"Fleetie" wrote in message
...
Hi.

While I'm here, does anyone know the usual cause for a valve amp
constantly "rustling" out of one channel? Mine is doing it
intermittently and sometimes loudly, out of the left channel.
Is it likely to be a resistor burning up, or something about
the valves? Is it likely to be in the output stage valves or
cathode resistors, or...? It's starting to drive me nuts!

Is this the kind of symptom that tends to always have the same
cause?


Hello Martin.

The first thing I would suspect is the contact between the
socket pin grips and the valve pins on the input and driver
tubes, particularly if they are B9A type (miniature nine-pin)
Some (particuarly Chinese) valve bases have contacts that
open up, and don't contract again to grip the pin firmly.

If this is the cause, you can find the culprit by a little
"waggling" (these hi-tech solutions are often the best!)

Then, switch the amp off, pull out the valve, and clean the pins
with aerosol contact cleaner. Spray a little into the valve
base also.

Hope this helps.
Iain