In article , Dave Plowman (News)
scribeth thus
This time, a BBC AM8/16. Basically, a BBC modified Quad 405 to drive the
LS5/8. Has a crossover added to the input to the amps.

One of the two produces a pretty loud squawk on switching off. Not a fault
as such, as plenty early BBC ones in service did the same. But the BBC did
seem to find a cure. The pair I had were ok.

Sadly, the three circuits I've got for the crossover are all the same.

I've only got the one amp here, so can't just look for any differences.

I can post a link to the crossover circuit if it helps. It gets its power
from the + side of the Quad PS and regulates that down to 30 volts.


Are you saying that one channel squawks whist the other doesn't?.

If this was a problem overall with the 405 I bet QUAD would have done a
mod for it even in the balanced input splitter/driver board

Very much expect its a duff cap or caps somewhere well worth changing at
the age thats likely to be..
--
Tony Sayer