Re: tube choice for Leslies (chinese or russian)

[bpb@bpbsn.cca.rockwell.com (Brad Baker)]

In addition to some other stuff, Al Goff writes:

  > A Chinese 6550 tube in any label should NEVER be used in a Leslie.
  > Although they are inexpensive, they are the WORST choice.  They
  > are gassy, poorly constructed and do not stand up to the vibration
  > from the woofer and rotor.  After testing European and other
  > tubes, I settled on a solidly-made Russian (not-SOVTEK) tube
  > manufactured by Svetlana, the main Russian-military supplier of
  > tubes.  I have them made to our drive and audio specifications,
  > specially tested and privately labelled with the gold "GOFF
  > Professional" logo specifically for use in Leslie's.

(more anecdotal evidence)
a guitar player friend bought bunches of tubes for his mesa boogie
amplifiers in various flavors of both chinese and russian brands. his
opinion was essentially the same as al's - the chinese tubes weren't
made as well and were to be avoided.

he showed me both versions of an output tube (i forget which), and the
chinese brand had thinner pin-to-electrode conductors, thinner mica
insulators and more manufacturing sputter inside the envelope. he also
claimed that they suffered from premature failures.

brad baker
bpb@cca.rockwell.com