RMC - Poly-Drive X  [schematic]

Pickups, wiring schemes, switch techniques and onboard active electronics for guitars and basses
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apollomusicservice
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Post by apollomusicservice »

A few days ago in my service popped in LGXT Godin guitar for repair.
The guys from the company RMC did not want to give me schematic for Poly Drive X preamp,
so I had to draw it. This is my drawing of the preamp for all those who need it as a reference or personal use.
More photos and information from my workshops on my Facebook page. https://www.facebook.com/pages/Apollo-M ... 5494552791
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Poly-Drive X by RMC.png
Poly-Drive X preamp.jpg

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apollomusicservice
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Post by apollomusicservice »

more guts
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Poly Drive X.jpg

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patafix
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Post by patafix »

They made a revision in 2011. I ordered one. I can offer shots since I haven't installed it in my guitar yet.

There are a couple of mods from what I see, the most noticeable is the presence of two additional transistors and the swap of a tone cap from 33n to 47n...
Patafix... so sticky

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n9voc
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Post by n9voc »

Thank you so much for posting this. I needed to replace the battery connection - and your pictures helped assure me that it was going properly polarized! :applause:

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Dirk_Hendrik
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Post by Dirk_Hendrik »

Thanks fot the big job done! I'm still puzzled by IC1B though.
Sorry. Plain out of planes.

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lolbou
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Post by lolbou »

And where does U+ come from?
- Are you a mod or a rocker?
- Uh, no, I'm a mocker.

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Dirk_Hendrik
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Post by Dirk_Hendrik »

One would expect U+ to be some kind of biasing voltage for the 6 FET's. For that reason it's rather odd to see that the opamp that seems to source this U+ is derived through an integrating opamp from the summing bus of those FET's.

I am sure more the brilliant minds see the logic of the setup straight away.
Sorry. Plain out of planes.

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coldcraft
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Post by coldcraft »

guys, its called a servo.
Black Dynamite wrote:you need to shut the fuck up when grown folks is talkin.

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Post by Dirk_Hendrik »

Yes, a-DC servo. Continue on the why?
Sorry. Plain out of planes.

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coldcraft
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Post by coldcraft »

I doubt there's a strong reason why. probably just because they could.
Black Dynamite wrote:you need to shut the fuck up when grown folks is talkin.

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Post by papasteack »

The individual input circuit/eq for each piezo is really interesting. If someone can simulate it, i would be very curious to see curves of the different individual input stages...
Graphtech piezo doesn't do this kind of induvidual tweak with their simple summing board.

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