Can You Do Both EL34 & 6L6 Together?

[MirrorProfiles]

@MirrorProfiles are you referring to...

Extended Class A is a technique that uses a triode and a pentode (or beam power tetrode) on both sides of a push-pull output stage.​

I’ve seen a few amp tech’s mention that when Mesa has Class A labelled on the amps it’s more of a marketing thing and that it isn’t really running in Class A. Guessing it was on Psionic or Brad’s Gear Garage videos but I can’t remember where.

Theres some posts from TOP here too https://www.thegearpage.net/board/index.php?threads/mesa-boogie-simul-class-biasing.1150505/

 

[EOengineer]

The Mark VII is simul-class, but you can’t mix tube types. There’s a bias switch for either 6L6 or EL34.

As for the EL34 & 6L6 together - it really is awesome and should be available in more amps. To my understanding it’s available in the simulclass Mark II, III, & IV amps, the Road King I and II, and the 2:90 power amp. I do not know about the 50/50 power amp, but I doubt it.

I have a Mark III DRG that I run in 2x6L6 and 2xEL34 and it sounds awesome, and that’s my favorite setting for heavy rhythm guitar on the RK2 as well.

My Mark III is simul-class though I’m currently using 6L6 in all positions. I know there are also IIC+ amps that are simul, not sure if those were the first. The III and IV definitely had versions that were.

I like to tell myself it adds some sweetness to the amp, but who the hell knows. Could be magic beans for all I know.

 

[gearJunkie]

And of course the big boy STEREO SIMUL-CLASS 2:NINETY™ has it in its name.

 

[Desertdweller]

And of course the big boy STEREO SIMUL-CLASS 2:NINETY™ has it in its name.

The VII has an alternate name on the back of the chassis as well, the Simul-Seven.

 

[gearJunkie]

The VII has an alternate name on the back of the chassis as well, the Simul-Seven.

View attachment 21138

Yes, the implementation within the Mark VII is directly tied to its power scaling.

 

[TSJMajesty]

Simul-class is running one pair of tubes in class A and the second pair in class A/B.

^^This

 

[TSJMajesty]

And of course the big boy STEREO SIMUL-CLASS 2:NINETY™ has it in its name.

And per Eurotubes, "The 290... can run a quad of 6L6GC's along with a quad of EL34's, E34L's, KT77's and 6CA7's."

 

[Desertdweller]

Yes, the implementation within the Mark VII is directly tied to its power scaling.

Can you add some detail to this? I'd like to learn more.

 

[HomespunEffects]

My Dual Rectifier had a pair of 6V6s and a pair of KT77s. It sounded much better when I replaced them with 4 6L6s.

I’m not sure what this was supposed to accomplish but it wasn’t very good:

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www.eurotubes.com

 

[gearJunkie]

Can you add some detail to this? I'd like to learn more.

I believe that the full wattage setting is one pair of power tubes in class A with the other in class A/B.

The middle wattage setting is only one pair in class A pentode and the low wattage setting is only one pair in class A triode.