supply. This circuit has run very early designs on a 9v battery before so I'm hopeful. Also, I have a rechargable 8.4v to test that so that perhaps I could just recharge the guitar by plugging it in for a few hours rather than take out a battery and pay for a new one every couple of days.

Anyway, everyday another step closer.


Link to post
Share on other sites

Here it is, opinions please...yes it does work!

homemade strat with driver attached to mid pickup and circuitry in little black box behind bridge....


Here's a side view...


and again in close up...


a bit rough, but it's getting there!


Link to post
Share on other sites

It is looking very good. Although i'm just wondering. Is that black box just there now for prototyping or hiding the circuit? Because I doubt many people would want a black box stuck on the side of their guitar. I dont know, just my thoughts. But it's definately looking good.

Link to post
Share on other sites
...I doubt many people would want a black box stuck on the side of their guitar...

IIRC, the original concept was to make the sustainer removable, hence the "black box" - for a permanent installation, it would be unnecessary. It should be fairly obvious why you wouldn't want to make your prototype a permanent installation.

Looks great! You mentioned a special secret coating - you're not using C37, are you? :D

Link to post
Share on other sites

Thanks guys

I posted this 'cause, well we got ourselves a digital camera for xmas so I can now, and, there seemed to be some concern at how it would look or even to quite grasp the concept of this incarnation of "The Project".

By the way, any thoughts on a name for this thing?

Ok, firstly, there is a special coating, and it's secret for obvious reasons, so there!

Now the black box, well I'm sure you could get something in red. Seriously, as LK said, don't prototype stuff in the guitar. Actually, I had thought, if the circuit and controls could be made small enough, the strats jack plate could be incorporated into it and the sensitivity control come up just behind the volume. The battery could be installed down the hole...well it's an idea!

The thing could be painted, I use nail polish (not on me, quit laughing), originally it was black but that all came off when I had to file it all down again. I have some embossing foil so I think I could make a fake silver or gold finish.

Now, yeah, part of the concept is that it be removable, but not easily! On this prototype I've taken the wires out top and bottom. the idea is to file a small groove in the scratch plate or pickup cover for these to enter the guitar. These wires would be taped to the cover under the pickup to help hold it on. This example is held on with double sided tape. I've taken a wire out directly from the bridge pickup that comes out the back and connects to the black box under the yellow tape.

Conveniently this guitar has a "soundhole" to bring the wire through. It also has an unusual wiring scheme..the three switches are phase for each PUp and the gibson style selector selects bridge, neck or both. The tone under the volume controls the volume of the middle pickup. Bringing this in either thins out the sound for quack or adds body depending on the phase selected by the mid switch to any combination. The point is though, I am able to turn off the mid coil, as it happens on this guitar, for testing the device.

A conventionally wired guitar will need easy, but quite a bit of wiring modifications. Your also going to have to drill holes for the controls I fear.

Sound clips are possible but my computers ancient and the samples always seem to take too long to load. I also need to record them to cassette then run them on a little recorder, so quality is very low.

Also, the circuitry is still a little temperamental. I'd like to fix this up a little first. The first problem is that there is simply too much gain! Easily fixed and bodes well for it's efficiency. It also favours the bass strings so I need to adjust it's frequency but I get high frequency oscillation when I do. I need to get a little more sophisticated with the circuit (and a little help) and/or work more on the driver design to compensate for the mass off each string.

It does respond quite well for chord work, at least in a blues rock style, having quite good string drive definition and keeping each string ringing for quite some time before the lower strings predominate.

One reason for choosing the mid position by the way is to ensure that the strings, while string bending, stay under the influence of it's own driver. Some interesting effects occur though when they do that I didn't expect that's really cool and unique to this type of system.

Anyhow, see what I can do in the next few days, I'll be away for a week so we can all rest from my super long posts!

Thanks for your interest, it's really encouraging, I need that at the moment.


Link to post
Share on other sites

Would it be possible to put the sustainer in a pickup mounting ring? It would have to have a special mounting ring with the sustainer side higher up, but if the sustainer is small enough and the placement of the sustainer works there, it should work.

