MK III Preamp Tubes

[glgarber]

Hey guys/gals

I just got an early Black MKIII from its original owner. Simul-class (though he used a quad of 6L6s), graphic EQ, reverb, the works.

Worked fine and sounded great. Then a while later, one of the power tubes lit up to a radioactive blue. Went to the local music shop and bought a matched pair of Sovtek 6L6s for the time being. Still did the same thing.

I'm planning on returning the Sovteks (if I can--I should be able to since they spent literally less than 5 minutes in my amp) and reloading the entire power tube section with a matched quad of SED =C= 6L6s (I'll save the EL34s for a later date). But I wanted to get your opinions on what to do with the preamp tubes.

I'm pretty sure the issue is from either V1 or V2 so I could just find out and replace it. But I'm also considering getting the tone kit from http://www.dougstubes.com/tonekits.html and just keeping the preamp tubes that are currently in it (the working ones) as spares. Would I be better off just replacing whichever one is down and leaving it at that?

What are your preferences for preamp tubes, by slot (V1, V2, etc)?

Also, is the V4 (Reverb) tube necessary if the reverb is never used (or not even plugged in)?

 

[boogiemon]

my understanding is that blue is not a bad thing but they should be blue in pairs imho.

 

[MrMarkIII]

You said it yourself: "Worked fine and sounded great."
Nothing else matters. If the amp works and there are no expensive noises, what's the problem? Blue glow means little or nothing. Intense red glow and a very hot tube does.
What evidence is there that the first two pre-amp tubes (V1 and V2) are causing trouble? Noise? Sound cutting out? Smoke? Flames?
There's no advantage to removing any tube. Just keep the reverb dialed down to zero.

 

[droptrd]

The TS are cool. I like the JJs better in my purple. Currently lovin a mullard in V1. Adds a ton of gain

 

[glgarber]

I guess I forgot to mention that the bright blue tube started as the amp started humming and then the volume dipped drastically. The tube was glowing bright enough that I could see it through the grill cloth.

I order a matched quad of SED =C= 6L6s and a few preamp tubes to have on hand just in case.

 

[kdorsey]

Preamp tube selection is as subjective as it gets. And unless you've played a MkIII for years, you need to get a baseline for THAT amp before making changes. Any change you make in V1-V3 and V5 will make a tonal change. So be prepared to experiment.

I prefer a combo of RFT and Tung-Sol in my MkIII. RFTs are darker and good for taming the brittleness and shrill that occurs with some speaker selections. The Tung-Sols add definition and clarity at the expense of some crunch...not a bad thing. V5 is a very special position (output drive stage) and IMO only does well with stock Mesa 12AX7s or Tung-Sol. Get a couple of each brand and try for yourself. It's a "season to taste" kind of thing.

Good Luck!

 

[boogiemon]

-

 

[glgarber]

btw. one of the vendors, tube-depot or tubestore, i forget which, has a "high-gain" option for their 12ax7s. It's another $2/tube, but my tung-sols have *lots* of balls.

Preamp tube selection is as subjective as it gets. And unless you've played a MkIII for years, you need to get a baseline for THAT amp before making changes. Any change you make in V1-V3 and V5 will make a tonal change. So be prepared to experiment.

I prefer a combo of RFT and Tung-Sol in my MkIII. RFTs are darker and good for taming the brittleness and shrill that occurs with some speaker selections. The Tung-Sols add definition and clarity at the expense of some crunch...not a bad thing. V5 is a very special position (output drive stage) and IMO only does well with stock Mesa 12AX7s or Tung-Sol. Get a couple of each brand and try for yourself. It's a "season to taste" kind of thing.

Good Luck!

I ended up getting the 12AX7 Tone Kit offered at Doug's Tubes:

12AX7 Cocktail, very popular with our customers. Great for high gain Mesa amps.
- V1 Tungsol 12AX7
- V2 High Gain JJECC83
- V3 Penta 12AX7
- V4 Shuguang 12AX7 9th gen
- V5 Sovtek LP/LPS

Thoughts? Going to use the ones that are currently in there as spares. Should be a good baseline for now I think.

 

[fishyfishfish]

That is going to be subjective question. I really didn't hear a big difference when I swapped pre amp tubes around with the exception if it was a high gain tube, it was a little hazy on the clean channel. Go with what sounds good. ( And I am not trying to be an A**hole.), and post back what you found out!

 

[glgarber]

That is going to be subjective question. I really didn't hear a big difference when I swapped pre amp tubes around with the exception if it was a high gain tube, it was a little hazy on the clean channel. Go with what sounds good. ( And I am not trying to be an A**hole.), and post back what you found out!

I'm planning on swapping them around a bit and trying different combos. That is, if the combo suggested by Doug at Doug's Tubes leaves anything to be desired.

You didn't come across as an A**hole. I was just curious of people's subjective opinions.

 

[Steve@Russo]

those tone kits look cool, anyone else do something like that?

 

[glgarber]

Hoooooooooooooly shiiiiiiiiiit.


This thing sounds BEASTLY. My Emperor 15"+10" cab came in yesterday, and it sounds killer. Plenty of low end thump and high end crispness. Eventually I'll add on a 2x12 to complete the tonal spectrum, but I'm in no hurry right now. My god.

And the new tubes TOTALLY kick ass.

 

[SonicProvocateur]

Emperor = totally sweet. I want a 6x12.

Glad everything played out well. Everything in the kit come as expected?

 

[Skyless7620]

Not to derail the thread, but which speakers do you guys use in your emperor cabs?

 

[glgarber]

Not to derail the thread, but which speakers do you guys use in your emperor cabs?

Mine are both Webers. The 15" is a ceramic Michigan 15 (voiced after the old EVs) and the 10" is a British Axis 10 (voiced after the old Fanes). Both rated at 100W, they'll both be able to handle whatever the Mark throws at them.

So glad Emperor started giving the option of Webers. They're great speakers, and unless you go with the AlNiCo versions, it's usually the same cost as the other speakers they use.

Special Walnut stain, Salt & Pepper grille. Admittedly I'm not as thrilled about the Walnut stain as I thought I would be; I think a redder Mahogany would've been better. Oh well.

 

[glgarber]

Emperor = totally sweet. I want a 6x12.

Glad everything played out well. Everything in the kit come as expected?

Pretty much. I got an extra Penta Labs instead of a Shuguang, but it was for V4, which I'm not even using at the moment.