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Retubing a Mesa 400+

Discussion in 'Amps and Cabs [BG]' started by Folmeister, Dec 18, 2004.

  1. Folmeister

    Folmeister Knowledge is Good - Emile Faber Supporting Member

    May 7, 2003
    Tomball, Texas
    Hear Me, Bass Gods!
    I just picked up a used Mesa 400+ and I am digging it. I have to retube it, and I am considering going with the tube package Bob from Eurotubes has to offer. Now, is the replacement process something that I should attempt myself? I am a long-suffering solid state troll and I did not find any useful advise on the Mesa site. So, how easy is this to do? Is this advisable at all?
  2. r379


    Jul 28, 2004
    Dallas, Texas
    I'll suggest one thing: Don't get fingerprints on the tubes. If you remember the picture of Bob on his website, he's wearing gloves handling that tube. Supposedly, fingerprints will cause hot-spots on a tube. A ham radio guy I used to know was a fanatic about that.
  3. replacing tubes is pretty easy, well with my Mesa Walkabout at least. It came with the tubes packaged seperatly. All i had to do was open the head up, and plug them in. All i had to worry about was being careful to support the board so when plugging them in i didn't push to hard and damage it.
  4. James Hart

    James Hart

    Feb 1, 2002
    Endorsing Artist: see profile
    why are you changing them?
  5. Folmeister

    Folmeister Knowledge is Good - Emile Faber Supporting Member

    May 7, 2003
    Tomball, Texas
    When I picked up the head, the dealer told me that half of the power tubes had been replaced by a local Mesa tech and the others were what was considered salvageable of the originals. He was very honest in that in return for a $499.99 price (yeah, you heard right), the other tubes would be best changed out. So, I did a search and learned about Eurotubes and emailed Bob. I can do a complete retube for $225 shipped. Seemed reasonable to me, and I supposedly did not need to bias them. Now I am wondering about doing it myself.
  6. well if you have stock Mesa tubes in there, at least you'll be upgrading your sound by using JJ"s. Just be carefull how you put them. if you mess up you might end up with some tube rattle.
  7. I guess I'll have to repeat James Hart, why are you retubing it? Is there a problem?

    Just because some tubes are original, and some aren't, doesn't necessarily mean a retube is in order. Search through threads here and you'll find many people, myself included who have amps with 30 or 40 year old preamp tubes in them...believe it or not!!
  8. Folmeister

    Folmeister Knowledge is Good - Emile Faber Supporting Member

    May 7, 2003
    Tomball, Texas
    Could you describe common problems associated with "tube rattle?" How would I know if it happens?
  9. that happens if you don't secure the tubes nice and thight on the sockets. The Mesa is a powerful ampl that will rattle the cab. That might make the tubes loose insided and rattle. youll only hear it a low volumes. fully cranked it's inaudible.
  10. Unless you've noticed a problem, don't worry about it. I'm not going into go into the myriad of reasons why you should ONLY have a tech replace your output tubes, but if the amp's working fine, why mess with it?

    BTW, any "tube rattle" (it's called microphony) has to do with the quality of the BUILD construction of the tubes themselves and how well you treat them when in use. Installation has ZERO effect on it.
  11. Folmeister

    Folmeister Knowledge is Good - Emile Faber Supporting Member

    May 7, 2003
    Tomball, Texas
    I would rather not retube the beast, but the Mesa tech recommended it. I have to believe that there is some validity to the recommendation. For the price of the JJs, why not? If the tone is better, and I love better tone, I think it may be worth it. Also, the Mesa manual actually recommends retubing every two years! I have to retube my DB 728 and that, I know, is beyond me because of the biasing.
  12. I've seen more than one "Mesa certified tech" that had no business inside ANY amplifier. I'm not saying that's the case here, but my experience with Mesa's certified techs has ALL been bad. Of course Mesa is going to recommend you buy their tubes every two years. Tubes are a high profit margin item, much moreso than their amps. Two years is just enough time for their current draw to drift slightly with age and them to emit less, so when you put in new tubes of the same rating, they'll be louder and sound 'better,' when in harsh reality, a minor bias tweak would have the 'old' tubes doing exactly the same thing without buying twelve new 6L6's.

    If you REALLY want optimal tone and performance out of the amp, forget the idea of "retubing for tone" and have a good tech install an adjustable bias control so that you can get the maximum life and power out of whatever tubes are in the amp, THEN get the JJ's. Mesa's "tube rating system" is a scam to sell tubes, NOT get the most out of your amp. Any time you change output devices in ANY type of amp, tube or solid state, you bias them for maximum efficiency and longevity. Did I also mention Mesa's tubes are generally pretty low in quality as well?