Here is a diagram of what I mean:


Link to post
Share on other sites

Well I can't find it now Mr. Vai...

but somewhere I put forward just such an idea. It would be the obvious solution to mounting it. There would need to be a bit of development as it would no longer sit between the pickup's magnetic field and the strings but I have some ideas for working around it.

Nice graphic though, if I spent a little more time with graphics than words I could have saved myself a couple of thousand and everyone would know what I was talking about a lot easier!

How about some ideas for control layouts...looking at at least 1 knob and two switches



Link to post
Share on other sites

OK, I've connected the black box to a 9volt battery and am running the power amp on minimum gain (x20). Seems to work just as well if not better and gives me more of the pot to play with so adjustments are more subtle.

More importantly, it brings the guitar back into the lounge room so it'll let me have more time to play with it :D

Presently, it works best in harmonic mode...that's where notes peel off a harmonic above after a given time. It's kind of neat to just play with the thing on and let any sustained notes peel off like this while shorter notes play as usual. Same with sustained chords.

keep you guys posted


Link to post
Share on other sites

Control Options

Push pull pots could work, some could say they're inconvient, but for switching on and off a sustainer, I think it's pretty much the same as a dedicated switch. A pot that clicks off in the 0 position (not sure what it's called) could also combine on/off and gain/volume in one knob, and might be more convienient. I don't know if they have these pots designed for guitar (probably can find something close enough), but I'm talking about the pots they have on some cheap radios, computer speakers, etc. Using push pull pots or pots that click off and dual concentric pots, here's what I would do: (push pull pot could be replaced with pots that click off)

1 volume: Existing volume knob replaced with a push pull pot, and new push pull pot installed

1 volume, 1 tone: One replaced with a push pull pot, and other knob replaced with a dual concentric pot (may have to give up tone knob or install new knob)

3 knobs (Strat): Two knobs replaced with push pull pots, another knob replaced with a dual concentric pot

4 knobs (Les Paul): Two knobs replaced with push pull pots, another knob replaced with a dual concentric pot

If people don't like the look of a dual concentric pot, then they would need to install another knob or give up a tone control. If they don't like the push pull pot, they could install a new switch.

There is probably a supplier somewhere that can make pots with many controls, which would make sense for 2 and 3 control guitars. For a 1 volume control guitar, there isn't any practical way around installing anything new (except a concentric pot with 3 or 4 controls and 2 knobs/switches in 0 position. How's that for complicated! :D)

I hope this all makes sense.

Edited by Steve Vai
Link to post
Share on other sites


Testing, Testing, Testing.

One bad thing is there's a lot of heartbreak, disappointment doubt and disillusion in the process....

On the other hand, plenty of pleasant surprises...

I played around with the circuit but I'm not entirely sure what I'm doing so I've put it back. I'm testing with a battery and still working so that's good.

One problem is with string bending. As there are six drivers, when bending a string it leaves the influence of it's own driver and comes under the influence of a combination of it's own and the interaction of the one next to it.

I did some experiments with even more drivers, but this is getting expensive and I have to travel to get them.

Today I done some experiments with converting the prototype to an independent driver with some really good results. Using an unusual neutral magnetic orientation I was able to mount the driver up near the neck and make use of all pickups and combinations. There was also some other unusual effects and it appeared that it's drive may be more intense for this conversion and make the pickup top version obsolete.

There were a number of different effects that relate to the ultimate potential of the device, the ability to change the timbre of the instrument, what I've called a "natural synthesiser". Bell like tones, whistle, and reedy effects were observed without even inserting effects into the chain. These types of tones make up the building blocks of synthesis. It will be quite some time before this could be exploited, but it does show that the principle of using a driver to change the way a string vibrates to create different sounds is possible. Exciting stuff...

But, I have to stay focused on the immediate goal, which is to get a practical sustainer working. I thought I'd come across some major problems the last few days but today's experiments have been very positive.

On the subject of controls, I always liked the idea of a momentary push button which could activate the device while being held down for the odd note here and there. I have found a push on, push off illuminated switch 4pdt which looks promising and pretty cheap for the main on switch.

