Music Man RD50 Mod Schematics, please!
Moderators: pompeiisneaks, Colossal
Music Man RD50 Mod Schematics, please!
Morning, I have a MMRD50 that I would like to mod the limiter channel on. I have seen some old threads that discuss this type of mod and indicate schematics are attached but have not been able to view any of these. BobW and Jooshtin to drop a couple of names. Could some one please direct me to the schematics or attach them to a pm? It will be greatly appreciated!!
Re: Music Man RD50 Mod Schematics, please!
My Daughter Build Stone Henge
Need help understanding MM RD50 Mod schematic!!
Thanks for the link! After looking at the schematic and reading BobW's description of the mods I have some questions that I hope someone can answer. I have pmed BobW and emailed Jooshin with no response, (guess they may have moved on). BobW's description of the mods from another post on another forum:
"In general, changed the V1a and b stages per the *umble OD stages.
In Particular:
1. disconnected the cathode grounds and ground leads from C10,R12 at V1-8.
2. Added a 5uf and a 1.8k at V1-8 and connected the grounds to the C10,R12,ground node.
3. replaced plate resistors R9 (470k) with a 180k, and R11 (4.7M) with a 150k.
4. replaced R10 with a wire jumper.
5. removed grin wire at V1-7 and added a 150k series grid resistor.
Initially also added a 470pF across the Clean Vol pot, and a 1000pF across the Limiter Vol Pot to smmoth the harshness at all vol levels in either Clean or Limiter mode."
I'm not quite sure which *umble stage he is refering to. Second comparing the schematic to the description I don't understand "disconnected the cathode grounds and ground leads from C10,R12" unless he is talking about connecting the ground side of C10 and R12 to the newly installed 5uf and 1.8k on the cathod of V1-8 and then running them to ground. Also R12 value has been change to 2.7k. I think I follow BobW's other changes. Regarding Joohsin's changes to C33, C34 R61 and C35 what is the purpose of those changes? Help will be greatly appreciated. I attached the link to the modded schematic.
https://tubeamparchive.com/viewtopic.ph ... t=musicman
"In general, changed the V1a and b stages per the *umble OD stages.
In Particular:
1. disconnected the cathode grounds and ground leads from C10,R12 at V1-8.
2. Added a 5uf and a 1.8k at V1-8 and connected the grounds to the C10,R12,ground node.
3. replaced plate resistors R9 (470k) with a 180k, and R11 (4.7M) with a 150k.
4. replaced R10 with a wire jumper.
5. removed grin wire at V1-7 and added a 150k series grid resistor.
Initially also added a 470pF across the Clean Vol pot, and a 1000pF across the Limiter Vol Pot to smmoth the harshness at all vol levels in either Clean or Limiter mode."
I'm not quite sure which *umble stage he is refering to. Second comparing the schematic to the description I don't understand "disconnected the cathode grounds and ground leads from C10,R12" unless he is talking about connecting the ground side of C10 and R12 to the newly installed 5uf and 1.8k on the cathod of V1-8 and then running them to ground. Also R12 value has been change to 2.7k. I think I follow BobW's other changes. Regarding Joohsin's changes to C33, C34 R61 and C35 what is the purpose of those changes? Help will be greatly appreciated. I attached the link to the modded schematic.
https://tubeamparchive.com/viewtopic.ph ... t=musicman