Recently my system has developed a very audible hiss in the right channel.
The hiss exists with all input devices, leading me to believe it is a
problem with the preamp, a Counterpoint SA-3000 hybrid. I'm wondering if a
tube is going. The amps are solid state Classe CAM-200 monoblocks driving
Theil 3.6 speakers.
Any thoughts?
Tim

First things first, to confirm that it is your preamp, select a source and
verify the hiss, then swap the interconnects going to the amps. If the hiss
switches to the other side, you've confirmed that the problem is not in the
power amp. Then you can swap the interconnects on the preamp inputs, just
to make sure it's not any of the source components. Assuming the problem
lies in the pream, tubes would be the most likely candidate. The 6DJ8s are
directly replaceable with 6922s and are fortunately, about the most commonly
used tubes around. Many current preamp manufacturers (Audible Illusions,
Melos, CAT, etc.) use selected Sovtek 6922s. Unselected, these can be
purchased matched from New Sensor (www.sovtek.com) for about $12 per tube.
There will no doubt be some following discussion about the various sonic
benefits of different brands of tubes.

"TimT" wrote in message
...
Recently my system has developed a very audible hiss in the right channel.
The hiss exists with all input devices, leading me to believe it is a
problem with the preamp, a Counterpoint SA-3000 hybrid. I'm wondering if a
tube is going. The amps are solid state Classe CAM-200 monoblocks driving
Theil 3.6 speakers.
Any thoughts?
Tim

Bruce Abrams wrote in message ...
Assuming the problem
lies in the pream, tubes would be the most likely candidate. The 6DJ8s are
directly replaceable with 6922s and are fortunately, about the most commonly
used tubes around.

Ah, I only wish that this were true. I have an unmodified Counterpoint
SA-3 and 6922s will bias into cutoff in that circuit. One of these
days I need to rebias it, but at this point all I can use is 6DJ8 (and
it's time for a new set).

(Yes, it's me. Amazing that you guys still argue about the same things
almost 20 years later. Some of the same people, too!)

Tom

[ Welcome back Tom! -- deb ]