Oh, and it looks like a low action will be something of a must. I use strings with 10's on top and on this guitar a fairly high action. The problem is that this means that strings fretted down low are higher than those on the higher frets in relation to the driver. The result is an inconsistancy of response that is more important than pickup height and the like.

Anyway, I need a rest so it's off to the sun and surf for me and a little hidaway far away from everyting in the forests of south west victoria, Australia for a week. leaving in a few days.

See ya later,


Link to post
Share on other sites


I've promised to forget about all this stuff and just spend time with the family. So, I sneaked a little time here and there and have built a new driver. This one has it's own magnetic field and a new construction method that makes things a little easier to construct. All seems to be well with it with a little testing that I've done. It has some unusual properties that set it aside from current sustainer systems, mainly because it is a hex driver.

Anyway, I've got say I'm really proud of this one, its as small as it can possibly be...6mm wide 75mm long and 4mm deep. Its about as big as the last one but includes a whole hex magnet array. B)

But of most importance for some is that this one is aluminium, polished so as to look exactly like bright chrome. It works particularly well on the neck side of the neck pickup, right up against it (not on top). It will work in various other places but not by the bridge for reasons discussed previously. You can choose pickups, but the sounds are not what you would expect as the driver has a radical influence on what comes out of anything but the bridge pickup alone. This is not really disappointing, as these sounds are really interesting and musical, but will require people to rethink this side of operation.

Anyway, more to come, hopefully I'll be able to refine the circuit a little and really explore the device from a player point of view!

See ya guys in a week or so :D


Link to post
Share on other sites

28 pages. That's twice as long as when I started following this thread. First, I read through the 14 pages that had already written, and since then I've been following it (keeping an extra browser window open at all times and reading any updates as soon as I see them). It's pretty interesting, and it's awfully nice to see the progress made! Keep it up psw!!!

Link to post
Share on other sites

Gee Thanks G_urr_a

Lucky I can type a little...anyway, I'm keen to see this story come to the end of at least this part of it's development and it's really getting there.

I'll post a photo of the newest version soon, but while I've been away I've read up on electronics :D and I think I've got a handle on how to proceed. Still not sure how or where to install the controls on the guitar, but well see what works.

Anyhow, just a short post to let you all know that I'm back, slightly sunburnt and still salty and sore from the surf B) . Some good waves down here lately, maybe a Tsunami effect, who knows, seemed to be a very high tide too!

See ya later :D


Link to post
Share on other sites

Just to follow on from the last two pics. Here are two of the prototype in it's working position. Obviously the yellow tape is not how it would be fitted. Double sided tape under the driver and the wires on either end throught two holes or brought down through the pickup cavity should hold it nicely. You can see also the 9v battery taped to the side of the black box.


The "thing" now works from this quite happily so far. Which reminds me, I need to come up with a name as "sustainer" is already taken...any ideas?


Anyway, tested it out last night, after a little fiddling about the thing really screams! :D


Link to post
Share on other sites

Thanks Bio...I don't know sustainiac always sounded a little cheesy too!

Took apart the birds nest of circuits that reside in that black box so things are a bit clearer and I can start doing some experiments to get the thing working a little better. Also took the neck off and placed a couple of icypole sticks under there to raise the whole neck about 2mm. Action now is pretty low and that's how it's got to be so that the distantce from driver to string is consistantly close...how close?...real close, say 1-2mm from the driver.

This driver though is independent from the pickups so you can adjust them as you like but the bridge pickup should also be pretty close.

As for pickup selection, well some unexpected effects have arisen. The bridge of course. When I opened up the guitar last time I replaced the bridge pickup with a stacked humbucker...real cheap one (A$30 new)...but I thought it might give the device a bit of help by cutting out on noise. Some of the middle pickup can be used and I can do that on this guitar as the middle knob fades in the mid pickup in any combination or phase.

