Have a home made amp in the workshop which is used a great deal - I tend
to listen to the radio all the time I'm in there. And of course doubles as
a test amp for anything needed. My diagrams for it are dated 1997, and
it's worked just fine since I built it.

Until last Friday. Had to turn the volume well up to hear anything.

It has balanced inputs, and the unbalanced outputs appear beside the
workbench as phonos, and are normally jumpered across to the pre-amp
inputs. The speaker outputs and inputs also appear there.

A quick fiddle showed it was the balanced to unbalanced side which had
died. Both channels. The PS for these is independant of the power amp one,
+/- 15v regulated, and its LEDs showed it working.

For some reason shrouded in the mists of time, I'd used SSM 2017 rather
than the more usual SSM 2143, etc. Perhaps to give a bit more gain. Or
perhaps just because I had loads.

Both had blown. Replaced and all is now fine.

The pre-amp shares the same PS.

Only odd thing was the severe lightening we had on Thursday - as
spectacular as I've seen in London. But it was switched off then, although
still connected to ground (and neutral)

The balanced inputs would still have been connected to my distribution
system - but everything else on that is fine. And the cabling for that is
all internal.

Any guesses?

--
*I don't suffer from insanity, I enjoy every minute of it *

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