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Topics - willpirkle

Amplifier Discussion / New Gamma SS Amps
May 21, 2022, 12:49:42 PM
Ok - curiosity is getting the best of me; I know these new amps are built by Acoustic (now owned by Guitar Center), and they look super-cheapo, but I'm curious about the "100% Analog" circuitry, especially for the distortion channels. No luck finding schematics (yet?) and a quick US patent search turned up nothing. Anyone here got any technical info on these?


I've scored a JC-120H (head) and I have the '84 Schematic as it is called. It is only one page and I'm looking for the rest of it, including disassembly instructions, etc... is there more of the '84 schematic than just the one page? Like a more complete service manual?


Schematics and Layouts / Roland JC-40 Schematic
April 11, 2021, 05:32:10 PM
Anyone got the schematic for the new(er) JC-40 with 2x10" speakers? I am aware of the awesome JC-120 ultimate thread on this forum and also found the JC-50 schematics here as well. But now specifically seeking the JC-40.


I have heard that instructions for the XPR to XPRa mods are out there...somewhere... and that the mods are extensive.

TIA if you can hook me up

- Will
Schematics and Layouts / Scholz UDG Schematic
June 29, 2020, 09:02:42 PM
Has anyone traced out the Ultimatum Distortion Generator?

Schematics and Layouts / GK Indicator Footswitch
May 02, 2020, 11:08:07 AM
I haven't contacted GK yet, but thought I'd ask here first — looking for the schematic for this GK footswitch used on the 112SC, 212SC, 150GT, etc from ~1980. The PCB inside is marked 50033B. The unit I received was DOA and someone disconnected the leads to the B channel switch at some point. I have a 112SC to test with.
Well technically not a solid state guitar amp schematic, I figured I would try here to track down schematics by the Studio Supply Company. These two cards came from a distribution amplifier out of a concert hall built in 1974. I believe the distribution amplifier fed individual offices in the bottom of the concert hall. I am trying to track down the schematic for what appears to be a multi band graphic EQ, all discrete which is in the second image. The first image is the backside of the only card that actually shows the logo of the company. Any help would be appreciated as always. Thanks.
Amplifier Discussion / Joël Huser amp module
January 13, 2020, 07:42:01 PM
This popped up on my LinkedIn feed, thought you might like it. MOSFET power amp section, claims 242W into 4 ohms. No connectors, leads solder directly to traces. I have not heard it, nor tried it, nor bought it. At the bottom of the linked page is a google drive link with the schematic and PCB layout info. Purely FYI.

Schematics and Layouts / GK 210G Reverb Tank
September 23, 2019, 04:31:11 PM
I need to replace a missing reverb tank for a 1978 GK 210G combo amp. The only think GK can tell me is that it is a Type 4 Accutronics and the schematic does not actually show or detail the reverb tank; does anyone know the part number or the specs (in/out impedance) for the proper unit for this amp?

Thanks in advance!