Replacement 12ax7 output tube for old DAC

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jandrews

Replacement 12ax7 output tube for old DAC
« on: 23 Mar 2022, 10:12 pm »
Greetings,

My 28 year old C.A.L. dac has a single 12ax7 tube in it as an output stage.  I believe it needs to be replaced.
I'm not 100% sure it's the original or not.  But ...as far as symptoms , sometimes intermittently the decay of certain notes or chords in the music being played sound like they are fluttering or choppy.  Hard to describe.   The issue is not my amplifier after the dac.
So...I'm curious what folks think is a good choice for a 12ax7 to be used as an output stage.   I don't think gain is of primary importance here.  3-D imaging and controlled bass would be most ideal to me.  I don't think a NOS tube is really necessary for me for this purpose ...looking at new production Tung-sol or gold lion 12ax7's ...but would love to hear opinions.
Thank you
JS

WGH

Re: Replacement 12ax7 output tube for old DAC
« Reply #1 on: 23 Mar 2022, 10:46 pm »
What is the old tube? Do you like the sound or want something different?

Jim McShane has a nice selection plus he is one of the good guys. I recently bought matched pairs of CV4024/12AT7 Mullard and B749/12AU7 Genalex from him. I use the Sovtek 12AX7LPS in my phono preamp and they are silent.
http://www.mcshanedesign.net/tubes.htm


Genalex Gold Lion B759/ECC83/12AX7 reissues! Tis is a great tube - warm, excellent (one customer described it
as "sublime!") midrange and super soundstaging. The latest production tubes are much quieter, I can now recommend it for
phono and or other noise sensitive stages with its low hum spiral wound heater. $44.50 ea., $89.50/pair.

Mullard reissue 12AX7 long plates! Another new production tube getting excellent reviews! One more fine quality
tube, and just $18.50 ea. or $39.50/pair. As usual, my price includes tests you pay extra for from some other vendors! I have
good stock on hand, ready to ship!

Mullard reissue CV4004/12AX7 short plates! Initial reports are quite positive and based on what I've seen from
the Mullard reissue line so far I expect it to be an excellent tube - and more microphonics resistant due to the tube's short
plates (as compared to the long plate Mullard). Be sure to order the CV4004 if you want the short plate tube! If
you order the 12AX7 you'll get a long plate! $21.50 ea., $43.50/matched pair.

*Sovtek 12AX7LPS tubes, very low noise spiral filaments, checked for good section-to-section match, $17.75 ea.,
or $36.75 per matched pair; quads (if available - these are VERY rarely needed) are $74.50. For specially selected tubes
(for Aesthetix and other hi gain/noise sensitive gear) selected pairs (when available) are $59.50. These are great for sockets
where a good quiet tube is needed, and the tone is top shelf. My tube of choice for Citation phono stages! Very limited stock!

12AX7 Tung-Sol reissue. Many very good reports are coming in on this tube! It's punchy, has extended treble and
excellent bass, and is nice and quiet. $18.50 ea.; matched pairs are $37.50/pair.

12AX7/ECC803S Tung-Sol gold pin. Get improved socket contact with this tube. If you have any wear on the socket
the extra thickness of the plating and the corrosion resistance and good connectivity of the gold pins can help. $32.50 ea.,
matched pairs are $65.50/pair.

5751 Tung-Sol reissue; these have received many very positive reviews and they test VERY quiet!
The NOS is about gone - especially if you need matched tubes - so here's a terrific new 5751 at a great price, $24.50 ea.
or $49.50/matched pair. Remember, my price includes testing others don't do or you pay extra for!!


AllynW

Re: Replacement 12ax7 output tube for old DAC
« Reply #2 on: 23 Mar 2022, 11:16 pm »
I just retubed my C.A.L. Alpha with GL-12AX7 because I started using it again.  Heck, it sounds better than it has for years.

jandrews

Re: Replacement 12ax7 output tube for old DAC
« Reply #3 on: 23 Mar 2022, 11:24 pm »
Thanks WGH
Great to hear AllynW, by GL-12ax7 you mean Gold Lion reissue?
FYI my C.A.L. is the sigma ii

JakeJ

Re: Replacement 12ax7 output tube for old DAC
« Reply #4 on: 24 Mar 2022, 12:12 pm »
Excellent recs, gentlemen.  I will simply add that the new production tubes today are great quality for a reasonable price.  Are NOS tubes better?  Yes but they cost three to five times as much which is way above my pay grade.  If dealing on eBay take great care to vet the seller well so you don't get burned.  (Pun intended)
« Last Edit: 27 Mar 2022, 12:39 pm by JakeJ »

Dieterle Tool

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Re: Replacement 12ax7 output tube for old DAC
« Reply #5 on: 24 Mar 2022, 01:17 pm »
I don't think you can go wrong with the new Mullard's, particularly in pairing with streaming devices. Their reasonable price makes them even more attractive.

-Dieter

gene9p

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Re: Replacement 12ax7 output tube for old DAC
« Reply #6 on: 7 Apr 2022, 01:51 pm »
5751 Tung-Sol reissue; these have received many very positive reviews and they test VERY quiet!
The NOS is about gone - especially if you need matched tubes - so here's a terrific new 5751 at a great price, $24.50 ea.
or $49.50/matched pair. Remember, my price includes testing others don't do or you pay extra for!!

I have a Pair of the NOS Tung-sol that I am using in my Mac C2300 tube preamp....great!. I also like the NOS JAN GE 5751 tubes that I also have from a few years ago when I bought a Mac C220 tube preamp.

The best new tubes on the market right now for your set up is the Genalex Gold Lion 12x7 gold pins

jandrews

Re: Replacement 12ax7 output tube for old DAC
« Reply #7 on: 7 Apr 2022, 02:39 pm »
Thanks gene9p,
I ended up purchasing a new gold lion gold pin from a list member here last week.
It’s in my 29 year old DAC now, and sounding great. 
Much improved from what was previously installed. Spatially , the tube seems to add quite a bit , and the sense of texture especially to vocals is pronounced.
JS

AllynW

Re: Replacement 12ax7 output tube for old DAC
« Reply #8 on: 7 Apr 2022, 05:34 pm »
I use Gold Lion 12AX7's in my CAL Alpha.