Switching between channels using different wattage for each

[Jiveman]

Probably a silly question, but it just occurred to me that I never saw this anywhere stated (read the manual long time ago, but I don't remember now), so I guess here it goes....

Is it "advisable" to set one channel to, say 45 watts, and another to, say 90 watts, and then switch between them (via footswitch or whatever)? Yes, yes, I know that if this wasn't possible or "safe enough" it wouldn't exist as an option and there would be a global wattage switch instead of per channel, but that doesn't quite get to the heart of what I'm asking. I'm basically curious if it's MAYBE not "advisable" to use mismatched wattage settings in different channels, as this engages different sets of tubes, on and off. Given that sometimes I switch channels quite frequently in a song, back and forth, I wondered if this is at all problematic for the tubes.

 

[Authorized Boogie]

Probably a silly question, but it just occurred to me that I never saw this anywhere stated (read the manual long time ago, but I don't remember now), so I guess here it goes....

Is it "advisable" to set one channel to, say 45 watts, and another to, say 90 watts, and then switch between them (via footswitch or whatever)? Yes, yes, I know that if this wasn't possible or "safe enough" it wouldn't exist as an option and there would be a global wattage switch instead of per channel, but that doesn't quite get to the heart of what I'm asking. I'm basically curious if it's MAYBE not "advisable" to use mismatched wattage settings in different channels, as this engages different sets of tubes, on and off. Given that sometimes I switch channels quite frequently in a song, back and forth, I wondered if this is at all problematic for the tubes.

The amp designed to operate at different wattage settings in different channels. Thanks!

 

[Jiveman]

Cool, I figured that would be the case, but it's always good to hear official word on these kinds of things! Awesome! Thanks!

 

[jb's 52]

One caveat,

If you go from 10W to a 45W or a 90W channel, you'll hear a audible pop.

 

[Altair-IV]

If you go from 10W to a 45W or a 90W channel, you'll hear a audible pop.

That's correct.

When one switches power level, the amp is switching bias on the tubes. Anytime you switch bias or other property of the circuit, the amp jumps to a new "Q" point which represents the "no-signal" conditions of voltage and current flow. When the amp makes such a change; one gets a transient spike in voltage that the speakers reproduce as a pop.

One can think of the 3 power settings, or 3 bias settings as being analogous to the "gears" on a car.

The car is meant to operate properly in any of the gears, and to go between gears as a normal part of being driven.

Also, when one switches gears, one gets a change in engine pitch as well as a bit of a "lurch"; which are analogous to the "pop".

Altair-IV

 

[Jiveman]

Good analogy, Altair-IV! Makes a lot of sense!

I was aware of the pop going between 10 and 45/90, and it's very loud sometimes, so I generally avoid that no matter what. More realistic scenario for me would be either all same wattage for all channels, or a mix between 45 and 90. In latter case, there is not much of a pop that I notice, but that's where I started wondering whether it's problematic or not. Good to know it's perfectly OK to do that!