Physical feedback?

[Peter Snowberg]

I know the idea of using a pickup as a motor winding has been applied to creating sustain. I've seen mentions of using a neck position pickup to drive the strings and I remember ads for a product that involved bolting a small box to the neck, right under the tuning machines.

Has anybody done this in a DIY context?

Maybe a pickup core without the magnet, and rewound using #30 wire, going to an LM386? I can just imagine that with a digital delay, trying to add notes from the past, but filtered by the finger positions and the string action of the present. So much for a sterile feedback loop.  

-Peter

[Mike Burgundy]

I think the more succesful DIY undertakings involved a small speaker mounted to the headstock or other part of a guitar. This is basically what that headstock-mounted box is I think: basically  a magnet and a speaker's driver-coil. Actually quite easy to experiment with.
Constructing an EBow is really, really difficult, but I do seem to remember something about people using pickups (which, btw, is what the Fernandes system does)
hih

[gez]

I reckon a Soundbug might do the trick.  It converts any surface into a loudspeaker.  Stick one on your guitar's body close to the bridge, feed some of your signal back to it and away you go!

http://www.soundbug.biz/

[petemoore]

You're talking about the pickup driving the string into vibrating using magnetic force?
 I didn't quite follow...interesting concept [electromechanically driving the strings like a speaker on headstock but with oscillating magnetic force driving the strings] but seems like it might be hard to get enough drive then you'ld have one heck of a electromagnetic noise inducer too ...
 Doesn't Ebow somehow magnetically mystify the strings into oscillation? Never quite understood that too well.

[bwanasonic]

I suppose you could try to reverse engineer one of those Fernandez Sustainer pickup assemblies.  My favorite DIY method of physical feedback is  a lot simpler - it's called VOLUME!    Frank Zappa used to have parametric EQs built into his guitar so he could *tune* the feedback response.  I've always seen the E-Bow mentioned as impractical to clone for DIY purposes, but I wonder what's in that little thing. If mine stops working someday,I'll smash it open for *research purposes*.

Kerry M

[R.G.]

1. Decide to sacrifice a pickup (this is not a small task; maybe a buy a cheap replacement from ebay).
2. Remove the pickup, cut away all the hair-fine wire in the bobbin space.
3. Wind the bobbin full of #24 or #26 magnet wire. About 200+ turns is right.
4. Put the loaded pickup back in the guitar. Neck position is preferable.

Drive the sustainer pickup with an LM386 amp-chip at high gain, using the guitar's output jack as a source.

At least parts of this approach are patented. Apparently you have to get to a few-turns, low inductance coil on the pickup to get the driver votlage down low enough for battery voltage drivers to do it well.

It may eat batteries a lot.

You could still use this as a normal pickup (although not at the same time as when it's a sustain driver) but you will have to use MONDO gain to bring its now-small output voltage up. Fancy switching and onboard electronics are probably needed.

[Ansil]

How to make a sustainer pickup  

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1. Decide to sacrifice a pickup or buy a piezo speaker from radio shack, the nice little flat ones that will fit under a humbucker, or the smaller one that will fit under a strat pickup,  aproximately 5$
2. Drive the sustainer pickup with an LM386 amp-chip at high gain, using the guitar's output jack as a source.

IF YOU USE the 386n-1 at 6v it takes up less batterie power.
You could use this as a normal microphone but with mondo gain it will really squeal.

[petemoore]

Er some Ted stuff where you want the note to sustain into a harmonic of 'it's', or your choosing.
 Press the head of your guitar to the ledge of the cranked 4x12'' cab [2x12'' on a chair?]...Perfect for the end of the lead in ACDC's 'Livewire' etc. The Cab must be producing enough [of the right] vibration to work well but I've done it at 'reasonable' volume levels.