    I'm curious; what's up with your DB728? Also, regarding the earlier comment about having to wear gloves to handle tubes; it's completely unnecessary. At the temps and conditions amp tubes operate, finger oils won't hurt or even affect a thing.
  13. Folmeister

    Folmeister Knowledge is Good - Emile Faber Supporting Member

    May 7, 2003
    Tomball, Texas
    Thanks for the heads-up! I will investigate the bias control! My 728 has exhibited some behavior that the Aguilar techs have interpreted as a tube, or two, going bad. Sometimes when I engage the standby switch all I get is a crackling, distorted noise. Sometimes it does this before emitting proper tone, and once that was all it did before I shut it down and waited a little while. It fired up the second time. What does that sound like to you?
  14. slacker


    Nov 27, 2001
    Portland Oregon
    PBG speaks the truth about Mesa Certified Techs. It took me a few experiences to figure it out. I'm a slow learner.

    I have dealt with three different Mesa "techs" in three seperate stores. All three repair jobs left me cold.

    1) The choke coil on my Bass 400's 40Hz EQ slider broke off right at the coil, making it impossible to resolder. Instead of ordering a new coil, the tech just replaced it with a piece of uninsulated wire. He used a copper ground from a scrap of romex! The 40Hz slider was now a full range volume control.

    2) My M-2000 was damaged in shipping. All damage was cosmetic, and involved the face plate. My local dealer had it for over 2 months and finally returned it to me with a new face plate installed. Funny thing was, now it didn't work. Totally DOA.
    I had them ship it to Mesa (on their dime, of course).

    3) When I was young and stupid, I had my 400+ retubed. I thought: "2 years? It must be time!" Took the amp to a Mesa tech for "Official Mesa Replacement Tubes." The retube went fine, but the tech wouldn't give me my old tubes back. He got really nasty about it, in fact. Score 12 usable tubes for the tech.

    Long story short: Do your homework and find a talented tech in your area. Avoid Mesa "techs" at all costs. I'm sure a they must have one or two who know their chicken, but I ain't about to go looking!
  15. Folmeister

    Folmeister Knowledge is Good - Emile Faber Supporting Member

    May 7, 2003
    Tomball, Texas
    Thank you for sharing your experiences! I will drive it up to M/B for any repair work!
  16. I think the point that PBG's making (along with the other folks)...if you find a reputable amp tech, then avoid Mesa altogether.

    Mesa will try to sell you a new set of their "premium" tubes, most likely. And I think you could probably forget about Mesa installing an adjustable bias pot, "that ain't the way the amp was designed, that's why you buy our pre-selected high dollar tubes..."

    If you find a good amp tech and get him/her to install the adjustable bias, then your tube selection becomes much easier--and considerably cheaper. And for non-warranty repair work, I suspect a good local tech would be cheaper as well.
  17. It sounds like a bad standby switch arcing internally. It could be tubes, but that sounds like a problem with the switch itself.
  18. iualum


    Apr 9, 2004
    What is a reasonable price to pay for a bias control installation job?
  19. Benjamin Strange

    Benjamin Strange Commercial User

    Dec 25, 2002
    New Orleans, LA
    Owner / Tech: Strange Guitarworks
    Two thoughts I have about this thread:

    Remember that bias affects tone. If you are going to install an adjustable bias, the where you set your bias and what bias the tubes are at will affect the performance of the circuit. Mesa (like everybody else) designs their amps around the tubes, so changing the bias will change the tone. That said, I don't think that's a bad thing necessarily. Just keep that in mind. Also, tubes shouldn't wander so far out of spec to the point that it will affect the amp terribly. Tubes bias can wander up and down, but it's not like they will wander WAY off. I'd suggest just to buy tubes that fall within Mesa's "factory set bias" and not bother with a modification of the amp, unless you want tubes that run hotter or colder - which will affect tube life one way or another. There's plenty of tube dealers that will sell you tubes that will match Mesa's spec, and you won't have to shell out for a bias mod.

    Secondly, if a Mesa certified tech is bad, then Mesa needs to be told about it. If they don't hear about problem people, then those people will continue to get business they don't deserve.
  20. Nightbass


    May 1, 2001
    Seattle, WA
    I agree, and it would also be nice if Mesa would get with the times and have a public email address. It may be my imagination but a lot of the Mesa questions I see on TB appear to be from people who can't or won't call Mesa, and could easily be answered via email. After all, I don't see the same type of questions about other mfrs.

    What's up with them? Why won't they publish an email address? Even Mica and Ron have them. :D