IR: Gibson RD Artist Moog pre-amp circuit

Pickups, wiring schemes, switch techniques and onboard active electronics for guitars

IR: Gibson RD Artist Moog pre-amp circuit

Postby Prostheta » 01 Nov 2012, 15:15

Hi everyone. Haven't been around for a while but that's another story entirely. :mrgreen:

I'm building a reproduction of a '77 Gibson RD Artist (actually, more like a '79 but hey) along with the massive Moog designed pre-amp in the rear. Information available here:
http://www.flyguitars.com/gibson/bass/R ... chinfo.php

What is particularly interesting is this.
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Now that's one big sockcooker of a circuit for an instrument.

Has anybody come across this before? I can quite easily do a trace from the schematic:
Image

...however I would be very interested in discussing the circuit with anybody that has experience or those that have opinions on where the circuit could be improved, if at all. I think the bass original came with two single coils and the general commentary is that the circuit was exceptionally noisy when pushed hard. I presume shielding would be the first thing to look at on this of course.

I welcome input. :hug:
"People demand freedom of speech as a compensation for the freedom of thought which they seldom use" - Søren Kierkegaard

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Chrisfromiowa (27 Jun 2018, 20:44)
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Re: IR: Gibson RD Artist Moog pre-amp circuit

Postby Dirk_Hendrik » 01 Nov 2012, 18:39

Personally I tend to have problems with "Moog designed" and "where the circuit could be improved" in one post. However the "if at all" softens that ;)

I've got to do a search because I'm fairly sure I've seen these electronics in a very different form on a (bloody heavy) Les Paul Artist for which I repaired the electronics. Did not need a schem but took pics since one does not see these on a daily basis.

Search....

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Sorry. Plain out of planes.

http://www.dirk-hendrik.com

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Prostheta (05 Nov 2012, 18:02)
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Re: IR: Gibson RD Artist Moog pre-amp circuit

Postby Prostheta » 01 Nov 2012, 19:16

The layout style is very familiar at the very least!

These circuits all look like they were Gibson's foray into the world of waveform shaping and active electronics. Not a bad thing, and in my opinion the RD Artist was the best bass they made. I am teaching guitar building through a parallel build next week so I took the opportunity to concentrate this onto the RD Artist. All that really remains is to recreate the electronics which shouldn't be difficult, if somewhat tedious due to the quality of available reference materials. I bet this would sound fantastic with modern quality components coupled with immense amounts of shielding. Just got to nail what those pickups were and the rest is just hacking away at the problem....

My only potential concern is the gain of the circuit if I combined it with modern pickups. An Aria Pro II instrument I did some work on recently used super-low output pickups with the pre-amp picking up the slack in volume, and the 6kΩ DCR of the Gibson mk5 pickups make me wonder....that's pretty low even for single coil pups. Knowing this from logical inference could be useful in modifying the pre-amp for variable gain to help match it to the pickups used. I'm pretty crap at analogue electronics now having been seduced by the general copy-paste society we now live in. (pffp)
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