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TUBE QUESTIONS?

Discussion in 'Amps and Cabs [BG]' started by sdguyman, Mar 10, 2005.


  1. sdguyman

    sdguyman

    Jan 31, 2003
    San Diego
    I'm about to replace some of the power tubes in my Mesa Boogie Buster 2/10 combo. Its starting to get noisy and they are over 5 years old.

    I've been reading advertisements on the net for matching sets, matching quads. What does this exactly mean? The thing has 6 6l6gc power tubes. Can I just go out and buy 6 6l6gc tubes or to they have to be matched?

    The preamp tubes are staged as well, does that mean I have to buy 3 different types of 12ax7 tubes?

    I'm a newbe when it comes to buying new tubes.
     
  2. Ralphdaddy

    Ralphdaddy Supporting Member

    Nov 6, 2003
    Chicago, Illinois
    Tubes should be matched if possible as it will afford you the best sound, I'm no guru but I know this much. Get a fully matched sextet if at all possible, it is from Bob at www.eurotubes.com and most any other place should do the same. I personally like JJ's a lot, old Mullards too but they're expensive. There's tons of options out there, check out Eurotubes, www.tubedepot.com and anywhere you can find them, maybe Lord Valve. You can also order tubes direct from Mesa/Boogie. What kind of tubes are currently in there? If you like the way it sounds replace the old tubes with the same kind of tubes i.e. 12AX7's for 12AX7's, 6l6GC's for 6l6GC's etc. Different manufacturers will offer different sounds, try to decide what you like about the tone and what you might want more or less of and order a set of tubes which will match those preferences. Research is key here. Good luck bud!
     
  3. A matched set is basically a group of tubes that have very similar 'bias' characteristics. Without getting too technical, bias is how hot or cold your tubes run at 'idle'. Usually when you put a new set of power tubes in a Fender or Marshall you have to adjust the bias so that the tubes are running optimally. Preamp tubes are self-biasing. I used to have a Boogie Mark IV and I was amazed the first time I found out that, if you're content with using Mesa tubes, you didn't have to adjust the bias every time as long as you kept picking the same 'color code' of tubes that came with the amp from the factory. If I remember right, my Mark IV came with an orange set so when I went to order more tubes I just picked the orange set, popped them in the amp and kept on playing. Of course you can still fine-tune the bias to get the sound you want. There are some instances when the bias is set a certain way for an effect but without professional guidance, can damage the amp.

    I'm not sure if the Mesa bass heads, particularly the Buster, have the 'color code' feature. Of course if you want to use non-Mesa-branded tubes you'll have to have the bias adjusted every time you replace power tubes. The 6L6 is a very common guitar amplifier tube and should be easy to find sets in a ton of varieties and tonal colors. For bass amplifiers, the 6550 is much more common.

    As far as bass preamp tubes go I've been a fan of the 12AX7LPS (long-plate, spiral) since its' introduction. With the help of my good friend Robert Braught at QTS I was able to test out several different tubes in some of my preamps including the Demeter 201, SWR Baby Blue, SWR SM-400s and Avalon U5. I found I liked the sound of the LPS the most for bass (vintage and modern). The 12AX7EH (Electro-Harmonix) is also a good choice. As you become more familiar with tubes, especially preamp tubes, you will start to recognize what you like and what you don't like and come to your own conclusions about what you want to put in your amp. Remember you don't need to get a matched set of preamp tubes. That only applies in hi-fi home amplifiers.

    Looking at Mesa's site, they offer matched duets of the 6L6 STR-427 that come with your amplifier. I would suggest ordering them off Mesa's site for now until you become more familiar. I would also suggest investigating whether the bias will have to be adjusted if you get the Mesa tubes. Also if you're gonna get tubes from someone else make sure they have ultra-rigorous testing techniques. This lowers the chance you'll get a tube that is or becomes microphonic among other things. Good luck and have fun!
     
  4. Ralphdaddy

    Ralphdaddy Supporting Member

    Nov 6, 2003
    Chicago, Illinois
    While basically everything Vintage said was accurate, I have a bone to pick on one point which is this: you do NOT need to rebias the Bass 400+ EVER. It's a fixed bias amp and you can modify it to be able to adjust the bias but you don't have to. I recently retubed mine with JJ/Tesla ECC83's and 6L6GC's. It produced a tighter bottom and cleaner midrange. Maybe a little more high end but that was easily tamed through EQ. When I got mine it had the Chinese M/B tubes in it and honestly... I didn't dislike them. But a bunch had gone bad and it needed a full retube, I bought it knowing this and I went straight to JJ/Tesla because I'd heard it was the way to go with this amp. The Mesa/Boogie tubes are also a little expensive, especially the Svetlanas. I retubed my 400+ for 253.00 TOTAL, 14 6l6gc's and 5 12AX7's plus shipping. The same would've cost me over 450 from Mesa.... So my purchase was due both to money and hoped for tone. Go with your heart and your head man, you can't really go wrong it'll sound pretty solid with anything, just different flavors are available.
     
  5. Folmeister

    Folmeister Knowledge is Good - Emile Faber Supporting Member

    May 7, 2003
    Tomball, Texas
    I just retubed my Buster 200 1X15 with JJs. Bob set me up with matched tubes and the sound difference is remarkable. I would suggest talking to Bob at Eurotubes!
     
  6. sdguyman

    sdguyman

    Jan 31, 2003
    San Diego
    What did it cost you to retube the whole Buster? Did you do the 6 6l6's and the 3 12ax7s?