Tubes Asylum: REVIEW: Groove Tubes 12AX7-M Tubes by anumber1

Model:	12AX7-M
Category:	Tubes
Suggested Retail Price:	$21.95
Description:	Dual Triode signal tube
Manufacturer URL:	Not Available
Manufacturer URL:	Not Available

Review by anumber1 ( A ) on November 24, 2005 at 18:20:13
IP Address: 71.10.136.75

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for the 12AX7-M

While I am not a "NOS tube snob", I really haven't had a lot of positive experience with new production tubes. The JJ's and Sovetek tubes I have tried in the years past did not sound real good compared to what I had and simply did not last like even an 80's Phillips can.
I was lucky enough to get into vintage Hi-Fi in the early 90's. A good friend turned me on to the "tube sound", as I was familiar with low efficency speakers and lots of SS power to get them to rock. I was promptly hooked on relatively low power tube amps and horn speakers that were a bargain at the time. That stuff flat out sounded better than the kilo-buck Threshold Fet 2 pre, Nak PA-7 amp and Thiel CS-2 speakers that I was listening to.
In about 1991 I read an article in The Absolute Sound that was written by Steve of Angela Instruments that trumpeted the end of the "good stuff". In a mad panic I bought up as much NOS Tele, Mullard and Amprex that I could. I still have most of those tubes and have no real need to use the new production stuff. However, as of late I have decided that with all the positive posts I have read here about a few new production tubes, I owe it to myself to become at least a bit educated in the sound of the most popular and recommended brands of easily obtainable new stuff.
I have started with the Groove Tube 12AX7-M in my ARC SP3A-1 preamp.
In my experience with my ARC SP3A-1 pre amp, the tubes that matter the most are V1 in the phono section and V4 in the line stage. As long as V2 & V3 in the phono stage are in good condition and function properly they really don't impart a lot of sonic character like the V1 position does, the same goes for V5 & V6 in the line stage. I am using RCA 7058 tubes in V2,V3,V5 and V6 (These are sonicly neutral and long lasting tubes), JJ 12AX7's in the tone control section (which I don't use, so I only keep tubes that are electrically functional in those positions, I don't care one bit about micro phonics or the "sound" there).
I have the Groove Tube 12AX7-M's in the spots that count, V1 & V4 and have about 50 hrs on them now so they should be about "burned in" by now.
I have found that the GT 12AX7-M's is an exceptionally quiet tube with virtually no tube rush or micro phonics in my phono section., Even at high levels of gain it is very quiet and composed. Nice!
The GT 12AX7-M is touted as a Mullard copy and it does bear some resemblance to a short plate Mullard 12AX7. I am very familiar with the sound of a vintage Mullard in this pre amp as it has been my tube of choice when using my AT OC9ML/II cartridge for about a year now. The GT 12AX7-M's plate structure is similar to a vintage short plate Mullard and the tube seems well built with presicion stamped plates and well cut mica. The assembly is neat and it does not suffer from an "ugly", third world quality, sloppy build.
The GT 12AX7-M does not sound "just like" a Mullard, however it does share some of the classic Mullard traits. In my experience a vintage Mullard 12ax7 is a "darker", balanced sound than a Telefunken or Amperex with the Tele being the brightest, the Amprex kind of "between" the Tele and a Mullard. The 12AX7-M shares this with the vintage Mullard, however it is quite a nice sounding tube in its own right. Very full sounding, non-micro phonic and lush, yet very detailed and is capable of projecting a wide and deep sound stage. I find that I can easily live with the sound. Cool!
Before I installed the pair in my preamp I tested them on my Hickok model 6000 tube tester that was restored by the late Chris Haedt. Much to my surprise they tested close section to section and at respectable levels of transconductance. It has been my experience in the past that the new production tubes I have tested were marginal right out of the box in terms of transconductance and the sections always 20% to 50% apart. They simply never tested as strong as any NOS tube. The GT 12AX7-M does! Cool again!
I am glad a manufacturer has stepped up to the plate and delivered a tube that doesn't just rip off the name of a classic marque for marketing purposes, the GT 12AX7-M backs up it's hype with substance.
It is too early to tell what the service life will be and at the price they are not real cheap compared to the rest of the crop of new tubes. If they have even half the service life of a 60's Mullard then they will prove to be a bargain at the going rate of about $22.

Product Weakness: It doesn't sound exactly like a Mullard but is able to produce a very respectable tone in it's own right. Kind of expensive for a new production small signal tube.
Product Strengths: Good, ballanced sound and capable of living up to the hype of being marketed as a Mullard clone, even if it soen't really sound like a vintage Mullard.

Associated Equipment for this Review:
Amplifier:	Heath W5M monoblock tube amps, restored and modified with a revised power supply and a fixed biasing scheme
Preamplifier (or None if Integrated):	ARC SP3A-1
Sources (CDP/Turntable):	VPI Hw19MkIII TT, SME 309 tone arm, AT OC9ML/II cartridge, ALtec 4722 step up transformers
Speakers:	Altec Iconic (846A) two way horn speakers in a stylish Lane cabinet
Cables/Interconnects:	low end AQ type 4 speaker cable, Cardas time and space between pre and amps, AQ Lapis between TT and pre
Music Used (Genre/Selections):	50's-60's jazz, 60's blues and 60's-current rock-N-roll
Room Size (LxWxH):	12' x 13' x 11'
Room Comments/Treatments:	none
Time Period/Length of Audition:	2 weeks
Other (Power Conditioner etc.):	Tripp Lite surge strip
Type of Audition/Review:	Product Owner
Your System (if other than home audition):	http://cgi.audioasylum.com/systems/1612.html

Product Weakness:	It doesn't sound exactly like a Mullard but is able to produce a very respectable tone in it's own right. Kind of expensive for a new production small signal tube.
Product Strengths:	Good, ballanced sound and capable of living up to the hype of being marketed as a Mullard clone, even if it soen't really sound like a vintage Mullard.