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He's putting in Sovtek 6l6GC WXT+ tubes...

Discussion in 'Amps and Cabs [BG]' started by Rockbobmel, Jun 27, 2004.


  1. Rockbobmel

    Rockbobmel Supporting Member

    After about 15 months my 6l6GC JJ's in my Boogie 400+ started to get funky. My tech has tried swapping out to Sovteks and the funk stopped. (Something to do with unstable voltages) I was hell bent on the fact that the tubes were young, and they should last longer.....I am dissappointed....He is replacing them with Sovtek 6l6GC WXT+. He wants me to shy away from Svetlana (or Flying C).
     
  2. Rockbobmel

    Rockbobmel Supporting Member

    Anyone tried these?
     
  3. Nightbass

    Nightbass

    May 1, 2001
    Seattle, WA
    What's "funky"?

    I had great success with Svetlanas in my Bass 400+, and when JJ came out, I liked them even better. The stock Mesa tubes are (I believe) rebranded Sovteks. And your experiences are the exact opposite...

    The lack of adjustable bias in the Bass 400+ is probably part of your problem. Has your tech recommended putting in bias pots?
     
  4. natrab

    natrab

    Dec 9, 2003
    Bay Area, CA
    I agree that it could be a bias issue. I don't know if different brands of tubes draw different biases, but it seems like the would. Since when you put in essentially the stock Mesa tube it works better and with a different brand they have a shortened life span.
     
  5. Kelly Lee

    Kelly Lee Yeah, I'm a guy! Supporting Member

    Feb 17, 2004
    Marana, AZ, USA
    I know I have just gotten into the whole tube thing but, from everything I have read having the bias matched to the tube is important. As Nightbass mentioned, adjustable bias pots would make it possible to match the tubes. It shouldn't cost too much to have it done.
     
  6. Passinwind

    Passinwind I Know Nothing Supporting Member

    I don't know if different brands of tubes draw different biases, but it seems like they would.

    Yes, but even the same brand tubes from the same production run can vary quite a bit. Mesa probably specs bias current fairly closely on "their" tubes, since they want you to use their tubes, and don't provide an easy means of using other ones. Like many manufacturers, they probably set bias on the cold side as well.

    FWIW, I do amp work for some guitar players who really prefer their amps biased hot. Four to six months lifetime is about tops for a quartet of power tubes (any modern brand) in that situation. Many Fender guitar amps will eat tubes in a year or less when biased on the hot side of the normal range, and gigged daily. OTOH, there are tons of examples of zillion year old power tubes that sound fine, from a time when bias was set by AC draw at the wall socket.

    Bobby : How did the Svets sound initially? I really like them for guitar amps, but have zero experience with them in bass rigs.
     
  7. mgmadian

    mgmadian

    Feb 4, 2002
    Austin, TX
    Actually (correct me if I'm wrong). but I think RockBobby did have an adjustable bias control installed in his 400+.
     
  8. Rockbobmel

    Rockbobmel Supporting Member

    Yes, I'm sorry, he did put in an adj bias. Prolly about 4 months after I bought the JJs from Eurotubes. Bob Pletka sent me 34mv. He said they would match the fixed bias of the amp.I asked my tech if he thought the adj bias could have caused havoc. I think it insulted him. :scowl: I also asked him about the Svets and he said they are more prone to microphonics. He had a set of the Sovtek 5881WXT+ that he tried and said the funky problem stopped. I asked him to use the 6l6WXT+ for their 20% higher output. So he ordered them
     
  9. Rockbobmel

    Rockbobmel Supporting Member

    They were JJs. They sounder excellent. Everything that was promised. I also have a 1972 V-4 with 1980s RCA or GE (I forget) 7027As in it that my tech went through. I BEAT on that amp even with it on top of my Eden 4-10 since I had it for 6 years and it NEVER flinches.
     
  10. Passinwind

    Passinwind I Know Nothing Supporting Member

    DOH! I see now that your tech is steering you away from the "new" Svets. I haven't tried those yet, but it's generally a good idea to stay away from anything new for a little while, IME. If your benchmark for longevity is old American 7027s, you're setting an impossibly high mark, most likely. Still, I don't blame you for expecting and wanting more than you got from the JJs.
     
  11. Rockbobmel

    Rockbobmel Supporting Member

    They may be still OK, just not too stable in that amp.. :(
     
  12. Rockbobmel

    Rockbobmel Supporting Member

    He did put in Flying"C" 6550 Svets im my Sunn 2000S and the amp sounds killer.
     
