Can someone explain for the sake of learning? :)

[trip]

Hi everyone. As far as I'm aware most push pull amps running a quad can be halved in power by removing two tubes and compensating for the resistance by halving as well. I'm running this currently on an AT-100 and a JSX and have been pleased. For the below, can they all be run at half power as well because they are push pull, or if not, can you point to what would be the differentiator that doesn't make it possible or safe?

At-100 B52
BLue voodoo 120 crate
Peavey:
Jsx, 3120, 5150, triumph

I know the 3120 and jsx are close designs and all of these operate relatively the same but how would I know when it would not be safe to half?

Thanks!

[Enzo]

It isn't a matter of safe. It is a matter of will it work. Some Peavey amps wire the tube heaters in series, so you cannot pull any tube or the amp goes silent. None of the ones on your list are like that however.

As far as I know the B52 is wired utterly conventionally, so any of those can do this.

Remember half power is not half volume, volume reduces only a small amount.

[nosaj]

It isn't a matter of safe. It is a matter of will it work. Some Peavey amps wire the tube heaters in series, so you cannot pull any tube or the amp goes silent. None of the ones on your list are like that however.

As far as I know the B52 is wired utterly conventionally, so any of those can do this.

Remember half power is not half volume, volume reduces only a small amount.

Didn't look like it was mentioned but when you half your output tubes you need to change the load the other output tubes see.
https://www.premierguitar.com/articl...o-reduce-power

nosaj

[Enzo]

I thought he was referring to that in his opening statement by "resistance".

[nosaj]

I thought he was referring to that in his opening statement by "resistance".

He was guess my eyes are still glazed over

[g1]

Also, the common layout we are familiar with is almost universal, but not quite.
We are used to seeing an arrangement push-push-pull-pull for example, from left to right. So commonly we pull the inner or outer pair.
But there are rare examples of push-pull-push-pull layout, where you would have to remove the 2 left or the 2 right power tubes.
Best to check the layout on oddball or unfamiliar amps.