12x7 tubes


I own a black ice audio dac that is connected to my CD player.Need advice on what 12x7 would be the best fit looking at Tungsram 12x7 and a GE 12x7 1950 long plate.My taste of music is classic rock and blues.

bigmac1963

Any of the old USA - made 12AX7’s (GE, Sylvania, Baldwin ...) are very good choices! I prefer them over any present day production. Old UK Mullards are really over-hyped and way too costly! I like the green ink Baldwins (made for use in the Baldwin organs).

I agree with Joe's Tube Lore that the USA - made 5751 is the best bang-for-buck choice!

Trying to match the right tubes with my system that  consist of a music fidelity m6si and dynaudio special forty’s speakers.

Brent Jessee is a great source ,

Tubemonger is another one ,  I replaced 3 RCA black plate 5751's 

with " slovakian " 12ax7's ( ecc803s ) in my phono preamp , Love Them .

The gain of a 5751 is 70% of a 12ax7 but you don't hear 70% less ,

the difference is about 1.5 dbs or a notch on you volume control .

I always buy my tubes through Brent Jessee - the tubes he recommends have always been a good upgrade to my gear...  Just got one a few weeks ago, in fact.

Brent Jessee recommend Tungsram 12x7 and GE 12x7 1950 USA long plate for my tube dac.Just looking for opinion on the tubes.

  +1 for Brent Jesse, read the tone descriptions they’re spot on. Next is what tone change is best for your system. After trying about a dozen brands of NOS tubes, I’m a huge Telefunken fan. That being said the Tungsram is a less expensive way to get the Tekefunken sound, then EI would be the next closest to Telefunken. I personally prefer the higher end German tubes, followed by the NOS American tubes. I’m not a fan of Mullard driver tubes as I find they put a vail over the music. However many people absolutely love them. Also Andy at Vintage Tube Service is excellent and I’ve also purchased from the Tube Museum although they’re a little pricy but great quality. Bottom line is you have to try them to find out. I spent about $3K answering that question 5-10 years ago. Happy Hunting, Mike B. 

I have a Black Ice Dac and have rolled many tubes.  I prefer a warmer tube so my favorites are Mullard f91/92 long plates late ‘50’s are just exceptional.  Pricey not overrated in my ears but the real deal. Close second are ‘50’s Rca long Black Plates are excellent.  Sylvania Gold Brand 5751 3 mica black plates are another pricey tube and excellent.  5751’s have  plenty of gain and I don’t notice a difference. I had early ‘60’s GE long gray plate (2 staple holes on each side of the gray plates) these don’t get much love but they are almost as good as the RCA black plates very nice durable tubes.. Telefunken’s were too clean and bright for me and feel they are overrated for their price..  They do work well in my phono pre though...good luck on your search.  It’s a fun journey.

Brent Jesse is an absolute prince among men. Every purchase I have made from him has been nothing short of an excellent experience. I can’t recommended him strongly enough!

having had the black ice/jolida dac (in chris johnson upgraded form), i would agree with the op in wanting a warmer smoother tube in its output stage

that said, i would add that that particular unit benefits greatly from bypassing the front panel volume control for improved sound quality... (if it is not needed for the headphone amp function, of course)

 I was in checking tubes out on BJ’s website and saw he had Ge/ Kentucky Radio pewter plates in stock.  You might want to inquire on those.  A little more cost than the Tungsram and Ge long gray plates.  They are exceptional ...as good as RCA black plates.  Probably the best Ge 12ax7.

Just order a pair of Tungsram 12x7 from Brent Jessee website. I will let you know how they sound with my system.

Add my vote for Brent Jesse. I have almost no tube knowledge and have made several purchases from him based on his advice. It has always been an improvement to my system and he is a pleasure to work with.

+1 Brent Jesse,patiently helped me upgrade tubes in my Herron phono and LTA MicroZotl….

Try vintage Amprex Bugle Boys. That’s what I use in the little black ice dac I have and the matching headphone amp. Clear, clean, lots of bass. Love them with this brand. 

I have had good luck with military spec sylvania NOS tubes. Actually many companies made NOS military spec tubes for the US and they are just awesome. RCA, GE, Philips, Raytheon. They usually have JAN in the name (Joint Army Navy). Jasonbourne52 is correct on the money. I have had really good sound from JAN tubes

@bigmac1963  Tungsram make great tubes I would expect you will be very happy with them.  I have some Tungsram 70’s 12at7’s in my raven amp and they are my best sounding 12at7.  Great dynamics, soundstage and clarity.  I have not heard their 12ax7’s. Brent is 👍 

It is senseless to talk about good and bad vacuum tubes without knowing the "house" sound of each brand which can vary according to production periods. If a tube seller doesnt ask specific details about your components as well question you regarding the desired sonic results they are doing you a disservice. Find someone that knows tubes as well as components and is more interested in finding out about you as a hobbyist than selling you what he has in stock. 

