1972 Fender Pro Reverb

Don’t be fooled by appearences - this is a Silver-Panel amp pretending to be a Blackface era Fender. The Pro Reverb is often called one of Fender’s best designs, being a 40 watt amp with a 2x12” cab, a 5U4GB tube rectifier, and the classic BF/SF clean tone with Reverb and Tremolo. This particular one came in with a non-functioning reverb, crackly pots, and hum. It was in need of a full cap job/restoration.

This one was worked on many times throughout the past by others and had many mods done to it including new speakers, mods to Black-Panel the amp, a Black-Panel faceplate (This is a Silver-Panel amp), a new Mercury Magnetics output transformer, etc. All caps were replaced with upgraded voltage and temperature rated MOD brand electrolytic’s. New 2 Watt Metal Oxide power dropping resistors were installed for better reliability and lower noise floor. The Black-Panel mods were kept as per the customer’s request. The original Accutronics reverb tank was shot (internal short in output transducer) and was replaced with a MOD brand 4AB3C1B tank. A .01 630v Mallory film cap was used to mod the Trem circuit to stop it from ticking.

The amp needed a full set of tubes - V1 = JJ 12AX7S, V2 = JJ 12AX7MG, V3 = EHX12AT7, V4 = JJ 12DW7, V5 = SOVTEK 12AX7WA, V6 = TUNGSOL 12AT7, V7-V8 = TAD 6L6WGC-STR Matched Pair. I put a JJ 12DW7 in V4 to help with mechanical feedback that was happening with the particular combo of repro cab, reverb tank (3 different tanks were tried for least amount of feedback) and Celestion Hellatone speakers. The 12DW7 is a dual triode with one triode having the spec of a 12AX7 and the other having the spec of the lower gain 12AU7 - this helps the reverb control have a larger usable range and cuts down on noise/oscillation.

The TAD 6L6WGC’s - which are some of the better sounding 6L6’s available right now, being repro’s of the small bottle clear-top GE from the 60’s - had their Fixed Bias set to a period correct %60 Class AB Plate Dissipation with a B+ of approx 440 VDC. All pots were sprayed out and all hardware was tightened.