Hi there,
I'm working on an old Silvertone with two EL84's in push pull, sharing a single cathode bias resistor. When the output is increased to 3+ watts, 1KHz sine wave input, There is a big high frequency oscillation on the lower half of the wave-form. The oscillation stays there even if I swap the tubes. I've tried a known working phase inverter 12ax7 to rule that out. Any thoughts?
This is a Silvertone 73, I'll attach a schematic of the power section.
I'm working on an old Silvertone with two EL84's in push pull, sharing a single cathode bias resistor. When the output is increased to 3+ watts, 1KHz sine wave input, There is a big high frequency oscillation on the lower half of the wave-form. The oscillation stays there even if I swap the tubes. I've tried a known working phase inverter 12ax7 to rule that out. Any thoughts?
This is a Silvertone 73, I'll attach a schematic of the power section.
An externally hosted image should be here but it was not working when we last tested it.