In article . com,
dah wrote:

Thanks for the advice. I couldn't access a computer this morning and
ended up getting a Maplins 200VA transformer. It is nice and quiet in
operation. When fully powered up there is a moderately loud hum from
the speakers which I think is due to the big electrolytic filter cap
and coupling caps. caps. The values of these a
big filter cap consists of 4 caps: 1x 30uF, and 3x 20uF, but rated at
525V.
coupling caps are 2x 0.05uF and 2x 1uF, all at 400V
(transformer also uses 2x 0.02uF at 1000V).
Any suggestions on a UK source for these?

Can you say why you have concluded that all these caps are responsible for
the hum, and thus conclude that all need replacing?

Have you tried using the unit with its inputs shorted? Or checking the
earthing arrangements?

If you have not already done so - it may be worth your while to remove the
caps and check their values before deciding which of them may need
replacing.

Slainte,

Jim

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