Please note that this schematic seems to have some errors
1) The plate resistor for the reverb driver was 2.2k on the amp.
2) Missing some filter caps. Compare with a same vintage Ampeg R12R, it is missing 20uF filter caps on nodes S and T. I also found that hum dropped when I added another filter cap to node U. A
Please note that this schematic seems to have some errors
1) The plate resistor for the reverb driver was 2.2k on the amp.
2) Missing some filter caps. Compare with a same vintage Ampeg R12R, it is missing 20uF filter caps on nodes S and T. I also found that hum dropped when I added another filter cap to node U. A