The neck pickup is the surprise. what you get is a huge increase in volume as the driver and the pickup act as a wierd transformer. The neck pickup picks up the vibration of the string and the vibration of the magnetic field of the driver. The driver, being connected to the bridge pickup what you get is a heavily amplified neck, bridge and driver sound...and infinite sustain. The volume is so loud that it will only work with careful manipulation of the amplifier gain and frequency impedance. The result is that only a little gain is required to get the effect. Little gain means little power requirement as the fields are kind of feeding off of themselves kinda.

So, at least at this stage, you may not get pickup selection in sustain mode but two distinctly different sustain effects plus harmonic drive in each mode. Remember though that you get a system thats small, requires minimum alteration to the instrument to install and you get to keep your own choice of pickups as a result. The action will have to be low, and generally people do have fairly low actions these days (unless your into SRV style), I'm just a little old school with this guitar. My Les Paul has a perfect action for this and I suspect the other systems will require this too.

As for the circuitry, if I leave the driver as is for now (there are refinements that could be made but they can wait), I need better control of gain and high frequency filtering, mainly for oscilation control and to get an even response across the strings. This thing loves the A string and it will vibrate this merrily before all others and dominate if you let it, string damping technique is a must. I'm also having trouble getting the thing to vibrate for long in fundumental mode. The note very soon jumps up an octave and in harmonic mode two octaves. This may be a product of the unique driver design or lack of circuit control.

Anyway, got to run

hope everyone has got a handle on the current concept from those photos anyway...


Link to post
Share on other sites

Thanks...encouragement and opinions at this stage are the biggest help!


I've been playing around with the circuitry a bit and I'm kinda getting it under control. There's a lot of unexpected noise that need to be filtered out and the different pickup settings have amazingly different sounds and effects but not what you may expect. The neck pickup setting has an amazing amount of boost and distortion of a really interesting type. It really needs to be toned down to be useful however.

It's not a smooth mellow sound, as you might expect, but a strident trebely singing sound. This is because the neck pickup is mostly picking up the signal from the bridge pickup as transfered, like a transformer, into the coil of the neck pickup. So what you here is the sound of the bridge pickup, the amplification (which is immense!), the driver, the neck pickup and what it senses of the string itself.

As for controls and set up. A direct line from the bridge and neck pickup needs to be taken to the control circuitry. A return signal back to the guitars circuitry where the pickups were previously connected. A line out needs to go to the drivers and power in from the battery. There will need to be a few trim pots. I had an idea of building it into the tremolo spring cavity cover and squeezing the battery in there some how.

As for controls then, you're looking at an on/off switch, a harmonic select switch, and possibly a pickup mode switch. This last switch would be needed as an alternative to the normal pickup selector. Current sustainers have a sensitivity knob which controls the gain.

I was wondering if the settings couldn't be preset by trim pots on the back of the guitar, adjustable with a screwdriver through the trem spring cover and intensity be refined with the guitars volume and tone on the fly. This would do away with the intensity knob and the effect could be preset by the two switch positions then activated with the on/off switch leaving pickup selector in active. Turning off the device would return you to your previous setting or wherever you've changed the selector during operation.

So for controls your perhaps looking at a trio of switches. An alternative would be two switches and some circuitry to adjust for each selection position. One problem with this is that the boost function would be in the bridge selection position and there may be a few switches to adjust to get to the sound your looking for.

I'd like some opinions also on LED indicators...I think an on indicator is essential. It could be fitted into the driver as I've done befor (in fact the whole driver may be able to light up) but other settings could be indicated too. Some other control options could be some kind of single rotary switch (tricky) or electronicc switching operated by surface mount momentary switches built into the ends of the driver or on a separate external contol panel say, down by the bridge. This type of control option will probably need several LED's or multi colored LED's to tell you where you are. Any thoughts or other suggestions?

I have to say that "it" is really sensitive to technique. String damping is important of course, just like playing super loud, but the strength of picking and things like vibrato have a big effect on harmonic change and sensitivity. It will take a bit of getting used to but I dare say it opens up new doors to the instrument that have not been there before.

