Mesa Mark IV – EL34 or KT77?

[Metalman_666]

Mesa Mark IV – EL34 or KT77?

I love the sound of my Mark IV short head right now with all stock 6L6s, but I've really been digging the EL34 tone lately and I understand that to get the best of both worlds I should try running a pair each of 6L6s and EL34s (inside and outside sockets respectively IIRC?)

I was reading some of the descriptions of the individual tubes and retube kits on the Eurotubes site, and a friend of mine suggested the 6L6/KT77 option for me because he said the KT77s have a bit more low end than the ELs and have a really smooth, singing top end.

Have any of you Mesa guys tried this out, or has anyone done a comparison between EL34, E34L and KT77? My plan is to go with JJ tubes because the only other time I bought them was for my Peavey Triple XXX and I wasn't disappointed. I would welcome suggestions for other brands if you think they would be a better fit.

Of course, I love the Petrucci and old-school Metallica tones. I play a lot of metal but I also occasionally play some jazz and lighter rock. Is it true that the cleans on the Mark IV really suffer a bit with a British-sounding tube?

 

[Boogie Bill]

Re: Mesa Mark IV – EL34 or KT77?

Re: Mesa Mark IV – EL34 or KT77?

I don't think you can use the KT77s with the Mark IV. I don't think they will bias up correctly. You'd probably have to pay a tech to mod the bias circuit, and it just isn't worth it, IMO. You can check with the CSRs at Mesa Boogie to see what they would advise on the KT77s--and don't forget to ask the guys at the "Boogie Board" Forum at http://www.grailtone.com .

I installed Winged C/SED 6L6s and EL34s in my Mark IVa 112 combo and couldn't be happier. Another excellent choice for the Mark IV is the Mesa/Siemens EL34. I like JJs in Marshall heads, but I think there are better choices for a Mesa amp.

I like the EL34s in the Simul-Class sockets--I think it gives the amp a little upper midrange snarl--yet it's creamier, at the same time. A lot depends on how you use the power settings of the amp. Do you run Pentode or Triode? Simul-Class or just the Class A? Tweed or Full power? Mid Boost or Harmonics? Do you pull the Presence knobs or leave them pushed in? How LOUD?

The Mark IV is one of the best amps available for the guy who needs one amp that can do it all. It may take some tweaking, but it can emulate a lot of different amps. You might find that you can actually tailor you amp to the gig. Use 4x6L6s when you need clean, FULL Power, Pentode. Use the Class A setting on TWEED with EL34s in TRIODE and Harmonics for small club gigs or jazz.

Any of the REPUTABLE tube vendors can set you up with correct tubes to match the Mesa bias settings. If you do change the bias circuit in any way--make SURE he staples a notice inside the amp--so the next guy knows what he's getting into.

Good luck!

Bill

 

[Metalman_666]

Re: Mesa Mark IV – EL34 or KT77?

Re: Mesa Mark IV – EL34 or KT77?

Thanks for the wealth of info Bill! Unfortunately no one has responded to my thread on the Boogie Board even though it's been up for several days... I've sent an email to a Mesa tech recommended on the board though so I'll wait for a response.

Generally I run my Mark IV with Pentode/Simul-Class/Mid-Gain. I'm still having a bit of trouble deciding on Triode vs. Pentode, but so far the Mid-Gain voicing has the best crunch and snarl for my tastes. I leave the presence knob pushed in, and usually I'm not running it very loud because I'm at home. When no one's around I turn it up a bit though. Because of this I leave it on Tweed power.

All of this said I've only had it for maybe 5 weeks so I'm still getting used to all the tweaking. So far though, I haven't found a bad tone and I'm convinced I'll never have to buy another head ever again.

Should I definitely wait for a response from a tech or someone on the Boogie Board before jumping the gun with KT77s? I'm surprised to hear that they might not bias correctly since apparently Bob at Eurotubes has sold several of those sets. If this is the case though I might just go with the 6L6/E34L option.

 

[slightly_rude]

Re: Mesa Mark IV – EL34 or KT77?

Re: Mesa Mark IV – EL34 or KT77?

You can run KT-77's in the outer sockets with no problems. I did for a few months but didn't like the tone. They have a fizzy high end that I didn't hear with EL34's or 6L6's. I've been running (4) 6V6's now for about 9 months and I like them better than any other tube types so far. R2 is now usable (for me). The tone is a little snappier with more crunch especially compared to (4) 6L6's.

 

[Metalman_666]

Re: Mesa Mark IV – EL34 or KT77?

Re: Mesa Mark IV – EL34 or KT77?

I remember reading somewhere that KT77s have a sizzle on the top end... I can see sizzle as being fizzy. Is it something similar to when the presence knob is set too high? Would you say the ELs have a smoother top end compared to the KTs?

 

[slightly_rude]

Re: Mesa Mark IV – EL34 or KT77?

Re: Mesa Mark IV – EL34 or KT77?

Would you say the ELs have a smoother top end compared to the KTs?

Yes.

I have tried KT-77's in my Jube as well as my Stiletto. I don't care for them. They have more bass/bottom but the top end is farty. They don't have that EL34 mid punch that I'm used to.

 

[Metalman_666]

Re: Mesa Mark IV – EL34 or KT77?

Re: Mesa Mark IV – EL34 or KT77?

I suppose then in the next few weeks I'll be looking around for a good 6L6/E34L set to put in my head. Thanks a ton for the help.

 

[daemon barbeque]

Re: Mesa Mark IV – EL34 or KT77?

Re: Mesa Mark IV – EL34 or KT77?

KT77 needs more voltage to open up. It's cold and fizzy with EL34 bias. So it KT88. it's not fizzy ,but it's cold like a brick!