In article ,
Archibald wrote:
It sounds like you have a magnetic field interfering with the
cartrige. Try sticking the end of the arm into a grounded empty baked
bean tin. Then if it diminishes the hum see what electrics have been
added lately.

Normally if that's the case simply moving the arm will alter the hum. It's
the same in both the workshop and living room, so it's not a local thing.

The SME arm is aluminium or an alloy thereof as far as I can recall,
not the best magnetic screen.

If the PSU is still suspect incidentally I would be tempted to try a
smooth DC supply and a couple of 15V Voltage converters. Not sure of
the switching frequency though, you may be swapping 50Hz for 20kHz :-)

Since there's no hum at all with the input to the pre-amp disconnected I'm
fairly sure the PS is ok.

--
*I couldn't repair your brakes, so I made your horn louder *

Dave Plowman London SW
To e-mail, change noise into sound.