1982 Acoustic GT-60

This is a fairly un-common amp, Acoustic is more well known for their 70’s era Solid-State bass amplifiers. This 1980’s Acoustic is basically a copy of a Mesa Boogie Mark series amp with separate channels for clean and drive. The construction of the amp is unique and made for a challenging restoration with its top mounted vintage PCB. The early Solid-State driven Reverb circuit is a precursor of the same style circuits Fender would eventually use in their Hot-Rod series. The poor man’s Mesa!

The amp was completely restored. The electrolytic cap can was replaced with a new USA made CE brand 40/40/40uf 525v type unit for the filter section. The rest of the filter/bias/bypass caps were replaced with Vishay/MOD brand electrolytics with upgraded voltage and temperature ratings. New 2 Watt Metal Oxide/3 Watt Cement power dropping resistors and screen grid resistors were installed for better reliability and lower noise floor.

The original tubes did not test good and were all replaced. V1 = JJ 12AX7MG, V2 = JJ 12AX7S, V3 = EHX12AT7, V4-V5 = JJ 6L6GC Matched Pair. These tubes were picked for best tone and reliability. The 6L6GC’s Fixed Bias was set to %52 Class AB Plate Dissipation with a B+ of 464VDC. The Handle and Chassis Side Rail were both undone/broken and were put back into place with the original and new hardware respectively. Amp now functions perfectly.