Hum Fix in some small tube amplifiers

[Hi-Fi-Mogul]

For non-power transformer tube amplifiers,
residual hum may remain after changing out old capacitors.

These amps may be called stringed tube heater ciruit amplifiers.
Motorola Minion's explanation and solution,
are posted with that topic's page link.

The solution has been to install an electrolytic capacitor as
replacement for the original value capacitor in the B minus
to amplifier chassis location.

https://classichificare.com/viewtopic.p ... f&start=10