Weird MC2000 issue

[Ossidian]

Originally Posted by Cohibaman

Did you ever find out what the problem was?

I would like to know as well, since I bought an MC2000 last month. Plays fine.

[McInosh]

So how's this for a late reply :-)

Burnt right channel output stage cathode resistors, and a couple shot tubes with open filaments.

Replaced em all. GL KT-88's and NOS 60's Mullards for the AX7's and AT7's

[Formerly YB-2]

Not unusual for a tube to take out various components when it blows. All depends on the amp design and method by which the tube fails (for instance, a short will allow max current draw, etc.). I usually try to change the power tubes ~2000hr. However, there is no guarantee that is soon enough. Welcome the wacky, wonderful world of tubes.

[jdandy]

Thankfully, McIntosh finally solved the issue of damaged internal parts in the circuit when a tube power fails. They developed the McIntosh Sentry Monitor circuit for tubes and made it available in the MC275 Mk IV and the MC2301 tube amplifiers. When a power tube fails in either of these two amplifiers the AC power is immediately interrupted thus protecting the internal parts. It is a valuable upgrade to both amplifier designs and reduces tube failure paranoia.