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Mesa Boogie Power Amp Tubes

Discussion in 'Amps and Cabs [BG]' started by tombowlus, Feb 13, 2005.


  1. tombowlus

    tombowlus If it sounds good, it is good Gold Supporting Member

    Apr 3, 2003
    North central Ohio
    Editor-in-Chief, Bass Gear Magazine
    Okay, for those of you following my venture into tube-amp-dom, I have decided to go with the Mesa Boogie Strategy 400 (thanks, RockBobby!) - at least for now! I wouldn't rule out a Demeter or Aggie in my future... ;)

    But, to allow my new (to me) Strategy to get off to the best start possible, I think I am going to just throw twelve new power tubes in there (and probably four 12AX7's, while I'm at it). The Strategy is normally configured with 12 6L6's, though it can accept EL34's in the rear bank. It is a stereo configuration, if you don't know. Also, Boogie uses a fixed bias, so I need to come up with tubes that are appropriately biased (either "Mesa Boogie Approved" or known to work properly in their amps).

    The topics upon which I am soliciting assistance are:

    1.) Does anyone have any experience with running Mesa Boogie amps with 12 6L6's versus 8 6L6's and 4 EL34's? Any thoughts at all on what type of tonal difference I might expect?

    2.) Any suggestions for specific tubes? I am not looking for an overly warm sound (I know it will be somewhat warm, but I don't want to go overboard in that direction), but I do like the complex mids of tube amps. I know the low end won't be as tight as my big old SS amps, but I'd like the bass as tight as possible, all things considered.

    3.) Where to buy my bottles?

    Thanks for all the help in prior posts and for the help to come!

    Tom.
     
  2. James Hart

    James Hart

    Feb 1, 2002
    toms_river.nj.us
    Endorsing Artist: see profile
    I won't begin to pretend I know anything about that amp or the mixing of tubes in it (doesn't sound right... 12 vs. 8 + 4).


    I'll suggest reading reviews of 6L6 tubes from around the net. Start emailing some venders / audiophiles / tube techs / long time tube amp users... take it all with a grain of salt.

    Take it to a tech to mod for an adjustable bias. THe bias points of tubes can shift over time and a few bias tweaks over the many years of life in a set of power tubes is common (or so my research tells me... I'm new to the game too).

    I ended up buying from Chris @ www.tubedepot.com I just *felt* good dealing with him / them. I went on gut instinct there and a couple hundred later and the best sounding rig I've ever had later... I've no trouble recommending them.

    (My amp takes 6550/KT88 and I went with the Sovtek KT88 over all the other current production tubes... 6L6 and EL34 are different animals entirely)
     
  3. Folmeister

    Folmeister Knowledge is Good - Emile Faber Supporting Member

    May 7, 2003
    Tomball, Texas
    I just retubed my Mesa Buster 200 and 400+ with JJs from Eurotubes all around. The Buster really sounds nice, much better than with the Mesa tubes. The 400+ had two different types of power tubes in it and I thought it was curious. I am pretty sure they were the same but looked different. This may be what you are reffering to. I put all 6L6s in it. I did not have time to fire it up yet, but tomorrow I will know.
     
  4. tombowlus

    tombowlus If it sounds good, it is good Gold Supporting Member

    Apr 3, 2003
    North central Ohio
    Editor-in-Chief, Bass Gear Magazine
    I look forward to hearing what you think about the JJ's in the 400+. I have solicited responses from several vendors. Christian is suggesting Sovtek 6L6WXT+, which appear to be 30w per bottle. Doug Preston also recommends the JJ's for bass amps. I'll digest a bit more feedback before I make the leap. Thanks for all the input, folks.

    Tom.
     
  5. I'd take it to a tech to have adjustable bias installed. Then I'd put either EH or JJ tubes in it. But, I'd try it first to make sure I was going to keep it..... :D

    We tested a whole slew of tubes last winter (including a lot of super expensive NOS ones) and the EH ones had the best distortion and gain matching numbers. Sovtek is EH but their numbers weren't as good.... I'd guess that they put the EH brand on the best of the tubes and Sovtek on the next level down.

    I'd guess you'd get more distortion at lower levels with the EL-34s. But I'm not sure...:D
     
  6. tombowlus

    tombowlus If it sounds good, it is good Gold Supporting Member

    Apr 3, 2003
    North central Ohio
    Editor-in-Chief, Bass Gear Magazine
    I did not know that this is an option for Mesa amps. Has anyone done this? What might be a fair price to have this mod done?

    Tom.
     
  7. Mesa uses 'fixed bias', but this is the type of circuit they use as opposed to 'cathode bias.' It doesn't mean that the bias voltage can't be adjusted...:D Well, it does I guess, if you don't mod it....:p Installing a bias control will expand your tube options and then you can adjust it as the bias requirements of the tubes drift....
    It's a pretty simple mod, just a matter of replacing a fixed resistor with a pot. Shouldn't be very expensive at all. It's about 1/2hr work for a competent tech.
     
  8. tombowlus

    tombowlus If it sounds good, it is good Gold Supporting Member

    Apr 3, 2003
    North central Ohio
    Editor-in-Chief, Bass Gear Magazine
    I am a man who likes options. Needless to say, I am "on it!" Thanks a lot for this tidbit of information, Mark!

    Tom.
     
  9. Passinwind

    Passinwind I Know Nothing Supporting Member

    Sure, I've done it on many brands, for many customers. I'd probably quote an hour plus parts (unless it's a major hassle to take apart) , and I'd need your new tubes in hand when I did it. If it took less than an hour, I'd charge you what it took, but it's hard to bench test an amp and work on it properly in under an hour. I prefer to burn in the tubes for at least a couple of hours, then re-set the bias if needed.

    To be clear though: I don't solicit or accept any work from Talkbassers. I've been approached a few times, and I've only caved for one guy who lives less than three miles away from me. I believe you all should develop good relationships with your local techs, if at all possible.

    Tom, you might want to read Randall Smith's white paper on the Mesa website, and decide for yourself before you do this. I am firmly on the side of doing it, but I could be "biased", being a tech. :rolleyes:
     
  10. Folmeister

    Folmeister Knowledge is Good - Emile Faber Supporting Member

    May 7, 2003
    Tomball, Texas
    Tom:
    I finally had a chance to fire up my 400+ with the JJs today. It is not the same amp, and I mean that in a good way! The sound of the JJs (this is with the eq on the amp off and dials set to what I think is close to flat + Reverend Rumblefish) is really smooth and punchy. I was worried at first because I ran it into my Powerhouse 2X10 + 1X15 and it sounded. . . good (the old tubes sounded best through this cab combo). Then I switched it to my Whappo Jr. and I was very pleasantly surprised. It's punchy, it's clear, and I adore it! I have some signal issues with the pull stops, but as of now it's a keeper for sure. I think Bob and his JJs are winners!
     
  11. tombowlus

    tombowlus If it sounds good, it is good Gold Supporting Member

    Apr 3, 2003
    North central Ohio
    Editor-in-Chief, Bass Gear Magazine
    Thanks! That is what I was hoping to hear!