KT88 SE

[andrew_whitham]

SO now I have a buzz if I plug in a source - worse if its musical fidelity vs rotel (?!?) but annoying otherwise. Not to audible if the volume is at natural listening levels but I don't quite follow how, if I unplug the source it's as quiet as a library on a wet sunday afternoon

Andy

 

[nubskillz]

Ground loop?

 

[andrew_whitham]

So FINALLY got bothered enough to investigate! Had a moment of clarity and removed the LED's - problem gone no buzz at normal levels. Back to resistors :-/

Now why might it happen? presumably PSSR is goosed with a diode rather than a resistor?that's outside my knowledge.

Worth noting that I have not bypassed the cathode resistors (or the LED's)

So on to the next project. metal-work first...

Andy