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Preamp tube questions

Discussion in 'Amps and Cabs [BG]' started by wraub, Jun 27, 2012.


  1. wraub

    wraub

    Apr 9, 2004
    ennui, az
    previated devert
    Greetings.
    I have an older SWR Grand Prix (pre-Fender), which uses a
    12AX7 tube. I got it with a GT tube in there (possibly the original), but switched to a NOS 5751 tube for a mellower sound, albeit with less output. That went microphonic a while back, so I am back with the GT.

    Between the probable age and the different output (hotter, less smooth and "creamy, if you dig), thinking a change may be coming soon.
    Any other suggestions for a "better" replacement?

    Not especially brand picky, and NOS is fine if not too crazy expensive. I liked the sound of the 5751, but didn't like the lower output for some of my gigs. Other 12AX7 tubes would likely sound pretty similar, but am curious about potential differences in tone/output.
    Relatively new to the world of tube possibilities.

    TIA...


    wraub
     
  2. Muckaluck

    Muckaluck

    Oct 11, 2005
    Whitby, Ontario
    I've had good luck with NOS RCA 12AX7s. I have them in my Orange AD200b and they take away the crunch sound that many new tubes give and instead bring a warm, mellow breakup into preamp distortion. I think mine are grey plates.
     
  3. wraub

    wraub

    Apr 9, 2004
    ennui, az
    previated devert
    Good info, thanks.

    wraub
     
  4. pacojas

    pacojas "FYYA BUN"

    Oct 11, 2009
    MEXICANADAMERICA
    Shuguang 12AX7-C9 or the modern equivalent 12AX7B!:hyper:

    said to be the highest gain pre tube in this category. very musical with an almost 3D bloom to each note. i recently R&R'd a 12AX7-EHX with this model and it blew me away. i think the crystal clear harmonics were the most telling difference. they cost around $15-20.
     
  5. wraub

    wraub

    Apr 9, 2004
    ennui, az
    previated devert
    Thanks for that, pacojas. That's just what I needed.

    Anyone else have possibilities/favorites?

    wraub
     
  6. Raytheon 12AX7s are pretty well rounded tubes, and not too expensive if they're not NOS. They were used in Lowrey organs, so if you search ebay for Lowrey 12ax7 you may find a Raytheon tube, relabeled for Lowrey, for less money. RCAs are nice, especially the black plates.

    Usually if you study a certain brand of tube's markings you can tell when they are relabeled for another company. For instance, I buy a fair amount of RCA 12au7s, but if I buy them labeled as Conn (organ) tubes they are cheaper, even though I know they are RCAs by the glass etching and tube structure.

    Edit- the above mentioned tubes can be found on ebay from $8 and up buy it now, plus shipping.
     
  7. dave_kts

    dave_kts

    Jan 17, 2008
    Try out an Ei ecc83 from yugoslavia.. they seem to be a little steep tho. I have one and was my favorite out of an amparex, an RCA black plate, a GE and chinese new production. Bought a used Art tube EQ from a member here and this tube came in it. Sounded nice in a Peavey max tube pre and sounds great in my Mesa bass 400+. Even tho its a long plate I've practiced and gigged awile with it and still not microphonic.
    Gain is slightly less that chinese current tubes, a smoother high-midrange, (less bite) nice punch and controlled low end
     
  8. username1

    username1

    Dec 28, 2005
    alberta canada
    I have done alot of tube rolling in my amps and my favorite so far is a new issue gold lion. They aren't cheap, I think about $45 but they sound great and have decent gain.
     
  9. wraub

    wraub

    Apr 9, 2004
    ennui, az
    previated devert
    Cool, thanks to all.
    Trying to flip some gear so I can get new tubage, but for now I'm still looking for suggestions. Plenty of good ones here so far. Anyone else?

    I know the Grand Prix isn't as boutiquey cool as some others, but based on the design, anything that'll maximize what the GP has to offer?


    wraub
     
  10. chadds

    chadds

    Mar 18, 2000
    New Tung Sol. They can be bad. Check for a return policy. When they are good they are clear and airy. Sylvanias, little known vintage secret. Rich and lush. Can be dark to some folk but some likey.
     
  11. LiquidMidnight

    LiquidMidnight

    Dec 25, 2000
    I find (new) Mullards to be pretty creamy and mellow if you want to try a 12AX7.
     
  12. Randyt

    Randyt RAAPT Custom Wood Productions

    Jul 21, 2010
    Barrie, Canada
    im using the Northern Electric 12ax7....and they are fantastic
     
  13. BurningSkies

    BurningSkies CRAZY BALDHEAD Supporting Member

    Feb 20, 2005
    Syracuse NY
    Endorsing artist: Dingwall Guitars
    Is that one of the new reissue NE tubes? Or do you have an old one?
     
  14. chadds

    chadds

    Mar 18, 2000
    I enjoyed that very much thanks!
    It's astute of you to point out the difference between the sonic needs of bassists being distinct from guitarists and hifi users.
     
  15. Glad you liked it. I had fun. Yeah, also from the reliability perspective, I really like over-engineered Cold War military tubes. They can take the rough vibes of being played on top of a bass cab.
     
  16. For cheaper NOS, I like the Tungsram ECC83 (12AX7) from Hungary. Great bang for the buck, just bought a balanced used 100% quad in boxes off eBay for $69, and I was the only bidder. Also bought 4 NOS Tungsram ECC81 (12AT7) for $20, no opposing bids. These ECC codes are Euro. Lots of Euro dealers won't bother putting the US equivalent designation in the auction title or body, so you might well be the only American bidder getting these wonderful deals. Shoot, someone might even advertise a 7025 without mentioning 12AX7. Here's a chart of tube designations and subs so you can build a useful eBay search string: http://www.vacuumtubes.com/12ax7.html

    Another review of the Tungsram: http://www.tubeman.com/item11.htm
     
  17. I installed JJ ECC83s in my pre-amp. Nothing I can put my finger on but I LIKED them in there.
     

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