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  • NOS/used tubes...questions on them.

    I have tried RCA 12AX7 and enjoyed them in almost everything-got in a 1964 Bassman that was given to me.  Many months back I found NOS Westinghouse 12AT7s and found they mellowed out my amps, and then got some NOS Sylvania 12AV7s and found they really mellow out my Vox AC4TV stack.  

    I recently got some used but "tested" (on a machine that looked as old as the tubes) EL84s.  1 RCA, and 1 Mullard "International."  Up until this point I was using the stock Sovtek in my AC4.  I tried the RCA and it had good headroom and punch, but when distorted it seemed to have a strange decay/fuzz.  The Mullard seemed to have a tiny amount of this but sounded much smoother and like my Sovtek but without the dullness.  

     

    ANYWAY the point is, can a tube "test" good and still sound kinda weird/crappy?  I know a place that has many NOS/used tubes that can be tested- somewhat- but I guess are some brands better than other as far as chance of getting a good "used" one? 

    Guitar: PRS CE-22 wirds, PRS Starla LTD, PRS 408 MT Gibson SG Classic, Classic Vibe 50s Strat. Trem-O-Verb head, Blonde Bassman into Recto Standard Slant 4x12, Vox AC4TVH and matching Cab.HCBF Warwick Owner's ClubWarwick Streamer Standard 4 string, or Ibanez SR405, SWR Grand Prix into SF800 power amp into SWR Twelve Stack.

  • #2

    c_corie wrote:

    I have tried RCA 12AX7 and enjoyed them in almost everything-got in a 1964 Bassman that was given to me.  Many months back I found NOS Westinghouse 12AT7s and found they mellowed out my amps, and then got some NOS Sylvania 12AV7s and found they really mellow out my Vox AC4TV stack.  

    I recently got some used but "tested" (on a machine that looked as old as the tubes) EL84s.  1 RCA, and 1 Mullard "International."  Up until this point I was using the stock Sovtek in my AC4.  I tried the RCA and it had good headroom and punch, but when distorted it seemed to have a strange decay/fuzz.  The Mullard seemed to have a tiny amount of this but sounded much smoother and like my Sovtek but without the dullness.  

     

    ANYWAY the point is, can a tube "test" good and still sound kinda weird/crappy?  I know a place that has many NOS/used tubes that can be tested- somewhat- but I guess are some brands better than other as far as chance of getting a good "used" one? 


    Yes.

    I've gone through a lot, especially preamp tubes, that test great but are microphonic or have pops and strange noises. They can also be ok in low gain amps but show flaws in a Boogie or other high gainer.

    Only way to be sure, IMO, is to test then in the amp.

    I have lots of old Mullard EL-84, they should work and decay like any other but sound a whole lot better.

    Sounds like they're starting to go bad, but without torturing them myself I can't be sure.  Also watch to be sure the plates aren't glowing red, that's bad and can melt the amp.

     

    Also a lot of them that are branded Westinghouse or a lot of others were made by a different company, lots of mullards and Amperex out there with different labels on them, the number codes and symbols on them will tell who made them

    CHAO AB ORDO

    Comment


    • guitarcapo
      guitarcapo commented
      Editing a comment

      The "mellowing out" you are getting with those preamp tubes (that are not 12AX7) probably has more to do with their reduced gain factor than the brand or previous wear.

      As for power tubes, it's anybody's guess how they are going to sound overdriven....new or used. Tubes were made NOT to distort, so a tube that distorts one way or another has little bearing on whether it's a "good" tube.

       

      BTe I believe Mullard Internationals were made in Japan. Not sure though.


  • #3
    I got a 12AX7 that says Magnavox on it and "made in Great Britan". Does that mean its a Mullard just rebranded? Also I got a 6EU7 made by Zenith and a 6EU7 branded RCA

    Comment


    • chuckgp
      chuckgp commented
      Editing a comment

      Mr.scary96 wrote:
      I got a 12AX7 that says Magnavox on it and "made in Great Britan". Does that mean its a Mullard just rebranded? Also I got a 6EU7 made by Zenith and a 6EU7 branded RCA

      Probably.  There are code letters, numbers, and symbols on the tubes, other than the brand name, that tell what the tube really is.



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