ripple noise...in PAiA Fatperson

[Paul Perry]

At 04:49 PM 10/07/98 +0200, Johan Persson  wrote:
>Thanks for all the answers on the audio OP amps! There's still something
>about my Fatman that bothers me, though...
>There is a terrible 50Hz  noise on the audio output due to the
>transformer I built into the box. I've tried to screen it etc, but 

before you conclude it is magnetically radiated hum, try removing the 
transformer physically and run the transformer output to the box by 5 feet
or so of heavy guage wire.. if it STILL hums, as I think it will, then there
is a 
power supply problem.. PAiA have a very competent person answering tech probs,
you could do worse than ask them by phone.

paul perry melbourne australia
...oh, just saw you are in .se!
do you have an oscilloscope?
because you could look at the power rail and see if there was ac there, and
if so 
what shape, which would be a good clue.
Could also be an earthing problem, like a bad connection to aluminium.
good luck and lets know how you get on.