Help A Toob Newbie With His Mark III?

[Jergason]

Hey, I recently purchased a purple (i think) stripe Mark III from Music Go Round. I love it, but it is really noisey, and the tubes glow with a red-orange color. It just has the stock Mesa tubes in it. I have owned tube amps before, but never replaced tubes. So what I am wondering is, should I get new tubes for the amp? If so, will I have to re-bias the amp (even though I have no idea what that means)? I want a bit more gain in the rhythm 2 channel, so any suggestions for what kind of tubes to get? And finally, one more question for you to laugh at me for asking. What is the difference between pre-amp and power amp tubes? Which ones are the ones you can see, and do I have to replace the other ones as well? Thanks for bearing with me.

 

[axwielding1]

Power amp tubes are the big ones. If you get Mesa branded tubes, you will be OK to just plug 'em in. Pre-amp tubes are the little ones, any will work fine, no biasing..
If your amp is a simul-class amp ( marked on back) with a class A / simul-class switch, then you can use 4-6L6 power tubes or 2 EL34 in the outer two sockets, and 2 6L6 in the inside pair.
Typically, old Mesa's like yours would have a Mesa SPAX7 in the first pre-amp tube, the one with the aluminum cover.
I'd replace 'em all.
You could get JJ tubes, which are highly acclaimed on all forums, but when ordering, make sure to state that it's for a purple stripe Mesa Boogie Mark III, and he'll set you up with what you need for your amp...
Good Luck.
ax. :twisted:

 

[Brewski]

The JJ's are great tubes. It made a world of difference in my amp from what it sounded like before changing them out. Let Bob at Eurotubes know that you want high gain and he'll give you the right tubes. The more detail that you can give him, the better he can match the tubes to your desired sound. Delivery on them is pretty quick too. I got mine in just several days of ordering them. https://ssl.eurotubes.com/index.htm

You won't need to set bias, because Mesa Boogie does not use adjustable pots, so the bias is fixed on a Mesa amp. You would need to modify your amp to do so. If you look at the Eurotube site, there is a section that describes biasing under FAQ's.[/url]

 

[Jergason]

Thanks a bunch guys. Ill give Eurotubes a try.

 

[zeppman]

You'll be happy with them. The only other thing I would suggest trying is some NOS stuff as far as pre-amp tubes, just because they are fairly easy to find, and can offer a lot of versatility in tone. But go with JJ power tubes, just because bob at eurotubes can really tailor them to your needs.

 

[Kgry]

I'll third the JJ recommendation. I have JJ's in my blue stripe and they rock. I plan on getting my preamp tubes from him as well. He has a high gain preamp tube and a regular. He'll hook you up.

 

[RussB]

JJ 6L6's don't draw much natural plate current. I put a set of Euro-Bob's "hottest" in my MKIII, and they were pulling around 7mA of current. Not good, and the tone suffered!

A set of SED 6L6's from Lord Valve draw around 24mA. Now we're talkin'!

I do not recommend JJ 6L6's in a MKIII

 

[marklyn]

JJ 6L6's don't draw much natural plate current. I put a set of Euro-Bob's "hottest" in my MKIII, and they were pulling around 7mA of current. Not good, and the tone suffered!
A set of SED 6L6's from Lord Valve draw around 24mA. Now we're talkin'!
I do not recommend JJ 6L6's in a MKIII

This was the exact recommendation from Doug at Doug's Tubes. Exactly his concern with the JJ's tubes and the exact SED 6L6 set.

That said, I've got JJ's in the preamp and they sound great!

 

[Timbre Wolf]

I just want to voice a second good word for Doug Preston at Doug's Tubes ( http://www.dougstubes.com/ ). He really listens to your specific needs, has lots of experience, and has always been right on my target with his recommendations.

 

[Jergason]

Hrmmm, controversy. I was thinking of getting the EL34 and 6L6 set from Eurotubes, but apparently that is not the best way to go? I guess I will sit on it some more. Is the problem with the JJ tubes not drawing enough current related to the fact that Mesas aren't biased? I am confused about why that would make a difference in tone.