Looking for new tubes

[AndrewB]

I have a Marshall MA50 head, and I'm looking to replace the power tubes. I'm gonna be using it for a lot of metal tones, so I'm not going to use EL34s, as it already sounds pretty British-voiced. I was looking at 6l6s, but apparently they are a different kind of power tube, and I couldn't put in the 6l6s without modding the amp.

What tubes would have a less mid-rangey characteristic to them?

 

[Trevoire520]

Maybe KT77's? Or is it 88's that can go in EL34 slots? Whichever one it is it apparently has a bigger low end than the EL34's.

 

[TheWinterSnow]

6L6s would work in the amp, you just can't place EL34s in a 6L6 amp. With that said, I really wouldn't recommend running KT88s for multiple reasons, KT77s and 6L6s are your best bet.

 

[AndrewB]

I read on one of the Marshall forums that you can't replace EL34's with 6l6's because EL34's are pentodes and 6l6's are tetrodes, and they also operate at different plate voltages.

 

[TheWinterSnow]

I read on one of the Marshall forums that you can't replace EL34's with 6l6's because EL34's are pentodes and 6l6's are tetrodes, and they also operate at different plate voltages.

Not entirely accurate, but close. EL34s are Pentodes and 6L6s are Beam Power Tedrodes which operate in the same manner, in the case of an EL34 and 6L6, each of their 5 electrodes run on similar voltages and for most brands, have the same exact not to exceed voltages on the screen and plate (anode) typically 450v for the screen and 500v for the anode however most EL34s can actually have to to not exceed anode voltage much higher than 6L6s however I have never heard of an EL34 amp have an anode voltage greater than 500v. This plus the typical filament current of both tubes would and the information I noted above would point to the conclusion that it would be perfectly safe to run a 6L6 in and EL34 amp unless the anode voltage was in excess of 500v which again I highly doubt you would run into an amp with such anode voltages for a 50 or 100 watt amp.

Worst case scenario is if you put 4 6L6s in a 100 watt EL34 amp, you would get less than 100 watts becuase the screen voltage would be lower than what a 6L6 needs. There is nothing wrong with this because it would just mean that the amp would get power amp saturation at lower volumes and the 6L6s would have a longer lifespan.

Put it this way, typical operating voltages for each electrode would put a 6L6 as a better replacement than an KT88, however the best replacement would be a KT77 but they sound very similar to an EL34.

 

[lolzgreg]

My answer to this is that power tube choice is not going to be the deciding factor in order to make your amp "metal" sounding. EL34s can do "metal" just fine. The Framus Cobra runs them... Rectifiers can run them... The Marshall JVM runs them... tons of awesome sounding Marshall amps that can brew aggressive tones also run them. I think your best bet would probably be to sell your amp/return it, and buy an amplifier that produces tones you know you love.

 

[::XeS::]

+1

 

[Wohma]

My answer to this is that power tube choice is not going to be the deciding factor in order to make your amp "metal" sounding. EL34s can do "metal" just fine. The Framus Cobra runs them... Rectifiers can run them... The Marshall JVM runs them... tons of awesome sounding Marshall amps that can brew aggressive tones also run them. I think your best bet would probably be to sell your amp/return it, and buy an amplifier that produces tones you know you love.

ENGL Savage 60 and many of the newer ENGLs (Invader, SE) have EL34s - and they sound "metal" enough to me