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My S-W(ubbleyou)-R preamp tube swap

Discussion in 'Amps and Cabs [BG]' started by MooseLumps, Feb 18, 2008.


  1. MooseLumps

    MooseLumps Supporting Member

    Nov 4, 2007
    Portland
    So, i have a 96 era SM-400s with the ORIGINAL GT-12AX7. I decided that mebbe i'll take my tech's advice and swap tubes. afterall, it's only been 12 years. I walked out of the music store with a GT-12AX7-R for 21 bucks. I A/b ed them and i will post a review after further testing, but after a 20 min trial, these are my impressions.
    1. warmer mids. I wouldn't go as far as to say it sounds any bigger or anything... i think it's slightly (perception) louder because of it... we will see how i feel tomorrow.

    2. much clearer. I have a whole new appreciation for harmonics... even my girlfriend could hear a marked diffrence.

    3. increased top end definition... similar to above except for notes stay... sassy now on the top end... previously they tended to get a little sterile.

    4. I fell that the tube is slightly quicker to compress than the old tube... I hate to say it but i do like it better that way.

    all in all, i'm gonna leave it in for the time being. i like the character. it has more voice than some other preamp tubes, so it may not be your thing.
     
  2. Eminor3rd

    Eminor3rd BLAAAAARRGGHH!!

    Feb 10, 2008
    NYC
    Thanks for the info!
     
  3. MooseLumps

    MooseLumps Supporting Member

    Nov 4, 2007
    Portland
    Well after some more time fighting with this tube, I have determined that it has it's merits and place, but it's not a universal solution. It has a very strong voice for a pre-amp tube. It really warms up the mids and highs, gives them booty and voice. It increased my top end definition, but unfortunatly, it reduces my lows around 100 hz. The fundamentals are weaker for the lower strings. it sounds fabulous on chords on my six string, but my cort curbow needs a bump to the bass side of the onboard eq and still sounds relatively wimpy. i'm not going to switch out to the old tube, but i'll probably get a mullard copy and try that. i really like the tube for a lot of things, but I cannot forgive it for hurting my sub-lows. however, if you want to hear your harmonics ring out twice as loud, give this tube a run. And for the record, the low reduction is less than the increase in the highs, especially the harmonics... I would use this tube for piccolo bass in a heartbeat.
     
  4. Rather than going out and buying tubes to try- see if you can hit up a guitar playin' buddy and swap out individual 12ax7s...

    I do know that the stock Ruby or whatever is in my SWR seems to respond better for what I want than any of the other tubes I've pulled out of my guitar amps- to include original Mullard, RCA and Telefunken.

    Really listen to what the tube is doing, rather than being wowed by having an Amperex that costs more than the amp.
     
  5. I eventually replaced the original tube in my sm400s with a JAN Phillips 12AX7WA. Smooth and creamy... After putting Tung-Sols in my Aguilar db 359 I'm curious to hear what one would do in the SWR...
     

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