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SED SV6550C for Mesa 400? (not plus)

Discussion in 'Amps and Cabs [BG]' started by stevekim, Oct 16, 2005.


  1. stevekim

    stevekim

    Feb 11, 2000
    los angeles, ca
    I am thinking about retubing my mesa bass 400 with SED SV6550C's. Can anyone comment on these tubes or suggest alternatives I should look into? I am running stock mesa power tubes right now and while I am fairly happy with the mid to high range tones the low end sounds like mush. I really like the overdriven sound i get in the mid to high range but in the lows i loose too much definition.

    Thanks,

    steve
     
  2. vivaknoxvegas

    vivaknoxvegas Gold Supporting Member

    May 6, 2002
    Knoxville, TN
    I am in the exact same boat right now. I am retubing my 400 for sure. It's not based on need, but want. I want to get the most that I can out of the 400.

    I can't decide between 6L6s, 6550s, or KT88s. Sovtek, JJ, SED, Tung Sol, Mullard. Everyone says something different so I may just have to bite the bullet and pick something.

    Tube Depot recommended SED-6L6s or Sovtek 6L6WXTs and Mullard preamp tubes. Of course eurotube recommended JJ-KT88s.

    I think that maybe this question can't be answered on a message board. I am about to the point where I think it comes down to picking something quality and just trying it out. This doesn't sting too bad with preamp tubes but with power tubes it gets tough.
     
  3. Hoss

    Hoss

    Jan 9, 2006
    Vienna, Austria
    Maybe this can help you...
    Or confuse you even more. :D

    http://www.watfordvalves.com/cgi-bin/documents/testreport_42.pdf

    I have a sextett of the SED 6550s in my SVT and I love the sound of my amp. Just be sure the tubes are really well selected and matched. Probably the factor of selection is even as significant as the brand of tubes itself.
     
  4. brothernewt

    brothernewt Some people call me the stormtrooper of love...

    Apr 13, 2004
    Happyrock, OR
    I have them in my SVT-II also... and it's got a little tighter low end than my VR (with stock tubes... can't recall just now which they are). Of course... doesn't mean they'll do the same for the Boogie.

    The first 2 posters should each buy a different set and swap after 30 days...
     
  5. This info is an advertisment and little more. There are no specified operational voltages, nor are there power measurements. IME, Svet/SED/ whatever they're calling them this week tubes do NOT put out full power of for their type, nor can they do so without going into runaway, specifally in an SVT. A Bass 400 runs its tubes a lot easier, so it's not such a big deal. But I get real put out with all the glowing reviews of SED 6550C's that are conveniently vague on technical details. I have 100 of them in various matched sets and I would LOVE to use them, but in most of my big bass amps, they just don't work.
     
  6. Visirale

    Visirale

    Mar 23, 2003
    Orlando
    I'm running KT-88s in my non plus 400 and I absolutely love it. I don't have anything to compare it to, but don't feel the need to do so.
     
  7. brothernewt

    brothernewt Some people call me the stormtrooper of love...

    Apr 13, 2004
    Happyrock, OR
    I'm not disputing technical data here, but they sound good to me... and at least in my amp seem to do what the OP was looking for: a little tighter bottom. It does make sense... seems a tad quieter than with the previous tubes or the VR.


    I'm sure you've posted before and I've missed it... but what does work? I'm sure it applies to the original question too.
     
  8. vivaknoxvegas

    vivaknoxvegas Gold Supporting Member

    May 6, 2002
    Knoxville, TN
    What preamp tubes are you running with the KT-88s?
     
  9. Hoss

    Hoss

    Jan 9, 2006
    Vienna, Austria
    I know that the SEDs are technically lower in output than eg the 6550 EH. BUT: They sound bigger. I had 6550 EHs and they sounded weaker (To be fair it was a lousy set). Also do the 6550WE in the VR I tried. But thats maybe a matter of the driver tubes and maybe different circuit that we recently discussed...

    Anyway. Probably everybody has his own taste of how the svt should sound.

    If you want to give them SEDs a try - look out for a really good selected and matched set. They should be good for about 700 Volts and run in ANY Tubeamp thats good for 6550s.

    I can recommend either watfordvalves or Tubeampdoctor (have them myself).
     
  10. vivaknoxvegas

    vivaknoxvegas Gold Supporting Member

    May 6, 2002
    Knoxville, TN
    Actually, I was wrong. Tube Depot recommended the SED6L6GC tube for my Mesa 400.
     
  11. Visirale

    Visirale

    Mar 23, 2003
    Orlando
    Took me a while to find this in my email (not taking my head apart, lol). I got what bob reccomended:

    (2) standard ECC83S and (2) balanced ECC83S.
     
  12. okabass

    okabass

    Mar 19, 2005
    Finland,Lahti
    Last autumn I put JJ KT88s and a bias pot to my friends Mesa 400. He's been very satisfied, and feels they're a way better than 6L6s. We also changed the "last" 12AX7 to AT (My 12AU7 supply was temporary finito). He likes it. He says he's going to try also 12AU7.