Hoffman Amplifiers Tube Amplifier Forum
Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: pbman1953 on September 14, 2026, 09:29:50 am
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Back to the Fender Super Twin for a sec. Even though I'm done with these the amps they had more attack/sensitivity before changing anything. Cap changes were made because it was humming badly and the new caps solved that. The cap kit I bought were very close values to the schematic. With conversation in the forum here's the changes that were suggested:
1- V1A- pin 6-100k resistor to a 68k
2- V1B -pin 3 -1500 resistor to a 680 ohm
3- V4B pin 1 from a 220k resistor to a 180k
Other real changes- new OT's so I could have outputs for 4 & 8 ohm. The first amp has a Mercury Magnetics OT and the second one has Heyboer. If you feel the OT's are the reason for the difference , enough said, otherwise I'm wondering if the preapp should go back to stock values.
I have 2 versions of this amp so I'll send both schematics . One is an older version and one is a version in between a non-reverb and a reverb version. Both are non-reverb