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Need Help Picking Out Correct 6550's

Discussion in 'Amps and Cabs [BG]' started by jeffgnr90, Jan 2, 2016.

  1. jeffgnr90


    Aug 4, 2011
    A while back i had a pair of tubes fail on me, so I went through amazon and replaced the pair with these..

    Amazon.com: Groove Tubes GT-6550-RD-R10 Duet Matched Power Tubes: Musical Instruments

    I now suspect that the remaining 4 tubes are on their way out, and i'm looking to purchase a quartet or maybe a sextet through tubestore or amazon. I saw a quartet of these on Amazon and I'm wondering if these will be a good match for the other 2 tubes i replaced earlier, or if I should just bite the bullet and purchase a sextet from tubestore.


    Also, my amp has an autobias.

    Any insight into this?
  2. B-string

    B-string Supporting Member

    If the pics are correct it is the Russian 6550 (likely a Sovtek of some model) Groove Tubes has rebranded. Ask for the "High" as your previous pair was a #10 matching number (GT's numbering system). Or you can order a sextet from someone like 6550WE, Sovtek.
    jeffgnr90 likes this.
  3. jeffgnr90


    Aug 4, 2011
    awesome, thanks for the quick reply bstring. What's the difference between 6550-RD and 6550-R? is that just rebranding as you said?
  4. B-string

    B-string Supporting Member

    Yes Groove Tubes is and has always been a re-brander. The R after the tube model (6550) is the country of origin. R is Russian, C is China, S is Slovak. The "D" may have just been Russian Duet for ordering.
    Last edited: Jan 2, 2016
    jeffgnr90 likes this.
  5. jeffgnr90


    Aug 4, 2011
  6. jastacey


    Feb 8, 2009
    I would suggest getting a set of 6550 from T&C Tubes, they sell the Sovtek brand and tthey will test, match & burn in, the tubes at the voltages the amp runs at, here's a link tctubes.com vintage vacuum tubes
    jeffgnr90 likes this.
  7. jeffgnr90


    Aug 4, 2011
    I'll definitely check them out, thanks!
  8. Primary

    Primary TB Assistant

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