2:90 poweramp channels and tubes?

[nexus]

Hi,

if I use only one channel at the time i.e. channel A do I need to keep the tubes on the channel B side too? At the moment I'm using only one channel but does the signal go through all of the tubes?

The idea was to save money by using only the tubes that are needed or does it have any affect on the channel B tubes if I'm using only channel A?

Cheers

 

[ylo]

The 2:90 has two inputs and two outputs, ergo, it is TWO separate amps. However, some of the preamp tubes probably use side A for channel 1 and side B for channel 2. You could perhaps remove four of the power amplification tubes (the 6L6 tubes). I don't see any surprises on the schematic, but if I were you I would talk to Mesa before doing this. Of course you have to remove the correct four tubes.

 

[Boogiebabies]

NOOOOOO !!!!!

The output transformer needs to see a load from the power tubes.
You will blow the whole bank if you do this. It can possible take both transformers. Just leaving it on standby will keep the heaters glowing.
This does not wear the tubes out at all.

 

[oxtone]

For many years now I've used just two 6L6's per side on my Simul 2:90, and I've not had any problems whatsoever.

I use the lower left, and upper right sockets per side, loaded with Groove Tubes 6L6GE's. The amp still sounds HUGE with two power tubes per side.

I had met a guy who did that, who told me the amp would sound more "Class A", so I tried it. I loved the sound, so I stuck with it.

And with the Groove Tubes 6L6GE's, I get bigger bottom end, and sweeter mids and highs.