TRRI - pulling output tubes

[haledixon]

ive read about this being recommended to effectively somewhat lower the output on the twin reverb... has anyone here done this? if so, results? and exactly which tubes are the ones that should be pulled?

[1946dodge]

I have a Marshall 2555 that runs in either 50 or 100 watt mode. It does this, I believe by disabling two of the 4 output tubes.
It was designed that way. I would not try this on any amp that was not designed to do that, unless I clearly understood how the circuit worked.
You can't lower the volume? The twin has both a volume and master volume control, the volume one being essentially a preamp control and the master for the output tubes, I believe.
You can lower the preamp volume to clean up the sound or turn it up, and lower the master volume if you want to thicken it up.
I would ask a Fender rep for advice on this, or a reputable tech that deals with these amps before pulling anything.
JMHO
Ed

[mynameisjonas]

i think he's talking about the '65 reissue, which doesn't have a master volume.

i've heard about lots of people pulling 2 out of 4 output tubes in various different amps, but i don't know which two you should take out.

[haledixon]

yeah, it's the '65 reissue. yeah, the volume can be lower with the volume at 1.5 or 2 i'm not getting as good  a tone i would at 4 or 5. only a twin reverb @ 4 is omfg loud. a couple years ago i read seems like in a half dozen places about taking out a couple of the output tubes but now i swear i'm looking everywhere and can't find that information again. i'm guessing it's power tubes 3 & 4 but i just want to be sure.

[dinosaur]

I know on some Marshalls you can pull the outer pair or the inner pair, but I don't know about your amp.  You should definitely check first, as there is a good chance it's not 3,4.

Also, keep in mind it won't lower the volume all that much.  It's not going to be half as loud.  I don't know the formulas off hand, but I would guess it would still be 75-80% as loud.  It's more of a subtle change that people dig, but it rarely makes a practical difference in volume.

It also changes the speaker load, and you would change the impedance setting on a head, so I'm not sure what you do on a combo.

I'm just trying to help since there aren't too many responses on here, but I'm far from an expert.  Good luck.

[haledixon]

thanks... i found a little bit more information on it... the tubes to take out would be 2 and 4 (the outside pair). i know it wouldn't be a huge difference as halfing wattage in no way halves the volume. i would also have to disconnect one of the speakers.

i'm now looking into perhaps trying out those yellowjacket tube adapters and see how they might bring things down.

thanks for the responses... if anyone has anymore info let me know.

[mynameisjonas]

i know it wouldn't be a huge difference as halfing wattage in no way halves the volume.

that's right, the actual volume difference will only be a few decibels (IIRC the difference between 50W and 100W is 3dB). but the amp definitely will hit the "sweet spot" at a lower volume.