Will any EL34/6L6's work in my Mark III?

...as long as the EL34's are on the outside and the 6L6's on the inside? Assuming each pair is matched?

I plan on just picking some after doing research. Open to suggestions- looking for the most harmonically rich, liquidy, sustaining, saturated lead tone. Smooth mids. Not concerned with rhythm tone. I do enjoy mixing the EL34's with the 6L6's in simul-class, but I'm open to trying all 6L6's if it might give me the tone I'm after.

Many reviews and recommendations for new production tubes can be found here:
https://www.thetubestore.com/

They need to be in the proper bias range. This isn't a option. Any decent vendor can get you tubes in the proper bias range. Just let them know what amp you are using.
Mesa sell tested tubes. Let them know what kind of music and amp and they can give you advice.

There is only two factories in the world that make tubes currently.
China and Russia. Often tubes are just relabeled and the same tube.
A big factor of relabeled is if and how much the are tested for quality. My experience is quality tubes are a very good idea.

You can usually use Groove Tubes with the 4,5 or 6 rating. Don't forget about JJ tubes. They're made in Slovakia.

What about JJ tubes? Those aren’t made in Russia, are they?
Edit: Looks like xdg999 got the jump on me!

You want a 6L6 tube pair for the outer Class A slots that bias under 50 mA (Mesa red or yellow), or an outer EL34 pair that bias in the 25 mA range (I don't know the color for ELs). For the inner A/B pair you want a pair that bias in the 30-35 mA range (Mesa grey).

My Mark III SimulClass runs about 490 PV.

Aha- so, 39mA for the EL34's would be to high?

I actually clarified with Mike B. today with some other questions I asked about mine. He did say 25-35 mA for EL34s in the Class A sockets. He did mention green or grey.

Looking here https://www.amplifiedparts.com/tech-articles/tube-amplifier-bias-calculator

With my III's 490PV, EL34s would be at 70% bias at 35 mA.

One more question- does the rating of the EL34's in simul-class affect how you should choose the 6L6's rating? Meaning, if you have EL34's on the higher side, is it necessary (or beneficial) to get 6L6's on the higher side? Or the opposite?

Thanks for all the info. I take it that we can infer from Mike B. that green and grey EL34's are in the range of 25-35mA? That's the first time I've seen a number attached to the color code.

I've tested most 6L6 Mesa colors but no EL34s as I don't tend to use them. They are not a direct cross in terms of color / output.

Technically all Mesa colors are "supposed" to work, but pragmatically if you're paying attention going hotter or colder will change the tone & the tube life. I tonally prefer my Class A/B 6L6 in the 35-40 mA range and the Class A 6L6 in the 45-50 range for Mesas. Different amps take different colors to get there. IOW the number vs. the color code is macro different with different generations of amp and micro different amp to amp.

To recap for the Mark IIIs in my experience-
- Class A. 6L6 red or yellow, EL34 grey. I did use EL34 blue in an amp a long time ago & it had a great snarl but that was before I tested things.
- Class A/B, 6L6 grey.

This color advice does not apply to Mark IIs, IVs or Vs. I've tested all those, too.

Awesome info. I panic-bought some matched Mullard EL34's (39.3 and 39.4mA), because I thought one of mine was bad and needed replacement asap, due to a blown fuse.

In the meantime, I've found places where I can get those at a lower rating (in the range Mike B. suggests), but I will still try these. Maybe I'll get an enjoyable "snarl," as you put it.

I'm a big fan of the newer Tung-sols. I would go to Tube Depot. Just tell them the type of amp and they will match. I've been buying from them for years.

Out of boredom, I swapped out the EL34's (Mesa 416) and put two Sylvania 6L6's in the class A slots, with Mesa 415 6L6's in the a/b slots.

Observation:

Mids and high were suddenly much smoother. Tone seemed sweeter in class A mode, even at lower volumes. Am I onto something in going with four 6L6's for the lead tone I'm looking for? Or could it just be that the Mesa 416's aren't the right EL34's for me?

erickompositör72 said:

Mids and high were suddenly much smoother. Tone seemed sweeter in class A mode, even at lower volumes. Am I onto something in going with four 6L6's for the lead tone I'm looking for? Or could it just be that the Mesa 416's aren't the right EL34's for me?

Click to expand...

I'm not a big fan of some of MESA's EL-34s. They do however have NOS EL34s of the SED =C= tubes (last I checked several weeks ago). They are pricy, but well worth the $$$$$$.

I still have a stash of them and swear by them. Again the TUNG-SOLS EL34s aren't bad either.

However the 6L6s will be smoother and a different tone altogether than EL34s. Little cleaner break up, not as vintage sounding as the 34s. I like the 34s b/c of their "bell tone" in the breakup higher up onthe neck.

Just my 2¢

Good point re: "bell tone" - I do love that sound, and like to emphasize it. My current setup will do for now until my new goodies arrive!

Check this comparo I did.

https://youtu.be/LZyCPAF7buM

FTR- I retract everything I said about Mesa STR 416's (which are Sylvania EL34's, I believe?)

They are the best sounding tubes I've used in the Mark III DRG, running the Studio Preamp through the fx return. With the Mesa STR 415's in the A/B sockets, it's the best tone I'm getting out of this setup with all of the combinations I've tried.

It was actually something about the voicing of the Mark III itself that I wasn't crazy about, and my earlier swapping of tubes made me think I had solved the problem.

In my experience, yes. I haven't been impressed with EL34s in my Red Stripe. However, 5881s can compress nicely and seem to sweeten spiky highs if that's your thing. They sound best to me in the outer sockets where you's put the EL34s.