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best 12AX7 for SWR 550x

Discussion in 'Amps and Cabs [BG]' started by lownote54, Mar 12, 2009.

  1. lownote54


    Mar 7, 2009
    just got an '02 SWR 550x. gonna have a tech go through it. not had a tube preamp in a long time. what's the recommended replacement 12AX7 these days?

  2. SpamBot


    Dec 25, 2008
    St. Paul, MN
    The Tung-Sols that MF sells are very clean. Go for about $15, too. Good deal.

    JJs are good if you like darker sounds. Usually for guitars, though.

    Telefunkens are the holy grail, but it's hard to find a good one for under $50, even if you look hard. You can get them NOS, but it'll set you back around $100.

    I'd go for the Tung-Sol.

    AVOID: Groove Tubes (They are rebranded Sovteks) and Sovteks. They are cheap, but you get what you pay for. Mesa and Ruby also rebrand.
  3. paganjack


    Dec 25, 2007
    Los Angeles, CA
    I've really enjoyed the JJs in my amp. I put the long plates in there, even though some say there are stability concerns. No problems for me and it sounds thick and bassy- just the way i like it!
  4. Red Planet

    Red Planet Banned SUSPENDED

    May 29, 2005
    I'm cranky in my old age.
    JJ's are great!

    Tung Sols dont last long enough for me.

    My favorite, (what I have in my SWR) two 1955 NOS Mullard ECC83 Long Plates. Yummy.:)
  5. edbass


    Nov 8, 2004
    I think it's totally a matter of personal preference. It's like asking which is best; Chocolate or Vanilla?
    The NOS European and American tubes are generally considered superior by the majority of tube-o-philes, but some of the current tubes aren't bad either.
    Have some fun, experiment until you find one (or more likely several) that you like!
    Barring factory defective ones, pre amp tubes, particularly the above described NOS ones, generally have a very long (often decades) service life.
  6. jimbilly


    Apr 19, 2006
    'used old stock' are most often great, a lot of that those had easy lives, if they test good they are most often good. I've got a 'pile' of used tubes, they all sound great. I'd go for used old stock over new chinese or soviet any day. Check your local area for Ham radio fest/swapmeets, last year I saw real tungsols for $8 (my friend bought those), all kinds of USA stuff for less than $15.
  7. mav


    Jun 10, 2003
    You should put in a 12AX7A not 12AX7 that's what SWR recomends.
  8. I like a 5751 instead of a 12AX7... a common swap for bass players and sounds really nice... it smooths the amp out a little and makes it more musical. I believe mine's a Phillips, and has been used in all my SWR amps.
  9. El Tookay

    El Tookay Supporting Member

    Sep 19, 2008
    Here's some info on several open-amp comparisons I've done over the years- that is, the cab in one place, same bass, same cable, but the amp opened up and swapping tubes, after the power cord is out, of course....

    Mesa 12AX7A- rich bottom, good mids, highs good but a bit stiff, really doesn't enhance the harmonics and overtones, but a good tube for straight-ahead rock or metal

    Philips JAN-spec 12AX7A- thick, almost muddy bottom, great mids, and a rolled-off top end- think Jaco tone. if i was doing exclusively fretless work, i'd have these in my amps

    Sovtek anything- give 'em to your guitar player. These shouldn't be used for bass, just a weak tone with no bottom end depth, a brittle top end, and boring mids.

    GT 7025- hard to find, but has a tight bottom, big mids like the Philips, and a smooth top end with nice harmonics. Can make even an SWR sound a bit SVT-ish. Sounded good in a red-fgaced 350 and 750 non-X.

    Ruby ECC83- don't tell anyone, but this is what Trace Elliot was using at the factory for the original SMX series, and for good reason, they sound good, almost into the range of JJ's. Downside to the Ruby is they don't last as long, and the Chinese stigma. Good tube.

    JJ ECC83S- big tight bottom that won't frazz with a low B, rich mids, and singing highs. This tube will bring out all the detail in your bass. Winner.

    As far a re-branded, GT's ECC83 is a JJ- just look at them, it's obvious, BUT- if you have a Stingray, this IS your tube. E-H are Sovtek's- same thing. The total package for any all-tube amp would be JJ's in the front end, and either JJ's or Winged C's in the back. A friend of mine has this set-up in both his Marshall Superbass and Marshall Major, and using either of his amps with a G&L El Toro is mind-blowing. FWIW, i use a JJ ECC83S in my Shuttle 6.0. Total amp GAS killer.

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