Reverb Amp

As mentioned earlier, the reverb amp has a distinct mains frequency hum when either or both of the reverb tabs are on. Further investigation reveals this is from the amplifier itself, rather than any of the associated wiring, reverb tank or the controls.

This will either be a bad valve (tube), or old and faulty capacitors. The electrolytic capacitors are most likely, given they are nearly 45 years old and well past their expected lifespan.

I'll be replacing these shortly, and also replacing the caps in the main amplifier as well.

While the main amp is out for capacitor replacement, it should be possible to fix the faulty vibrato as well - probably a failed resistor.