For instance, I was playing a bit of a blues riff with the "thing" on low and the only difference was that if I lingerd on a note for a little longer (say 2-4 beats) the note would slowly evolve into the octave above as it decayed. When this happened could be effected by vibrato and this could technique could be used to coax the note back up in volume.

What I'm getting at is that the device does'nt have to remove the decay of every note which, along with attack gives a note it's shape. What it will do is give access to other decay shapes and effects. It will also radically alter attack to the extent that you can make notes appear from nowhere just by placing your finger of the fret and giving the string a bit of a wiggle! Of course you can get a synth type sound where there's no decay till the note's stopped, but I play guitar because I love the detail in the sound and relish the subtle differences that each guitar (and each guitarist) has in sound, and I'd be wasting my time building something that would remove any of that.

By the way, the test guitar in the photo uses a similar presetting idea where the three mini switches set up the phase relationships and the gibson style selector switches between the preset three sounds. So typically, when playing a song, you already have the sounds set up for the main toggle. The mid position being the novelty one if you like. On this guitar, the middle pickup is treated as a tone, fading in that phased knophler/quack to taste or, with the phased reversed, a more powerful midrange presence.

I've found that the mid pickup is and, especially, the phase relationships are critical to the sustainer's successful operation. (Mostly I have the mid pup off to make things easier). Every change to the signal into the device needs a completely different set up for the circuit, and with the neck pickup, because of the boost effect, the output of this pickup back into the guitar will need to be attenuated too. That's a lot of variables. Effectively it will need to be tuned (by these proposed trim pots) to each individual guitar.

Anyway, finding room for three mini switches is probably easier than a pot and two anyway. Tell me what you think.

On the driver side, there maybe a refinement or two to make the driver array more efficient. I've experimented with a few things and have developed quite a bit of knowledge from the many, many, many hours of work I've done on this (it better be worth it!). It will need to be a little thicker (say 4-5mm) to implement them though. I have an idea for making it slimmer (say about 3mm) but it would need to be about 5-6mm thick. With a strat you can chock up the neck or route into the pickguard (thats 3mm right there) rather than stick it on top. (That's a bit much for your average DIY installer I imagine). On most set neck guitars it's probably not enough space without letting it into the top.

I like the pickup ring idea but as I recall there isn't much more (if that) than 3mm from the fingerboard height to the top at the end of the neck. Perhaps you guys could check out your guitars for me. It may work fine on the bridge side of the neck pickup though, I'm not sure.

That also brings up the question of humbuckers. I've been testing the "thing" on single coils (although the bridge pickup is now a stacked humbucker). I really don't know how the device will interact with their dual magnetic fields. I can say that my present device doesn't like to be moved to the otherside of the pickup or to be turned around. The reason seems to lie in the particular polaritiy of the driver and pickup.

The humbucker's complementing fields and coils may actually improve the situation but then maybe not...that will be a whole nother enquiry. Certainly there is enough room in the Les Pauls control cavity for the circuitry, but that's a pretty thick guitar....I'm not so sure how much room you'll have in other instruments. I'd rather not have people digging into there instruments if I can help it, people seem to have difficulty enough with wiring changes!

Anyway, keep the interest alive and I welcome any suggestions anyone has!

Hope I haven't put anyone to sleep with my typically long post...I suspect that secretly people enjoy reading a saga every now and then


Link to post
Share on other sites

Hmmm...no comment?

Anyway, I've been trying out some ideas for placing the driver just ahead of the bridge. This is problematic...the harmonics are complex here and the string harder to move. On the other hand, it's probably a preferable position as it's out of the way, close to the control cavity, there's a bit more height so I can design in more efficiency (perhaps), magnetic strength has less effect on the tighter strings so stronger magnets could be used.

I can report that I have been able to succeed in driving the string from this position. Whether it's truely practical, as more power of some kind will probably be required and the physical difficulties need to be addressed, remains to be seen.

I'll continue to explore this avenue a little. Let me know how much I shoud pursue it though as I don't wan't to waste more time on it if people really aren't fussed.


Link to post
Share on other sites
This topic is now closed to further replies.
  • Create New...