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The end-all SVT Tube post..Opinions required.

Discussion in 'Amps and Cabs [BG]' started by zenlowend, Feb 25, 2008.

  1. zenlowend


    Jan 26, 2008
    Ok my fellow lowenders. I have read post after post about what tubes are best for SVT power and pre section with no real answer. Before someone says it; I know this is a subjective thing. With that in mind there are good and bad tubes and the reasions for them. So I propose we end this debate now! Post here with opinions on your favorite tubes and please go into detail, experiences live or otherwise, pic's, sound clips, places to get the best deal on tubes, 6550 vs KT88, NOS vs New, all that good stuff that us "tube heads" thirst for...tube knowledge!! So let her fly... I will start things off by asking the question: Has anyone tryed Ruby Tubes KT88 in a SVT? And, like I said, please go into detail. And away we go!
  2. Cant help on the Rubies.

    Only tried two sets of pre tubes and two sets of power tubes in my SVT.

    original pre tubes were "china" labelled 12AX7s and Amperage 12AU7s, swapped them for JJ's, which gave a much clearer sound.

    original power tubes were Philips ECG 6550A (Sylvanias), now ive got Svetlana 6500Bs.

    Not a huge fan of the 6550Bs, they are just missing something that those Sylvanias had. But, if you find the price on six NOS sylvania 6550s, you'll see it isnt too viable an option :(
  3. zenlowend


    Jan 26, 2008
    Yeah I also heard the 6550B was not a good tube at all.
  4. Willem


    Dec 26, 2005
    My tech says that if you just select the best built tubes out of a batch (by excessive testing) you will not hear any difference between different brands of tubes because the amps characteristics will overshadow those of the tubes. Besides it's pretty obvious you will hear a difference between used and new tubes anyway.

    It's just that not all tube selling companies do those tests... most of the time companies who give you the best price are the ones that are selling tubes that more expensive tube retailers have labelled not good enough to sell under their name.

    In conclusion he just said if you buy the tubes which are sold with the longest waranty, you will hear how your amp is supposed to sound.
  5. Yeah, the difference between tubes isnt that much, thats why i couldnt be more definate, it just seems to be missing something.

    And the difference between new and used shouldnt be noticable as long as each is working.
  6. fenderhutz

    fenderhutz Supporting Member

    Jan 28, 2007
    Harpers Ferry WV
    Uh, I could tell an immediate difference between J/J and Groove Tubes. Cleaner signal, warmer, more output.

  7. zenlowend


    Jan 26, 2008
    Which one's were Cleaner,Warmer, > output? ....details..details gentlemen (and laides if any come by).
  8. El-Bob

    El-Bob Supporting Member

    Oct 22, 2006
    Hamilton, ON
    hey, there's always a chance...
  9. I like the Tungsol 6550/ OLD Sovtek KT88. JJ KT88's will work, but they may run too hot if you drive them hard. New Chinese 6550's or KT88's are also great tubes. The biggest problem with modern tubes is consistency, so you should always buy them from a dealer who will warrant them. I use Triode Electronics Across the board, 6550 offerings of today are MUCH better overall quality than they have been in 20 years.
  10. Surly


    Feb 2, 2007
    South Florida
    From an electronics standpoint, KT88 and 6550 are the same part. I can't believe there would be such a difference in sound? Guess so!
  11. Do you have any experience with TAD (Tube Amp Doctor) tubes psycho ?
  12. Classically they are different.

    These days they may be more or less the same thing, but there are/were definate differences.
  13. FunkyFrosty


    May 28, 2006
    Well upon the advice of PBG and Mr. James Hart, I have Sovtek KT88's (new ones) and TungSol 6550's. I like the TungSols better.

    They are a very musical tube with an excellent break up, good tight low end and controllable highs (I'm not much into highs) but the excellent mid range characteristics are what makes this tube for me.........like I said very, very musical and well balanced when pushed, did I mention I like em alot??

    For Preamp tubes I have both NOS GE and a spare set of JJ's to be absolutley honest with you - I can't tell the difference.

    I also run TungSol and Electro Harmonix (preamp tubes) in my Peavey - the preamp tubes seem to make much more difference in this head (Peavey CL 400).
  14. Historically, yes and no. KT88's specs call for slightly higher heater current as well as more robust screen grid disappation. In modern practice, few KT88's actually differ from 6550's, which are all clones of the the 6550A, which mirrors a true KT88 except in heater current.

    They're specially produced and selected Chinese tubes. I have never encountered any of their 6550's or KT88's, but I'd expect them to be great tubes. TAD's have a good rep among people I trust.
  15. Sounds good, ive heard nothing but good things too. Just never had a chance to use em!
  16. Jerrold Tiers

    Jerrold Tiers

    Nov 14, 2003
    St Louis
    You can expect slight differences between tube makers. Each has a slight difference in mechanical construction, even for direct replacement tubes, and that is reflected in gain, etc, etc. In turn those factors make for the sound.

    Since the SVT was intended (after the original version) for the classic US made 6550, it should be best with them, or a close equivalent.

    The 6550 / KT88 differences are far less than the differences between other "pairs", for instance, the 6CA7 and the european similar tube EL34. The KT 88 and the 6550 are "both-way substituteable", but the 6CA7 subs for the EL34, not the reverse.

    These days, there are tubes made similarly, tubes that just happen to be close, tubes that would sub but the bottles are too fat and prevent it........ lots of choices. Most of the really bad subs and alternate manufacturers have dropped out, so most choices are OK.

    But, everyone seems to have bad runs, so a "good" maker now may be "bad" 6 months later.
  17. +1 on the 6CA7 subbing for EL34's & NOT the other way around. I wasted $200+ on a sextet of EL34's before knowing about Talkbass & finding out about JJ KT77's- which-BTW ARE a good replacement for EL34's-well were in MY case anyways!
  18. denton57

    denton57 Supporting Member

    Nov 1, 2005
    I, like FunkyFrosty, have NOS GE in the pre and TungSol 6550's. It sounds very, very, very good! Cant go wrong with the TungSols!
  19. cymbop


    Mar 1, 2006
    Durham, NC
    +1 on TungSols. Mine are original to my '74 SVT, and still kicking!
  20. zenlowend


    Jan 26, 2008
    Great reviews guys! I am ordering a replacement/backup set of Tung-sol's now. Just fyi: I found that Ruby Tubes has a 6550 Tung-Sol and they warranty them for 6mths. I'm calling on prices now. Someone chime in on things to look for when tubes are going out. And again, lets headoff the obvious...the amp won't work post. :rollno: But some of you guys that have experenced tube failure let us new-tubies know what you experenced and what to expect. This is an important issue to me and others with new(to us) vintage SVT's. Especially since the vintage SVT will run on 5 tubes and this is, I'm assuming, not good for it at all. So PSB and Jerrold, keep those opinions comming on anything you can think of with pertinance to the SVT. I think I can speak for all that own one when I say we love'em and don't want to fk em up making a "rookie" mistake or something we could have prevented with a little of your knowledge. Thanks again guys, your help here has already been invaluable.

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