In article .com,
spwyatt wrote:
The main problem is that both amps exhibit a low level but perfectly
audiable mains hum - even with their gains right down and nothing
plugged into the (XLR) inputs. Am I right in thinking it's reasonably
easy to fix by changing some capacitors? Any help greatly appreciated!!

Failed electrolytics are a common fault on these. Remember they could be
near 30 years old. I'm sure if you Google you'll find details on the best
replacement makes, etc.

--
*Most people have more than the average number of legs*

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