Hoffman Amplifiers Tube Amplifier Forum
Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: davidb on March 03, 2022, 05:22:43 pm
-
Hello all,
I am new to the forum and new to amp modification, so I wanted to ask for some advice before I start on this project. I have been researching safety and tube amp function for a while, so I finally feel confident enough to give it a shot. Also I have been building and designing pedals for years, so I have a decent understanding of electrical schematics.
I've got this 90s Reverberocket that isn't quite doing it for me. Clean channel and reverb are great, but the gain channel is too mid-focused and has too high gain. I was thinking of doing the following mods:
- Add a bright cap to gain control
- Remove 1, maybe 2 cathode bypass caps after the tone stack
- Beef up all other cathode Bypass caps to 22uF or higher
- Remove C40 so the tone stack is always scooped. The schematic says C40 is in the circuit when the clean channel is on (I think), but my amp sounds exactly the opposite - much more midrangey even when clean.
Could you share your thoughts on if this is a good place to start out? I'd like to hear some feedback before I commit to it.
https://ampeg.com/support/files/Schematics/R%20Series/R-212Ra/27801HK_.pdf
Thank you so much! Excited to be learning something new!
David
-
I would start by confirming that C40 is being switched in and out as intended.
-
Thought I would sum up my findings in case another person wants to mod theirs. I replaced the C46 and C48 bypass caps with 47uF to give it more bottom end, and clipped the C47 bypass cap to reduce the gain. I also replaced C49 with a 220pF cap to reduce the high end roll off on the overdrive channel. Pretty happy with it, but may keep tweaking.