These forums are a great source of information, but avoid comments like you are fine with any such and such a 12AX7 and specify JAN tubes as being sonically different than civilian made tubes. Usually JAN tubes are the exact same internally as are the civilian versions. I think tubes made for medical devices or organs and perhaps other equipment have a better chance of sounding better than tubes for the military. Many comment on the quality of NOS or new production tubes with very little tube rolling experience or are rolling in equipment where minute changes cant be heard. Its interesting that some attest to the different sound of tubes but are also doubting or denying the affects of cables or other tweeks.

Every tube seller should tell you is that different tubes in different sections of just about every application do not affect the sound of the component equally even why they are of the same type and from the same mfgr. Whenever retubing a customer's power amp I usually start with the front end and then deal with the power tubes. My experience is that these driver type tubes always affected my tube amps more than changing the big guys.

FWIW: the 2 best more common types of old stock 12AX7s that I like are the Telefunken smooth plate and Holland made Philips Europe 12AX7s. Sometimes I will sell pairs of these to the same client for the same component. Mixing and matching 6SN7 pairs in the Atma-sphere amps is a great way to combine different sounding tubes in the same circuit.

 

NOS Telefunkens sound best, but are pricy. Try anything else to get your amp "on the air."

Tung sol gold pins are often recommended as a good upgrade for that component. I got rid of my black ice dac, had terrible hum issues....I got a border patrol dac, could not be happier.

Stellar Quality

Space and military applications required electronics that could operate reliably in extreme environments of high altitude, high acceleration/vibration and even space, where high levels of radiation are present. Incidentally, one of the reasons Russia continued to manufacture tubes was because these thermionic devices are immune to an electromagnetic pulse (EMP), the gamma ray burst that an atomic bomb releases upon exploding—Russian MIG jet fighters were equipped with tube circuitry in their radar systems so that an EMP would not interfere with onboard navigation systems.

Tube reliability was a real and ongoing concern for the US military. You may have seen the initials ‘JAN’ stamped on Philips N.O.S. tubes, which is an acronym for ‘Joint Army Navy’. These are ruggedised tubes manufactured for the military. During world War II the American military initiated a ‘ruggedisation’ program with aim of improving tube reliability in the field. For example, there was concern that delicate electronic comms equipment thrown around in the back of a jeep hurtling along a rock strewn dirt track might not fare too well. To remedy this perceived problem with reliability tubes were designed with shorter, stockier anodes, additional or thicker support micas and a very complex and elaborate tube numbering system evolved along with the numerous revisions of tubes [Getting the Most Out of Vacuum Tubes by Robert B. Tomer pages 72-75]. Reliability of electronics and tubes in military and space applications was of paramount importance.

True some tubes were designed from the ground up for military application, but most were not and were simply tested for shock and vibration by the factory for the military. The internals of these tubes were no different than the tubes released to the civilian market. Further, in most cases, audio considerations didnt exist for military applications, perhaps in some cases noise could be an issue but even this may be a stretch. Now if certain military design concerns necessitated change that influenced the overall tube market back in the day I cant comment to this. To assume that a JAN tube or more importantly a JAN designation indicates a better sounding tube would be a mistake.

audition__audio,

 

I agree with assuming that military spec product even matters in audio for the intended purpose that the product was made. You would better off reading and understanding say a JAN tube mil. specification before assuming that it would make the best for audio.

 

 BTW, are talking about 12AX7, AND NOT '12X7' CORRECT?

When I post information, it is about my experience with a product. I don't make blanket statements about what is good or bad. From the tubes I purchased and money I spent I found GE, Phillips and Sylvania NOS Jan tubes to sound very good. Not sure why my opinion would mot be as valid as the next. So my advice, in addition to my experience is that be careful what a salesperson tells you, often times they are very biased and arrogant with their assertions.

@boomerbillone 

NOS Telefunkens sound best, but are pricy. Try anything else to get your amp "on the air."

I like them, a lot. In terms of "pricey", I found four smooth plate that were Dynaco stamped, which costs much less than factory Telefunken stamped tubes. Got four for $380. No regrets for these great tubes.

As far as new, a similar sound signature as the Tele's,  but more grainy and not as smooth, is the Gold Lion gold pin tubes. You can get them for about $40 per.