Breezio
Well-known member
Dear all,
After the succesful rebuild of a B+ regulator (https://groupdiy.com/index.php?topic=71117.msg906020#msg906020) I am now facing a hum on the right channel of my AMC CVT3030 amp.
There is moderate 120Hz hum (see pic below) for which I cannot identify the source.
The hum is always present, is not affected by the volume level and the audio signal works fine.
The hum is present only when a signal cable from the preamp is connected to the right tube stage.
However, I cannot measure anything on the tube input (CN501) and switching L/R channels from the preamp does not change anything either (meaning that the hum is present as soon as a signal cable connects to the tube module)
Any suggestion?
Thanks again
Fabrizio
After the succesful rebuild of a B+ regulator (https://groupdiy.com/index.php?topic=71117.msg906020#msg906020) I am now facing a hum on the right channel of my AMC CVT3030 amp.
There is moderate 120Hz hum (see pic below) for which I cannot identify the source.
The hum is always present, is not affected by the volume level and the audio signal works fine.
The hum is present only when a signal cable from the preamp is connected to the right tube stage.
However, I cannot measure anything on the tube input (CN501) and switching L/R channels from the preamp does not change anything either (meaning that the hum is present as soon as a signal cable connects to the tube module)
Any suggestion?
Thanks again
Fabrizio