From what I found, I was getting a signal level much less than a microphone, and boosting it at least 80db, maybe more. I wonder how that compares to a guitar amp wound up high? I think the right circuit may start with a high gain transistor set up with very low input impedance to ground. I think a circuit like htat could provide say x100 gain, after which the signal will be large enough to go to a mic preamp set at more normal levels. To get a result that is not a heap of noise, I think we need to take advantage of the extremely low output impedance of this 'string transducer', and trade that for gain and low noise.
Is there any merit in a magnet sandwich - where a contraption is contrived so that the strings are between, but not touching, two magnets that are trying to push apart because it’s S pole against S pole? Or is that just silly?
Maybe there is even an application for something like ijustwannastrat’s vibrating sustainer idea?
John, after the "current amp" thing failed to pass signal I ended up just plugging the thing directly into my Bass V-Amp's instrument input. Had to crank it way up to get much of anything, and the noise was completely unacceptable.
I did get an inverting buffer to work last night, at least to the point where it passes and inverts DC. I was interrupted before I could take it any further, though.
Interesting...it reminds me a little of the idea behind Lace Pickups "Alumitones" a plate of aluminum and magnets, effectively a single turn coil with a transformer under it.
Good work in following through with actually trying it out.
I did attempt something like this with sustainer ideas years ago, not sure that I every really reported on it (like many of those things) and most thing sustainers are applicable in reverse as pickups.
I made a small coil (around a steel rivet as I recall) and sent a signal from an amplifier through it and so a magnetic alternating signal through the string, just behind the bridge saddle. Just in from of the bridge saddle I mounted two string but tiny neodymium magnets N & S. The idea as that the string being alternately magnetized it would be attracted to one and repelled by the other and so produce sustain. The neck pickup needed to be used to avoid 'picking up' the magnetic signal pushed through the bridge.
I did a lot of these kinds of "off the wall" experiments, very naively I suspect, in an effort to create a sustainer that would be built into a bridge perhaps and other aspects, like a hex system that would have a more even response...and to explore alternatives and ideas.
It failed in most respects, but as I say very DIY and naive, but it did have an 'effect'. I didn't take it any further really, it was just one of the many tangents at the time.
One wonders if such an arrangement wouldn't work as a pickup perhaps though.
The sound clip is interesting, but I feel that perhaps there is a bit of a dead end in this kind of thing perhaps...a lot of gain required and potentially noise for nothing "outstanding" in results...certainly not "the best acoustic sound" ever heard. also not the most practical of schemes.
I wonder what other kinds of "pickups" could be devised though.
Well done on following through on testing the concept out...pete
Mr D.I.Y. Sustainer ;-) [/IMG]New Project...'jazz strat' ... Seagull project and mini PA amplification