"Arfa Daily" wrote in message
...
OK, so when I asked about the bias setting on the Lumleys, Keith suggested
that the owner should be running Svets in there, as did several others, so
I went looking for some sources and prices. Watford Valves have some "
Cryo - Treated " Svet 6550C's for a couple of quid more than the
'standard' types. See

http://www.watfordvalves.com/products.asp?id=10

This is a new one on me. Has anyone tried them ? Is there really any sound
or performance improvement from them ? Or have they maybe been cooled in a
big vat of the snake oil that everyone on here is so fond of talking about
?

Arfa


My guess is you'd be better spending the extra on upgrading circuit
components but I have never actually tried those cryogenically treated
valves. I'll try and find my notes but I remember changing psu diodes over
to the faster UF5408 & UF4007. The 6550 cathodes now stand on 1 ohm w/w for
metering, several other changes like reduced global f/b and changes to both
the driver and input boards but as I say I'll try and find my original
notes. That was all of 10 years ago...

Mike