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RMC - Poly-Drive X  [schematic]

Posted: 27 May 2014, 08:22
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

Re: Poly-Drive X by RMC -schematic

Posted: 30 May 2014, 09:21
by apollomusicservice
more guts

Re: Poly-Drive X by RMC -schematic

Posted: 04 Jun 2014, 16:45
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...

Re: Poly-Drive X by RMC -schematic

Posted: 10 Oct 2015, 03:31
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:

Re: Poly-Drive X by RMC -schematic

Posted: 13 Oct 2015, 17:01
by Dirk_Hendrik
Thanks fot the big job done! I'm still puzzled by IC1B though.

Re: Poly-Drive X by RMC -schematic

Posted: 14 Oct 2015, 18:55
by lolbou
And where does U+ come from?

Re: Poly-Drive X by RMC -schematic

Posted: 15 Oct 2015, 14:29
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.

Re: Poly-Drive X by RMC -schematic

Posted: 18 Oct 2015, 01:24
by coldcraft
guys, its called a servo.

Re: Poly-Drive X by RMC -schematic

Posted: 18 Oct 2015, 15:37
by Dirk_Hendrik
Yes, a-DC servo. Continue on the why?

Re: Poly-Drive X by RMC -schematic

Posted: 18 Oct 2015, 19:58
by coldcraft
I doubt there's a strong reason why. probably just because they could.

Re: RMC - Poly-Drive X

Posted: 07 Feb 2018, 10:45
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.