Buzz diminishing with raised volume?

[Garlando]

I'm looking for some suggestions in dealing with a new problem with my system. I recently added a new higher VA power transformer for my McCormack Micro line drive preamp. It has added a good amount of dynamics to the sound but also has caused an annoying buzz through the speakers (I'm guessing it is around 120 hz) which decreases when I turn the volume pots up. With the preamp disconnected there is no buzz. When I replace the new transformer with the original wall wart the buzz is still present. The no load voltage from both transformers is nearly identical at 24V. The rest of the system consists of Cambridge Audio cdp, EAD dac, Helder tk250 monoblock boards and Pi 4 DIY loudspeakers.
I'm thinking the clue to the problem may lie in the buzz going away at full volume (wiith no music playing).

Any ideas?

Thanks!

Garland Branch

 

[mjf]

hello.
perhaps you have a bad soldering point/ground connection on your volume pot.

 

[DF96]

Sounds like the buzz is on your ground. You may have wired the new transformer in a way which injects charging pulses into the ground.