[Scott Dorsey]

Gareth Magennis wrote:

I don't hve the unit here any more, the customer is intending shipping it to
the manufacturer in the States, after videoing the evidence on his iphone.
He has been in contact with the designer of this unit, who has been vey keen
to help, so I expect a good result, apart from the shipping bills!

You may well be seeing an engineering problem here, yes.

By the way, the transformer actually has no screening at all, Scott. There
is a metal partition running from front to back of the 1U case separating
the transformer and PSU from the cards though.

What about the input transformers? The way this stuff normally happens is
that the power transformer radiates field and the input transformers pick it
up. It's cheaper and easier to shield the input transformers than the power
transformer and also gives you isolation from the power amp in the rack space
above.

I have seen transformerless input stages pick up magnetic fields also, due
mostly to bad PC board layout. That's a different issue really, though.
--scott

--
"C'est un Nagra. C'est suisse, et tres, tres precis."