Mk. III Tubes - Lemme Have It!

[camsna]

Hey fellas. I just dove head-first into the vintage Mesa world. And I figured that this is the best place for information! So please go easy on me. I know this is my first post. And it seems a bit newbie. But I've searched and questioned and asked elsewhere and have decided that the people here know what they're talking about - other people don't!

ANYHOW!

I just got an old Mk III combo. And it is in dire need of some tubes (squeaky, weak, crackly, glowing...)! Pre and power - all need to be replaced! What I'm after is something akin to Dream Theater - Another Day kind of lead. Bright clean. Thick Rhythm.

Now. I know that my Mk III won't do the Petrucci IIC+ thing - and I don't want it to! I love it for what it is - but that's just the, sort of, vein that I'm looking at, y'know? Not to cop his tone. But I dig that sort of articulate and saturated lead tone!

So. What can you recommend? What's worked for all of youse?

Let me have it!

Thanks, fellas!

 

[CoG]

On the preamp side, drop balanced 12AT7s (any kind, I use EHX) in the PI and reverb if you have it. That'll be V4 (and V5 if you have reverb.) Most 12AX7s seem to make the reverb circuit too noisy.

I'm not a DT fan so I can't give you Petrucci-specific tips, but I've tried a bunch of tubes so far and I like a JJ ECC803S in V1-- this is a dark/smooth sounding tube when overdriven. Use a real quality, quiet tube in V1 or the MkIII can get pretty noisy. Any quality 12AX7 will do in V2 and V3, the differences are pretty minimal to my ear.

Power tube choices will depend primarily on whether you have 60/100 or Simul-Class.

 

[edward]

Hi camsna,

First off, welcome to the board!! Lots of opinions on tubes for MKIIIs in the archives, so go ahead and look there. But since you asked, I'll offer my opinion. Bear in mind, too, that I do not play any hard-edged metal; no ka-chunk-scooped tones for me. I like my clean channel with a bit of hair around the edges, but able to clean up with the guitar's volume. And I like the Lead channel thick and saturated, but more "classic rock" style and creamy (from Carlos to Eddie) as opposed to more "modern" shred with hyper-compressed sustain.

Overall, go with NOS tubes as I prefer them in most instances over the OEM Mesa tubes ...yes, I've A/B'd them and I *am* skeptical by nature of those touting "miracle" tubes. That said, I've found the NOS Mullards and RCAs excellent choices with good, full tone, never brittle up top, and also not prohibitively pricey. Alternatively, the current-production Tung-Sol Reissue 12ax7s are excellent sounding tubes, as well.

More on preamp tubes: I found that "gaining down" the V2, V3, and PI to 12AT7s really did much to lop off that sizzling upper end that kind of bites at you, while still yielding plenty of gain on tap and a tight-solid bottom end. You mentioned "bright and clean" ...the AT7s really delivered IMHO. You may want to try AT7s one tube position at a time and see what you hear. BTW, I kept the V1 a 12AX7.

As for power tubes, I love the NOS Siemens EL34s (is yours a simul?) ...Mesa also sells these as STR450. Really great mids with clear definition of each note, even with lush OD. Harmonics and "chime"
are lovely ...a vast improvement over the regular EL34s in there before.

For 6L6s, I still have my Mesa 430s, and haven't gotten around to swapping those out yet as they sound ok; not "bad" by any stretch. But in my other boog, the SED Winged-C is a beautiful 6L6 tube ...I like it so much I will definitely get a pair into my MKIII eventually. Thick tone when clean or dirty, and good, solid bottom and glassy (never shrill) high end.

Take it for what its worth. Hope this helps you a bit.

Edward

 

[camsna]

Thanks so far fellas! I forgot to mention - silly me - yes, it is Simul Class. And reverb. And EQ. "Blue Stripe" era.

Thanks for the AT7 tip on the reverb tube! I'll definitely give that a shot! But what's the advantage of using a 12AT7 in the phase-inverter position?

Thanks again! Keep it coming!

 

[Boogie Woogie Man]

My amp is exactly the same as yours and I found that putting an original yellow label Mullard EC83 in V1 and V2 made a world of tonal difference. JJ83s for the rest works great. The JJ803S is actually not recommended for this amp by Eurotubes.

 

[CoG]

My amp is exactly the same as yours and I found that putting an original yellow label Mullard EC83 in V1 and V2 made a world of tonal difference. JJ83s for the rest works great. The JJ803S is actually not recommended for this amp by Eurotubes.

Really? Why not?

 

[camsna]

Yeah! Why not? I mean - he just recommended it to me!

"Using one of the new JJ ECC803S's in V1 would be another option if you want a little less gain in the clean channel and a bit more of a vintage tone..."

I'd stray away, though. Long plate tubes and high-gain combos make poor bed-fellows.

Why the recommendation for an AT7 in the PI position?

 

[CoG]

The AT7 just seems to sound good in the PI. I think one thing with the MkIII is that there's enough gain available to really overwhelm the great tone of the amp, and maybe the lower-gain PI calms it down a little...?

 

[edward]

...But what's the advantage of using a 12AT7 in the phase-inverter position?

Thanks again! Keep it coming!

It helps "gain down" the entire amp. For most folks (and that certainly includes me ), the MKIII has plenty of gain on tap, more than is "usable" for my musical tastes. Exchanging any of the AX7s for AT7s will "tend" (though not absolutely, depending on the given tube and the tube position) "open up" the tone, compressing it less as there will be less gain "generated," so to speak (e.g. if an ax7 is "100" then an at7 is a 70). And by adjusting the gain in each given tube position, you are in essence tailoring the tone/dynamics of the indiv amp channels.

That said, the indiv tube still has lots say about the tone, which is why experimentation is key. FWIW, I have a mixture of ax7, at7, 5751, NOS Mullard and RCAs, as well as TungSol Reissues in both my Boogs and a Fender amp. Swap one tube in just one position, play, then trust your ears. Take lots of breaks as it is easy to get "ear fatigue." Eventually, you arrive at your final recipe ...Enjoy!!

Edward

 

[camsna]

Thanks for your response. Given my high-gain Petrucci-esque taste, I am now a bit confused. I mean. I know that the Mk III has plenty of gain on tap. So dialing it down shouldn't really hurt me. But will 12AT7s HELP? Especially in the phase inverter position?

I appreciate the help. But it's like they say - the more I know, the less I understand!

 

[CoG]

What it'll help with is getting you some tone to go along with the gain; if you slap the highest-gain tube you can get in every position in a MkIII you will have a real noisy, feedback-prone amp that has a very small usable range on each of the controls. I tried this the first two days I had mine :wink:

Tubes are cheap; try an AT7 in your PI with higher-gain tubes in V1-V3. It'll probably sound better, but trust your ears...

Those JJ ECC803s are fine in my short head, but yeah, a combo might be a bit rough on them. They're no good in my friend's Roadster combo.