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tubes for 400+...jj's vs. svetlana's

Discussion in 'Amps and Cabs [BG]' started by thetaurus, Aug 28, 2003.

  1. thetaurus


    May 28, 2002
    Muncy, PA
    i'm going to retube my mesa 400+ (it needs it badly). anyway...i'm stuck between the following sets:

    svetlana 6L6GC's w/ 12ax7eh's
    jj electronic 6L6GC's w/ jj 12ax7's

    i've heard good things about both. they're both in the same price range. i'm looking for a thick, balanced tone, and something that will go LOUD and not break up/distort too quickly. i've already emailed lord valve, but he hasn't gotten back to me yet, so i wanted to hear your opinions. thanks.
  2. Go with the JJ's. Svet tubes have taken a nosedive in quality in the past few years. Their power tubes have a tendency to become VERY microphonic under normal operating conditions and that will damage your amp as well as sound like crap.
  3. thetaurus


    May 28, 2002
    Muncy, PA
    awesome...thanks alot.
  4. Psycho, I took your advice and got the JJs. I also had the adjustable bias installed. The amp came back yesterday so I'll be using it tonight. I really don't know what to expect. The tubes were matched at 34ma. That was the recommended range from Bob Pletka.
  5. Psycho, Do the tubes need the bias re-adjusted after a while? or do they stay stable? Thanks, Bob
  6. If you notice any cherryplating or funny noises, get them checked. Good tubes may or may not drift. A 400+ is pretty conservative and shouldn't really put too strain on them.

    Is that Bob from Eurotubes? I've never dealt with him personally, but I've heard nothing but good things from those who have. 34 mA is right in line for max clean power.
  7. Physho, Yes that's him. I talked with him on the phone and he was very informative and straight forward. I told him that I wanted max clean power. He said 34ma was the chioce........... So would it be safe to say that if Mesa has an acceptible operating range, having an adjustible bias now installed, It will be more fine tuned??
  8. It will be easier to make adjustments and experiment with settings. 34mA bias is just under the recommended 35 mA operation for AB1 and will allow the tube to run a little hotter for more power.
  9. The gig went well. I had a very together sound. It seemed tighter than before. Hard to tell, but I was very satisfied. I got a nice mid growl with a very solid low end. The B string sang with no complaning. I use my BDDI for a while, but turned it off and got a more natural sound. I went in humbucking mode with a pick mostly except in a few songs with finger style. Then I used passive single coil mode. TUBES RULE....!!!!
  10. mgmadian


    Feb 4, 2002
    Austin, TX
    Resurrecting this thread: I just picked up a Bass 400+ and am contemplating new tubes. It seems certain that at least one power tube (Boogie STR-430s) is bad: it doesn't light up, and I hear a distinct sound when playing/moving the amp like that of a broken filament within a burnt-out lightbulb (know what I mean?), except it's louder.

    Anyway, JJs seem to be popular (together with an adj bias mod). Psycho: do you also prefer the JJs over the SED 6L6s, which I understand to be the new name of the original Svetlanas?

    Long shot...anyone try both SEDs and JJs in their Bass 400+?

    Interesting side-note: I just drove the amp up to Boogie earlier this week to have them take a quick look at it, and they said "It's perfect, all tubes are good + everything tested Normal". Then on the receipt I see it indicated that the amp put out 275 Watts at 8-ohms... which is exactly 11/12 of the full expected power... which seems to be consistent with a single, bad power tube. I'd think its pretty unlikely that this tube somehow broke itself on the drive home in my car... ???
  11. The "SED" tubes are the Svetlanas I was referring to. They're crap for bass amps. I've not tried any of the "new" Svetlana branded tubes which are made by Sovtek. I have heard good things about EH's new 7591, which is the industrial version of a 6L6GC, so you might want to check them out, too.
  12. mgmadian


    Feb 4, 2002
    Austin, TX
    Gotcha...thanks. This together with several reliability concerns I've heard mentioned leads me to conclude they're not a good option here.

    Last one: I've also had recommended to me the Shuguang 6L6s, as they supposedly sound good for bass, can 'play well' w/the fixed Bass 400+ bias, and are relatively inexpensive ($115 for 12). Anyone have experience with these in a bass amp (esp. the Bass 400+)?

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