Removing a tube = reducing wattage?

[catzodellamarina]

I've read a few times but not sure if it's entirely true:
To reduce wattage in a tube amp, can you simply just remove a power tube from a socket. Hmmm.. fact or crap? Will the amp be safe? Will it be stable and not lessen the life of other components not made of glass? Is it really that easy for all tube amps? How about rectifier amps? Would you need to remove a rectifier tube as well?

[rdamaral]

true but false, you can remove a tube or two, but it doesn't necessarily make the amp less loud, etc. And it will effect tone in a negative way. Really no point in removing a tube IMO.

[emperor_black]

Yes and No. Some amps you can. Some you can't. In the ones that you can, it does reduce the wattage but like rdamaral said, there's not too much "perceivable" difference in loudness between 100watts and 50 watts. So, there is no point.

Besides, more wattage means more clean headroom.

[toejam]

I could be wrong, but I think it only goes for amps with at least four power tubes. You can remove either two outer or two inner tubes.

[rdamaral]

I could be wrong, but I think it only goes for amps with at least four power tubes. You can remove either two outer or two inner tubes.

yeah, good point, I just assumed the OP meant a 100 watt head...

[bluesymetal]

I could be wrong, but I think it only goes for amps with at least four power tubes. You can remove either two outer or two inner tubes.

Thats right, you can't just remove one tube, you need to remove the matched pair.

In a 50 watt amp with 2 tubes you need to leave both in.

There are some benefits of running a 100 watt head with 2 tubes at 50 watts. There won't be a noticeable volume difference however there is some change in the tone. Which sounds better is a matter of opinion. I prefer 50 watt amps in general but that's me. Also if you take out a pair in a 100 watt head, when the two tubes that you do leave in die, you have an extra set biased for the amp ready to go! lol.

I think with recto tubes, if there are 2 in a 100 watt head and you pull two power tubes you are supposed to take out one of the recto tubes as well. I think Mesa mentions it somewhere in a manual.

Also kinda of important thing Scott Splawn told me is when taking out 2 tubes of a 100watt head, make sure you run half the ohm's you were prior to pulling the tubes. So if you were running 4 tubes at 100 watts 16ohms, you should run 2 tubes at 50watts 8ohms.

[Dreamland_Rebel]

Also kinda of important thing Scott Splawn told me is when taking out 2 tubes of a 100watt head, make sure you run half the ohm's you were prior to pulling the tubes. So if you were running 4 tubes at 100 watts 16ohms, you should run 2 tubes at 50watts 8ohms.

Great info Dude!

While 2ce the watts only makes an amp 3 dB louder, pulling 2 of the 4 power tubes will get you more power tube saturation at a lower volume -cause you'll have to turn the volume knob up a lot higher feeding more signal into less tubes than it was designed for to get the volume you had.

For instance: with a Marshall DSL100 with 2 power tubes pulled you be running your volume at about 5 while the guy with the same amp with all 4 tubes will be running his volume at about 3.
Now, both guitars will be about the same volume audibly. but the one with 2 power tubes will sound much more saturated and thicker.

[bluesymetal]

Great info Dude!

While 2ce the watts only makes an amp 3 dB louder, pulling 2 of the 4 power tubes will get you more power tube saturation at a lower volume -cause you'll have to turn the volume knob up a lot higher feeding more signal into less tubes than it was designed for to get the volume you had.

For instance: with a Marshall DSL100 with 2 power tubes pulled you be running your volume at about 5 while the guy with the same amp with all 4 tubes will be running his volume at about 3.
Now, both guitars will be about the same volume audibly. but the one with 2 power tubes will sound much more saturated and thicker.

I agree with that 100% and it's why I prefer 50 watt amps. The down side to it is less clean headroom, but most modern amps with 2+ channels have seperate volumes per channel (2 masters is getting more frequent as well) and a very loud clean signal is easy to get anyway.

[toejam]

Thats right, you can't just remove one tube, you need to remove the matched pair.

In a 50 watt amp with 2 tubes you need to leave both in.

There are some benefits of running a 100 watt head with 2 tubes at 50 watts. There won't be a noticeable volume difference however there is some change in the tone. Which sounds better is a matter of opinion. I prefer 50 watt amps in general but that's me. Also if you take out a pair in a 100 watt head, when the two tubes that you do leave in die, you have an extra set biased for the amp ready to go! lol.

I think with recto tubes, if there are 2 in a 100 watt head and you pull two power tubes you are supposed to take out one of the recto tubes as well. I think Mesa mentions it somewhere in a manual.

Also kinda of important thing Scott Splawn told me is when taking out 2 tubes of a 100watt head, make sure you run half the ohm's you were prior to pulling the tubes. So if you were running 4 tubes at 100 watts 16ohms, you should run 2 tubes at 50watts 8ohms.

That's what I thought. Good info. I've got a Carvin V3 head, and I leave it in 100-watt mode, but there is a switch to put it to 50 watts, which I know turns off two tubes. Should the ohms also be changed if I were to switch it to 50?

[catzodellamarina]

Thanks for all of the valuable responses. Yes, my question was indirectly referring to 100 watt amps. I find that 50 watts is plenty for me. I also find that when I start looking into a new live rig, the heads I like are mostly 100 watts. Others I like are the new trend of 20 and under watters. Seems to be less love these days for 50 watt heads.

[bluesymetal]

That's what I thought. Good info. I've got a Carvin V3 head, and I leave it in 100-watt mode, but there is a switch to put it to 50 watts, which I know turns off two tubes. Should the ohms also be changed if I were to switch it to 50?

Yeah that's what Scott told me. I blew a tube in my old quick rod and emailed him. He told me I can just run the matched tubes that were still good in 50 watt mode but to make sure I run half the ohms every time doing this. I don't know the technical reason why, but I take his word for it lol.

[tomanyjacksons]

Yeah that's what Scott told me. I blew a tube in my old quick rod and emailed him. He told me I can just run the matched tubes that were still good in 50 watt mode but to make sure I run half the ohms every time doing this. I don't know the technical reason why, but I take his word for it lol.

My Sovtek MIG 100 got a major overhall here recently (which sounds better everytime I use it), and I asked the guy that did the work and he said the same thing. Pull 2 tubes and half the ohms.

[toejam]

Cool. Thanks.

[Twitch]

Toe, you only need to half the ohms if tubes are removed. If the amp has a half power switch, obey amps written ohm ratings as usual(UNLESS IT SAYS OTHERWISE IN YOUR OWNERS MANUAL, Im not at all familiar with the V3, but I did have an X100B, Im just going by the most common situation). Whether it turns off tubes or changes them to run in triode mode(as opposed to pentode mode as default), if its got a switch, the manufacturer will have taken that into account for ease of users use.

Just as an example, the B52 AT100 turns the power section to class A cathode biased to make half power, and JCM900s turn the tubes to triodes instead of pentodes.

Bottom line, in your case flip the switch, stay with the ohm rating you were using for 100 watt mode. If you physically remove two tubes on an amp without half power option, half the ohms.

[toejam]

Ah, I gotcha. I don't think the manual says anything about that. Makes sense. Thanks, Twitch!