Leaving tube amp on standby issues

[Grooveman1961]

Here's the link to the whole thing.

Invalid Link Removed

 

[Grooveman1961]

Tubes wear when they conduct. When they operate closer to their rated output, they wear faster than half power or quarter etc etc.

Class A's wear out faster than class B, ab etc, because they are conducting at idle. Having an amp on, with little output, like the condition the OP had, puts the least wear on the tube overall. (Class A excepted)

That mesa is more class b than ab, (I have one). Leaving it on with standby on will not hurt it.

 

[Eight_Stringer]

FWIW, tubes in low power application and rated below the recommended maximum operating criteria will last as long as the vacuum holds out. In power stages the tube is vulnerable from abuse of specifications. Inside the maximum operating conditions they will last many years...still have the same tubes in my amp from 29 years ago ( 12UA7 12 AX7 4 by 6CA7 ) Lost a few from bias issues ( nuked control grid ). Socket flashover is a killer, over dissipation on the plate from high bias for class AB another though more rare.

Kind of have trouble with the term "wear out" for any power device. More of a concern is the application environment in my view....regards John