  13. mgmadian

    mgmadian

    Feb 4, 2002
    Austin, TX
    I'm still thinkin' of new tubes for my Mesa 400+ (possibly including an adj bias mod, too), and that's a bummer to hear that the JJs didn't last for ya. Have you spoken to Bob at Eurotubes? I'd think if you dropped close to $200 on a set of new 6L6s, you should reasonably expect them to last a while.

    FWIW, the only experience I have with the Sovtek WXT+ series is with their preamp tubes. This past weekend I tried several preamp tubes in the Bass 400+: Sovtek 12AX7 WXT+, stock Boogie 12AX7, Sovtek 5751, Groove Tubes 12AX7, and some old 12AX7s from an Eden head I used to own about 10 years ago. The differences were subtle, but the WXT+ tubes were actually one of my least favorite. Again, don't know it that's meaningful given that these were preamp tubes and you're looking at power tubes, but thought I'd pass that on.

    For power tubes, I'm considering JJs and some Shughuangs that Lord Valve likes (the Shughuangs are significantly less expensive). Hey Bobby, since you're replacing the tubes in your 400+ anyways, any interest in trying out the Shughuangs and reporting back? :D
     
  14. Rockbobmel

    Rockbobmel Supporting Member

    No, he ordered them already. I did a search on comparisons of 6l6 types, and the WXT+ were a 5,4,4 out of 5,5,5. So, I am pretty sure they will cut the mustard well. I did not talk with Bob at Eurotubes because they have a 6 month warranty. Besides, I think they are still good, just not voltage stable. :confused:
     
  15. mgmadian

    mgmadian

    Feb 4, 2002
    Austin, TX
    I know what you mean about confused... and like I said, my only experiences with the WXT+ was with preamp tubes, so who knows how that translates into power amp tubes (probably doesn't). Good to hear the ratings you found on the WXT+ were very favorable... no doubt you'll be in good shape.

    Shoot... I'm still torn about which power tubes to get, I've pretty much decided (I think) that I'll replace the set given the "tube rattle" I hear now (basically sounds like the filament within a broken light bulb). I'm leaning towards the JJs, possibly the Shughuangs to save some dough (a full set of 12 is $114 from Lord Valve). Now I suppose I'll look into the WXT+'s a bit...
     
  16. Rockbobmel

    Rockbobmel Supporting Member

    Are you familiar with tube tapping with a pencil? ...You may isolate the tube that is causing noise this way. You must be very ginger with the process..
     
  17. Rockbobmel

    Rockbobmel Supporting Member

    I'm taking the amp to practice tonight. Tech said they sound much clearer and bright compared to the 5881s. I'll post the results.
     
  18. mgmadian

    mgmadian

    Feb 4, 2002
    Austin, TX
    Very cool to hear, hope you like 'em. Would love to hear your thoughts on how they sound compared to the JJs.

    FYI, I spoke with a tech the other day who recommended the 'oven mitt test' (err...the "welder's glove test" if you're a real man) instead of the 'pencil tap test': while the amp is on, the tubes are warmed up, and your bass is plugged in and on a stand, put on an oven mitt, hit a note on the bass that triggers the 'tube rattle', and clasp each tube in succession to see if that stops/reduces the shaking noise.
     
  19. Rockbobmel

    Rockbobmel Supporting Member

    :hyper: OK, We practiced tonight and I used the amp. I thing the Sovteks have a more vintage tone than the JJs. The JJs had more of a hard sound. However, the Sovteks are very clear and all the notes were even and rich in harmonic content, but NOT Mushy. I played into an Ened 4-10XLT 8 ohm and it held together very nice. I'm forgetting the Traynor YBA200 very easily, which uses Sovtek 6550s .I have a very good feeling about these tubes. I think they are winners. I am going to be more ginger with the amp now. No more cold storage in the truck in the winter. I made a foam pad for between the amp and cab. :bassist:
     
  20. mgmadian

    mgmadian

    Feb 4, 2002
    Austin, TX
    Outstanding! :cool: ... I'll look into the Sovteks. Didya have any difficulty finding them with the "correct" Boogie rating (something like 35 mA, right)?

    Did you find the JJs to be a little mushy in the low end, even when they were new? I remember you liked the JJs compared to the stock Boogie tubes that were previously in there (at least I think I remember, anyway).

    How about the "honk factor" (the upper-midrange "cardboard" sound I've heard with some preamp tubes)? Do you find either the JJs or the WXT+'s to have less/more of this? How 'bout as compared to the stock Boogie tubes?