JTM 45 Clone buzz/hiss

[markammon1979]

Hi, I have finished building a JTM45 copy based on a metroamp schematic. I have tested the amp today. The sound is excellent and everything is working as it should apart from a loud buzzing that gets worse as the amps volume is increased. The buzz is there all the time even when nothing is plugged in to the inputs. I have checked over the circuit and voltages etc. and all seems well. Any ideas?

[markammon1979]

Also...

I just wanted to add that when the amp is run on half power (using a Variac) the buzz/hiss disapears.

[Jazz P Bass]

Volume potentiometer

Is there any Vdc on the top leg of the pot?
There should be none.
If there is the cap before it is leaking.
Does the buzz go away if you ground the input?
Can you post a schematic?

[markammon1979]

I checked through the amp again and realised that there were some grounding issues. Went back through the circuit and checked all the grounds and the problem is solved. Thanks for the help.

[Jazz P Bass]

Clone buzz

Glad to here that you got the issue resolved.
Happy New Year.