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:

Mesa Boogie Dual Rectifier Personal Fave Integrated Quad

Mesa Boogie Dual Rectifier Personal Fave Integrated Quad

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.

 

[GLiDE-BPM]

My Hughes & Kettner Triamp Mark 3 has 3 pairs of tube sockets. These 3 pairs can have different pairs of tubes in each one, and have them run in any combination of pairs, Pair 1 alone, Pair 2 alone, Pair 3 alone, Pair 1 & 2 alone, Pair 2 & 3 alone, Pair 1 & 3 alone, all 3 pairs together alone.
Has 6 individual preamp channels, each with full controls and each has a unique switchable boost.

I currently run two EL34's, two GC6L6's, and two KT-66's in mine (sometimes KT-88's)

The modeler of tube amps and I love love love that mother!!!

 

[MatrixClaw]

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:

Mesa Boogie Dual Rectifier Personal Fave Integrated Quad

Mesa Boogie Dual Rectifier Personal Fave Integrated Quad

www.eurotubes.com

Yeah I had a pair of 6L6s and EL34s in my Mark IV and thought it was cool until I replaced the EL34s with 6L6s and it sounded better

 

[Leperclown]

My Hughes & Kettner Triamp Mark 3 has 3 pairs of tube sockets. These 3 pairs can have different pairs of tubes in each one, and have them run in any combination of pairs, Pair 1 alone, Pair 2 alone, Pair 3 alone, Pair 1 & 2 alone, Pair 2 & 3 alone, Pair 1 & 3 alone, all 3 pairs together alone.
Has 6 individual preamp channels, each with full controls and each has a unique switchable boost.

I currently run two EL34's, two GC6L6's, and two KT-88's in mine (sometimes KT-66's)

The modeler of tube amps and I love love love that mother!!!

I have a Revv Generator 120 MKIII. They can run KT88's, 6L6's or EL34's OR a mixed pair (only needs to be re-biased). Also, my Carvin TS100 stereo tube power amp can run 6L6's or EL34's or both (per channel).

 

[laxu]

My Hughes & Kettner Triamp Mark 3 has 3 pairs of tube sockets. These 3 pairs can have different pairs of tubes in each one, and have them run in any combination of pairs, Pair 1 alone, Pair 2 alone, Pair 3 alone, Pair 1 & 2 alone, Pair 2 & 3 alone, Pair 1 & 3 alone, all 3 pairs together alone.
Has 6 individual preamp channels, each with full controls and each has a unique switchable boost.

I currently run two EL34's, two GC6L6's, and two KT-88's in mine (sometimes KT-66's)

The modeler of tube amps and I love love love that mother!!!

But do they actually make a significant enough difference? I imagine using more of them at once does, but what about just switching from 2x 6L6 to 2x EL34?

 

[GLiDE-BPM]

But do they actually make a significant enough difference? I imagine using more of them at once does, but what about just switching from 2x 6L6 to 2x EL34?

Yes, there is actually a difference between my 3 different pairs of output tubes in tone!

 

[greatmutah]

Mark IIs, IIIs and IVs had it. The V had simul class but didn’t support the option of using both tube types at once. A few things were going on with that one with the power options that it had. And the VII followed suit of the V. Previous simulclass amps could use both because the low power/15 watt mode was essentially just the class A sockets. I had a III and IV that used both. The IVA especially running EL34s and 6L6s was god tier Mark tone. One of the few amps I miss.