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Groovetubes 12AX7M and ElectroHarmonix 12AX7EH review

Discussion in 'Amps and Cabs [BG]' started by LoveThatBass, Nov 26, 2004.

  1. I just got the tubes in and tried them out.
    Compared to the standard Groove tube 12AX7R.
    The 12AX7M is balsy, clear well defined low end, decent tone, low noise if shielded properly. They have more gain than the standard Groove tube.
    Having said that..the 12AX7EH is a close second. Good gain, clear, nice well defined low end but not quite the balsy low end of the 12AX7M..close though...Good tone.

    Having said that the 12AX7EH is a better buy at 1/3 the cost of the 12AX7M. Which will I use...12AX7M since I have it. The EH's will be my back up. I bought 2 of each while CE Distribution had them at 1/2 off till Christmas.
  2. I tried the Groove tubes 12AX7M too. Sounded as you described + not so good when breaking up. Didn't like the sound when I played harder and the bass growled accoustically. Sounded harsh with this tube. I since bought the Ei Elites 12AX7E which was just what I was looking for: Warmth, punch, clarity and breaks up nicely. A bit noisy but there's a gold plated version that should be more silent. Oh - and it's cheap too. Under 10 bucks.
  3. Carl-Anton , What amp do you have and does it have more than one 12AX7 tube? With the original tube or a Groove Tube 12AX7R I get preamp clipping on volume of 5. With the Groove Tube 12AX7M it does not clip until 7 or 8.
  4. BassGreaser


    Aug 22, 2002
    Austin, TX
    I just replace the AX7's in my bassman 135 with a pair of 12AX7EH's. I love the tone of these tubes, but is it common for them to very dim when the amp is running :meh:
  5. "but is it common for them to very dim when the amp is running"

    You mean the heater is very dim?
  6. BassGreaser


    Aug 22, 2002
    Austin, TX
    the tubes just aren't burning very brightly....sorry I don't know what the heater part of a tube is :p
  7. Some makes of tubes seem brighter than others
    If it sounds good I would not worry about it at all. The heater is the thin glowing redish orange strip in the center. That is what you are used to seeing glow. Some tubes hide the heater more than others.
  8. I use the SWR Bass750. One tube. It clips around 3 o'clock with not much difference as to which tube I use. With the Ei tube the clip is softer, more continious whereas the GT M seems to break up the sound, if you know what I mean.
  9. gfab333


    Mar 22, 2000
    Honolulu, Hawaii

    What does the M mean (in 12AX7M)? For example, I know that the R in the GT 12AX7R3 is for Russian.

    Thus far, I've tried a variety of 12AX7 / 12AT7 / 12AY7 tubes including GTs, RCA NOS, Mullard, and Ruby brands in my Eden WT-550. They each have their own tone character and gain levels. The differences are subtle but noticable to the discerning ear. For playing the R & B / funk / top 40 cover material that I typically do, I found the original stock Ruby tube that came with my amp to sound best as far as overall tone, warmth, articulate bottom-end, headroom, and punch. I'd like to try the EH and the GT 12AX7M as well. Thanks for the review!
  10. M is for Mullard copy. You are correct about the subtleties of the tubes.
    What I find is the EH is very quiet, good clarity and distinction.
    The 12AX7M has a bit better low end with plenty of punch with clarity and distinction. I hear the individual notes well defined.
  11. gfab333


    Mar 22, 2000
    Honolulu, Hawaii
    Well, I had to go out and buy one of these GT 12AX7M tubes to try out in my WT-550, just because of this thread.

    I brought it home and A/Bed it with the stock Ruby 12AX7A that comes in the Edens. At first impression, it has about the same volume as the stock Ruby, but it has slightly less low-end fullness. There also appears to be slightly more presence in the upper mids and treble ranges.

    I'm a bit disappointed in the low-end response, but I found that I can dial it back in with the amp's EQ.

    Can anyone comment on whether the tonal response of an amp will change after the tube as been running for awhile? if so, how many hours does it take to get the optimum tone out of the tube? I was thinking that maybe the low-end was lacking because the GT tube is brand new and needs to be burned-in?
  12. Finger Blister

    Finger Blister

    Jul 8, 2003
    I A/B'd my SWR with a GT12AXM against a
    • Ruby Tubes 12AX7 labeled Mesa
    • NOS long plate 12AX7, origin unknown
      (pulled from a Fender, when new by a Mesa Tech).
    • JAN Sylvania 5751
    • Stock SWR GT12AX7 Chinese

    Each tube produced different tones.

    Describing them is dicey at best,
    however I'm stupid enough to try...

    GT12AX7M - Focus on the Mids. With Mids breaking up first.
    Definitely a Guitar Amp tube.
    Has a voice that would appeal to r'n'r guitars.
    Ruby - had to roll back the highs. A little hissy.
    Fender 'blackface' - had sweet mids.
    JAN 5751 - was super low noise. Solid rump. Smooth highs.
    Stock SWR GT12AX7C - that 'SWR Sound.' A bit "high" in the Hi-Fi.
  13. So, your recommendation would be the JAN 5751?
    What brand?
  14. Finger Blister

    Finger Blister

    Jul 8, 2003
    Sylvania black plate JAN, JHS, etc...
    Sylvania Gold Brand black plate

    I use a Green Print JAN Sylvania.
    These usually cost less then a GTAX7M and will last much, much longer.

    • Suggestions are for clean tone,
      (dirt in the signal should be left to external devices designed for that purpose).
    • Claims made here are void if deaf, partially deaf, brain damaged, or retarded.
    • Not responsible for those unable to recognize good tone.

  15. Great info Finger Blister (and Kurt ;))

    Any links to places such tubes could be bought? Is the "5157 GE USA (JAN)" on this site one like yours? Would that tube give me the characteristics Kurt describes in his posts?

  16. Finger Blister

    Finger Blister

    Jul 8, 2003
    That'll do the trick.

    JAN and Made In The USA are the magic words.

  17. Thanks man :) I'll try one of those in time.