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ANOTHER tube thread-NOS 6550s or new

Discussion in 'Amps and Cabs [BG]' started by poorbassist15, Aug 11, 2019.


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  1. Wasnex

    Wasnex

    Dec 25, 2011
    If the amp is a G60VR it's rumored to have weak transformers. If the tubes are running hot, it's probably best to have the amp looked at.

    Pignose G60VR | Warehouse Guitar Speakers
     
  2. It's a B100V. The combo one, with the chassis removed and put in a head. It got a clean bill of health with weaker Philips 6l6s and he advised a retube and recommended jjs. After the replacement of the redplating one, it runs fine and has for years, including hard use because it sounds great in overdrive. However it also doesn't have 700v on the plates so I feel if a KT88 runs away it will be worse.
     
    Wasnex likes this.
  3. cerrem

    cerrem

    Apr 4, 2006
    San Diego
    I have been using the JJ KT88 tubes in many SVT heads with the least issues over other tube makers...
    The older Winged C 6550 were pretty good...
     
    Wasnex likes this.
  4. Nighttrain1127

    Nighttrain1127 Supporting Member

    Nov 27, 2004
    Near Worcester MA
    I have had good luck with JJ's from Eurotubes in my 70 and 74 SVT's Both retubed about 4 years ago and no Issues with any of them with moderate use Probably 10 hours on each per week since retube.
     
    rodl2005 and Wasnex like this.
  5. I've had good luck with Sovtek 6550's. The last 6550's I bought were Tung Sols as I have read many good reviews for tone and reliability, but I have very few hours on mine. Always buy my power tubes from Tube Depot with their burn in process and matching (Maxi Matcher).

    The SVT 2 pro i have that supposedly came from Gene Simmons (labeled as #2 head) had Sovteks that measured fairly high on my tester. No clue on their age, but they sound great.
     
    jdubbass38 and Wasnex like this.
  6. jastacey

    jastacey

    Feb 8, 2009
    Houston,Tx
    I have a set of Sovtek 6550's in my SVT-CL, it's been several years now, and haven't had issues with them, ordered them from T&C tubes, I also have a Super Bassman 300, and I believe they are loaded with the Fender branded, Sovtek 6650's, haven't had any issues, with that amp either, I tend to use the SB more, that's my current experience, using the Sovtek 6550 tubes
     
    rodl2005 and Wasnex like this.
  7. Same. Super Bassman with the stock Sovtek 6550s in since 2012 . No probs so far.
    I run it with a small cab often, so it gets into power tube drive, so, it ain't as if it never gets run fairly hard.
     
    jdubbass38 likes this.
  8. So I spoke with Doug at doug's tubes, and he actually advised against kt88s in an svt and recommended the ruby 6550a copy. Said they wont have enough space to cool in an svt.
     
    JimmyM and Wasnex like this.
  9. Tubedepot and thetubestore both recommend tung sols so it sounds like the dealers actively advise against kt88s.
     
    JimmyM likes this.
  10. JimmyM

    JimmyM Supporting Member

    Apr 11, 2005
    Apopka, FL
    Endorsing: Ampeg Amps, EMG Pickups
    I don't see the point of re-engineering the SVT myself.
     
    agedhorse likes this.
  11. Wasnex

    Wasnex

    Dec 25, 2011
    I don't think I would be concerned about this with a vintage amp. The tubes are side by side and the fans are so aggro that I would be very surprised if overheating is a problem. My SVT's are both vintage.

    Modern SVTs pack the tubes a bit tighter though, so perhaps there is some valid concern with running KT88s here. I believe this is @JimmyM 's amp.
    [​IMG]
    There are a fair amount of threads where people talk about running KT88s in modern amps as well.


    The Ruby's you bought are well respected and one of the types I recommended :thumbsup:.
     
    Last edited: Aug 22, 2019 at 2:29 PM
    JimmyM likes this.
  12. JimmyM

    JimmyM Supporting Member

    Apr 11, 2005
    Apopka, FL
    Endorsing: Ampeg Amps, EMG Pickups
    You are correct! I have the only Heritage SVT-CL factory equipped with a Heyboer output transformer, and mine was the very first to use those low profile Bircher style power tube clamps! Honestly, though, after comparing a stock HSVT-CL to mine, if I had it to do over again, I'd have skipped the Heyboer :D They're a great company with very reasonable prices and high quality work, but I couldn't hear a lick of difference.
     
    Wasnex likes this.
  13. Well, I've not purchased just yet, but it'll probably be jj 6550s or tung sols again. They did sound good when they were working. I want a little more fatness in the sound so I've heard that jjs tend to do that
     
    JimmyM likes this.
  14. Wasnex

    Wasnex

    Dec 25, 2011

    Just for fun:
    [​IMG]
    [​IMG]
    [​IMG]
    [​IMG]
    [​IMG][​IMG]

    Notice the JJ 6550 is the only one that is drastically smaller than the others. I would say the JJ KT88 is the largest by a slight margin.

    The VA6550A should be the same tube as the Ruby 6550A. Check the image here: Ruby 6550A-STR

    I included the EHX 6550 and KT88 to show that they appear virtually identical. I strongly advise against using either EHX tubes in high voltage applications based upon person experience with them being extremely unreliable.

    The images all came from Antique Electronic Supply
     
  15. Do you recommend the valve art? This amp has quite strong highs, I had assumed the jjs muffle that a bit.
     
  16. It appears they are. As are the ruby 6550a-str
     
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  17. Wasnex

    Wasnex

    Dec 25, 2011
    I haven't compared all of these tubes directly. Mostly I have done research on what current production tubes are reliable and which ones people seem to bag on a lot for problems. This is basically from reading lots and lots of threads in various only communities, so it is by no means scientific. I have done the market research because I have amps running GEs, Sylvanias, and Winged Cs, which unfortunately are all out of production.

    The only current production 6550s I have any direct experience with are JJs, and I don't consider them dark or muffled.

    As I mentioned the Valve Art should be the same tube as the Ruby 6550A, but you don't get Ruby's testing and matching.

    Describing an SVT as having "strong highs" seems a bit odd to me. What preamp tubes are you running?
     
    D.M.N. likes this.
  18. Ge longplate 12ax7 in v1, some old sino 12ax7s for the eq recovery stage and phase inverter, and 2 Jan Philips 12au7s for the cathode followers.
     
    Wasnex likes this.

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