Iain Churches wrote:
"Rob" wrote in message
...
Iain Churches wrote:
"Rob" wrote in message
...

FWIW the three bits of valve kit I have (Beard power, AI integrated and
EAR phono), and the one I had (Carmenta pre), are pretty quiet. The
Beard has a slight hum from the unit (transformers?), but less than some
SS amps I've had.
The Beard valve amps that I have seen perform well. They have fairly
small
mains transformers, which are bolted straight to the chassis. Setting
them
on rubber grommets (and also tightening the bolts that secure the
laminations)
gets rid of the transformer noise.

Thanks Iain - the transformers are tucked away and last time I looked they
weren't readily accessible, and I suspect they're a fair size given the
amp weighs about 35kg. And if my fettle causes a problem, they're a
problem to replace - £500 each springs to mind.

Rob. The Beard that I worked on (SP35 IIRC) had the
mains transformer mounted centre chassis under the rear cage.
Before removing it, check the tightness of the bolts through
the laminations. This might solve the problem completely.

If not, you will need to drill out the transformer mounting
holes to say M8 and then fit the grommets. Put a tab
washer top and bottom, and then ensure that the transformer
bell is grounded to chassis (a separate black wire may
be required with a solder tag at each end from one of the
lamination securing screws to the transformer fixing bolt -
clean off the varnish if required) Don't bolt the transformer
down too tight.

Best regards
Iain

Cheers Iain - it's a P100, a dual mono affair. The transformers are
under covers that flank the valves, and at my last under the lid peak I
couldn't work out how to get the covers off. But next time I'll set at
it with a new determination.

Rob