6L6 vs. EL-34 in Mark V

I'm curious if anyone has tried fresh 6L6's vs. fresh EL-34's in their Mark V?
I watched a comparison video and other than the cleans sounding slightly fatter with the 6L6's, it didn't seem like much of a difference.

Have done some searches on this as a new Mark V owner.
Some people feel the EL 34's give you more of a Marshall vibe in the second channel, but you lose something in Channel 1.

I like them both, I feel like there is a bit more grit with the EL-34s, especially in channel 2. 6L6's sound best for clean and channel 3, IMHO. But, I do not dislike either one.

Be aware, that the EL-34s should be run in variac power setting to avoid early tube failure. Mesa's newer user manuals explicitly state this (old one did not). I have found this to be true from experience!

I compared fresh EL34 (NOS STR-442) to used 6L6 (STR-440).
My experience is the same as mentioned earlier, Channel 2 sounds better on EL34 and I like the 6L6 more on channel 1 and 3. Tried this a few times and decided to stay on the 6L6 tubes.

Guess I will use a pair of the EL34's to re-tube my Marshall JTM60 that still has its original power tubes..

I have a quad of mesa str 447 el34's. I think I paid $100 for them, I think it was worth it. They can be very different and I enjoy them from time to time. Like everyone says, they're great for channel 2 but I think I like them with channel 3 better. I like them for c+ mode and I'm going for a kinda similar tone as channel 2 crunch mode but the c+ mode makes it a bit more aggressive, closer to an 800 than crunch mode gets, imho. A key here is volume, you have to get your money's worth out of the el34's and get them working hard. As you turn the volume up you hear them start to compress earlier than 6l6's. Also, you're tone will be a little hairier and you'll get that grind with the sensitive harmonics that the el34's are famous for. It makes c+ even more brash in way that can be enjoyable.

And my favorite with el34's is tweed mode in 10 watts with the master cranked, gain between 2 o'clock and max. You want a great classic rock tone, there it is. If you're on the fence about getting some el34's, I think they're worth it.

I liked the EL-34s in when I played with another guitarist in the band. They kind of "narrowed the band" so to speak and sounded more focused and 2 dimensional.

The 6L6s, for me, works best where I'm the only guitar like I am now. They give me a more 3 dimensional sound/feel and, IMO, they help "fill the space."

I have done many tube swaps in the Mark V. All new tubes. Best tone I ever had was with SED =C= 6L6GC tubes. Tung Sol 7581 were good too as well as the TAD6L6GC-MSTR. A Great sounding EL34 was the JJ6CA7 but had sudden death (did not know full power was bad). Awesome tubes are the Gold Lion KT77 (lasted many months of use at full power and still good, will have to put them in again. Sinister gain structure at the sweet spot).

6L6 will be more balanced and fuller in tone, chime on the top end and blossoming lows with decent midrange. EL34 (depending on variety, glass envelope size, internal structure ) will have a larger array of tones. Small bottle EL34 (mesa and EH) will be a bit sharper in gain character, a bit more sag on the bottom but not as abundant in power as a 6L6 due to differences in impedance and accentuated midrange. May even sound honky on the clean channel or enhanced grit and lack of clarity you will get with a 6L6. However, I never really used variac mode whan I ran EL34s so there may be some differences due to lower plate voltages.

I actually prefer the 6L6 in the Mark V, as well as Roadster and JP-2C (has no options for other power tubes).
On the flip side, the RA100 is best served with EL34's and the cleans are awesome. I have tried all flavors of power tubes in my amps with the exception of the JP-2C. Note that the Mesa 6L6GC STR440 does have a similar tone to the EL34 but will provide superb clarity with the clean channels since the tubes will have more overhead before breakup and the obvious abundance of bottom end. You may like EL34s in the Mark V. Depends on preferences really.

It is quite the question. I, like many of you are non-committal. I have tried both, done jobs (Gig) with both EL34 and 6L6 and I can honestly say, yep I like them both. I actually cannot find anything from either tube that I could put on the, “I don’t like” side. They just sound a little different. Neither one does anything poorly just a little different. I also like the first few days after I change. I have to do a little tweaking on the amp to get it right. Like rediscovering it all over. Cool tones and finding new ways to use them.

In the end (if I'm ever at the end?) I decided to keep my 6L6's in the Mark V because my favorite part of the Mark V is channel 1. Great cleans...I really like all 3 voices, especially Fat and Tweed.

Thanks to all who shared their experience on this thread. Helpful and interesting...including need for using variac power on EL-34's.

I am 100% on the EL34 front !!!
It made the cleans sound like my old MKII ( something have always loved )
Channel 2- I use MK1 mode with a treble heavy GEQ that I just love tons of gain and sustain that cleans up when you roll off the guitar vol
I run this channel in 45 watt mode
Channel 3 - MKIV mode 90 watts this channel has a bit more treble some would say more modern, lots of punch and gain add the preset GEQ for some extra thump and the the solo takes it over the top.
The 6L6s just didn't feel or act like the multi channel classic boogie i was looking for, it still sounded good just not my thing.

Tho there are clams I like how this sounded

https://soundcloud.com/the-pedal-guy/santana-prs-v1

Are you guys who are using EL34s also using Variac power?

Thanks.

When I was running EL34 variants, I used full power without any failures. Ran the KT77 hard for 8 months and no failures. This was prior to the announcement and update in the manual on the use of EL34. What was in print was not a recommendation as it stated the EL34 tubes will last longer using Variac power, so will the 6L6 tubes. It was that general so did not indicate amp failure or premature tube failure will result. Due to the higher plate voltage at full power, I would agree best not to run the amp at full power with EL34s.

mace said:

Are you guys who are using EL34s also using Variac power?

Thanks.

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I’ve used 34’s in my V for several years (same ones all this time). I run it fairly loud through an attenuators and routinely use full power. Also sometimes variac but mainly full power. I’ve never had a problem.