Mark IIB RP-9C Preamp schematic anyone ???

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jazzyjoepass
Bottle Rocket
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Joined: Sat Sep 17, 2016 5:01 am

Mark IIB RP-9C Preamp schematic anyone ???

Post by jazzyjoepass » Wed Aug 30, 2017 7:23 pm

Anyone has the RP-2C schematic?
The ones of the Mk IIB schematic available online seems to be very different.
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1990 Vox AC30 Top Boost Reverb
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IronSean
Mark III
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Re: Mark IIB RP-9C Preamp schematic anyone ???

Post by IronSean » Fri Sep 01, 2017 2:46 pm

Do you mean the JP-2C, the John Petrucci signature re-release of the Mesa Mark IIC+? Because I can't find anything for RP-9C or RP-2C.

If so, the Mark IIB is a very different amp. Even the Mark IIC is quite different. The IIC+ schematic should roughly trace the EQ and gain paths of Channel 2 and 3 of the JP-2C, with the most obvious differences being the Volume control was deleted in favor of Push-Pull toggles between two levels, and most of the DEEP/SHIFT controls were deleted as well. Also, obviously, the JP-2C has that lead channel duplicated twice, a second GEQ, a different clean channel, Shred mode, Midi, and more as well.

There's no JP-2C schematic out there to my knowledge.
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Rob Lockwood
Mark II
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Re: Mark IIB RP-9C Preamp schematic anyone ???

Post by Rob Lockwood » Sun Mar 18, 2018 3:19 pm

Did you find anything out? I have a Mk llB with the RP-9C preamp board. I started looking at it to see if there was an easy way to get the treble shift function to work on the clean channel. That was because I could never seem to get the sound I like that I have heard other (earlier) llBs from mine on the clean mode and I assumed that was why as its the one obvious difference. That lead me to start trying to draw the schematic of my llB by tracing everything through on the board. Its early days and it will take me long time to complete as I am also using the amp, but as you say its clear already that there are a lot of differences between this amp and the schematic commonly found on the internet. The gain boost function is one thing - it seems to work in a completely different way. Clean on my amp is a very clean Fender twin ish sound with little or no break up. Other llBs seem to gt a really nice overdrive by cranking the clean volume with lots of nice upper mid hrmonics.

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