Tube wearout when using one ch on power amp

[virtu]

Mates when i use only one ch on a stereo power amp do i have the same tube wear out on all tubes?
The unused ch will have less, the same, or not at all tube wear out?

 

[elvis]

The tubes always have bias current in them, so they will wear. If the amp is class A, they will wear just as fast as if you are using them. For class AB (push-pull), they will wear much more slowly.

If you are using one channel at a moderate level, the tubes will not wear much faster than the unused channel. If you push the channel pretty hard during use, you will wear those tubes faster.

As with auto tires, you should consider rotating channels for even tube wear and best tube life.

 

[virtu]

Thanks bro...
I thought that the unused ch has a minimal tube wearout....
...yeah... i always rotate the channels from time to time...to me is common sense...

 

[edgecrusher]

I just pulled the tubes from the unused side of my 2:100 so they don't wear at all. Is this bad? I've had it like that for a while, and everything is still working fine... (I do keep the volume and presence all the way off on that side)

 

[crane]

Depends. In Mesa stereo gear there's only one power tranny. If you pull out some tubes, the other ones will see their voltage increase, especially plate voltage.
So the question is : how much is the increase ? If voltages stay under max values, it's okay.
In theory, if plate voltage increased, bias current should be decreased. Mesa amps are bias pretty cold (except EL84 models) so it shouldn't cause any problems if voltages stay under the max specs.

 

[darrenw5094]

Is there anyway to raise the fixed bias on the Mesa 2:90? It runs a bit cold.

 

[elvis]

Change the bias resistor or get tubes that run hot at standard bias.

 

[darrenw5094]

Change the bias resistor or get tubes that run hot at standard bias.

Is changing the bias resistor a simple job or a tech job?