Unorthodox Approach To Guitar Electronics

[dominix]

I've been successfull in the past with some basic experiments with passive guitar circuits, and recently have had success winding a pickup (sounds sorta lame, but better than I thought for a first attempt). Anyway I've been thinking or going fretless and that started me down a path of wondering about good ways to boost sustain.

I've got quite a few ideas on the subject (definately going to wind a hex pickup), but before I delve too much into that I've a few questions for anybody reading. I'd like to keep the circuitry passive though I recognize that I might have to abandom that in favour of a dc voltage source. Now if I were to coat my fretboard with something that will conduct and/or I charge my strings with a slight voltage would this be an effecient way of getting more induced current in my circuit? What kind of effect would I get out of the capacitive action created by the seperation of the string behind and in front of my fretting possition should I expect to get? if I use a long coil wound along the entire length of the neck (mounted wherever, right now I'm considering just gouging out a channel into the neck underneath the fingerboard. Anybody have any insights that will save me a little brain work in this? The final goal would be to have a strong magnet that actually pulls on the string significantly (fretless remember, no intonation problems, I'll just adjust) where I can use the current generated from the inductance attached to that part of the circuit to charge a big capacitor (guitar string or just a normal cap) which will be used as a dc voltage source to drive an oscillation at the field attached to the part of the string behind my fretting hand (the part attached to the nut or even a 'dummy' section of string that never gets fretted and is only used to resonate, like a drone on a sitar). Now when I fret (play) a note that will make contact with the capacitor/string providing a path to ground that would cancel out the effect except for that the path I provide has a comparatively high resistance to the path through the circuit if I use the correct values of capacitance, resistance, voltage and inductance is that correct? Sorry there's more asked here than telling.

Oh and one last thing I should point out is that even though this brain storm started out as a sustainer idea for a fretless at this point I'm primarily interested in the concept and how that could be usefull for say a guitar controller that actually plays through a synth for example.

*whew* I hope somebody takes interested in this....

[lovekraft]

Once you touch a conductive string to a conductive fingerboard, the capacitance is going to drop to near zero. Theoretically, you could use the strings and the fretboard as a resistive controller - google ribbon controller for some ideas along that line.

[dominix]

Once you touch a conductive string to a conductive fingerboard, the capacitance is going to drop to near zero. Theoretically, you could use the strings and the fretboard as a resistive controller - google ribbon controller for some ideas along that line.

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ABSOLUTELY, thanks for the info on the capacitance, I can drop that idea then (I'm NOT going to don a pair of gloves... heh) *googles ribbon controller*

[lovekraft]

OK, here's a thought - inlay conductive carbon strips into the surface of the fingerboard, one under each string, and wire a terminal to each end of the strip. You now have a giant potentiometer, with the string acting as the wiper terminal. The only problem is going to be calibrating the response curve (the taper of the "pot", if you will) to get the correct frequency from whatever sound source you're using at or around the correct position. Sounds like a lot of work, but definitely doable, given sufficient resources and effort.

[dominix]

Thanks once again, Lovekraft... Now that I've got back from vacation I can start to try some of these ideas out. Should be exciting. =)

[dominix]

OK. I've done a little more research and am now thinking more about what I could do at the circuit level of the fretless. Does anybody know how much current I could realistically generate in a strong inductor taken across the guitar strings? Or could point me in a direction that I might start researching it. It's such an impractical use of an inductor I've been having problems finding good sources for information.

[lovekraft]

Does anybody know how much current I could realistically generate in a strong inductor taken across the guitar strings?

I'm not sure what you mean - could you explain your plans a bit further?

[dominix]

For example, say I wanted to run a low frequency oscillator in one of the pickups to boost some lows, or add crystal to resonate high frequencies and step up the inductance (if I know what I'm talking about, and I'm not sure I do...). The best approach would be to use a battery, but would it be possible to attach a strong inductor somewhere to pickup enough current off the strings to power either of these elements or maybe even something more basic like an active eq. I'm really fond of the idea of adding some "active" circuitry driven by the guitar itself, or at least to find out how short of the mark the idea is.

[lovekraft]

OK, if I understand the question correctly, no, your pickups will not generate enough current to power any kind of circuit. They barely make enough current to induce a signal in a high impedance input without loading being a serious problem. Does that help?

[dominix]

It helps alot! Saves me alot of work, I'd've probably been at this question for weeks otherwise, so thank you. =)