Quad - hum from hell

[Qstick333]

As mentioned in another thread, I am borrowing a Quad for a bit to see if it is my thing...

I hooked it up tonight with my tubeworks 50 watt stereo power amp and furman and noticed that with the volume above 3-4, there is a huge hum from hell.

It will go away when the amp is on standby. Reverb has no imapct. Guitar being hooked up has no impact. Volume has a huge impact...goes across all 4 channels.

Can someone steer me onto to where to look?

Thanks,

Zach

 

[disassembled]

Try turning the outputs to 100% and use the volume on your power amp to control volume.

There are 2 versions of the Quad (the older with the FU2 and the newer with the FU2A footswitch) and there was allegedly a fix on the newer versions of the quad for the hum. I have owned both versions and will say that the hum seems more apparent on the first version.

Maybe you have some more problems going on not related to the version of your quad: ie bad power, line noise, bad ground, bad tubes, bad cables, ground loop, etc.


Greg

 

[Qstick333]

At the risk of being scolded and feeling like a total moron...

I realized that I hadn;t flipped the ground lift switch and flipped and lifted the circuit and the hum is gone..

I feel