12AX7 tubes- the best sounding, the rare, and the ugly

First there are 5 different names for 12AX7 tubes 12AX7, 12AX7A, 7025, 5751WA, ECC83.
The 12AX7 is clearly the OG (original) version of this tube. This market is its all 12AX7's turf.

Almost Extinict like the dinosaurs

The 12AX7A- The majority came out around 1960's and have greyplates. RCA and GE made these for electronic organ manafactuers and the organ brand name can be found on the actually tube label in some cases. The 12AX7WA was the version made for the U.S. military and there is also a WB not to be confused with the Warner Brothers and WC. The W was military code A,B,C marked the later versions. The new peoductions of Russian and Chinese tubes have WX,WB, or WC codes on them, this doesnt mean jack so dont be fooled.

the ECC83- The European version of 12AX7 its marykate to ashley olsen if you will because they are identical. The ones in demand are Telefunken, Amperex, Mullard, and Siemens. Even more scarce in population are German made Valvo and early Holland made Philips Miniwatt and Philips "SQ." Out of Telefunken ECC83 you want to look for the smoothplate or otherwise known as the flatplate versions. Some of these Telefunkens on the market are also marked as Fisher or Dynaco which doesnt matter they are the same they were just made for OEM applications. Real Amperex and Mullard tubes have a pair of alpha numeric dates codes printed in dark grey near the bottom of the tube and may help in telling what brand a tube is if the logo is worn away. The rarest of all of these are the Amperex buggle boys with the treble clef music symbol next to the buggle boy image and or just the buggle boys are extremely rare. Older Mullard logos that look like a shield are the rarest of the Mullard exspecially with BVA written under it. Also keep your eyes peeled for Mullard 10m series of these tubes in pimp purple and gold boxes. They were screened for 10,000 hour heater life, matching internal triodes, and low noise. The Master series has gold plated pins and the Concert Series has the standard pins. They are very scarce unfortunately high in price as well these days . Mullard and Amperex earliest versions from the 1950's of ECC83 came in square and D getters which is when the little halo inside the tube is actually square or shaped like a D a fit to make the finest sounds. Watch out for fakes of the AmperexBugleboys and Telefunken smoothplates. You'll know they are fake if the label doesnt wash or wipe off, normally these labels will come off as easy as the slightest brush of your finger across them. The buggleboys will have buggleboy on the cartoon tube on the box and sometimes the Telefunken will have gold pins when they are fake.

7025- This was an industrilal version, that has a spiral wound filament. Can be good for hi-fi equipment because they have very low noise but so does premium brands and blackplates.

ECC803S, E83CC, E803CC-The S stands for special meaning a special european version of ECC83. What is so special about them? Well they were screened for low noise and matching internal triode elements. Although European this has been made into a 12AX7WA military type. Very rare in the USA but can be easiest to come across the rare Telefunken and Siemens versions.

5751- This was usually made for the U.S. Military. If you live in a animal house or your significant other likes to throw your collectiables when they are mad at you these are just the tube for you because they tend to be more durable and can take drops to the floor, not that I'd suggest one. Not just to be used in a game of hot potato they are also great hifi tubes that tend to be very close to 12AX7 just with lower gain that reduces noise and microphonics. The earlier versions which always seem to get more attention have extra support rods and an extra mica spacer on top of the plate structure as well as blackplates to contribute to low microphonics. The grey plate versions also come with the same genes and carry triple mica as well. GE came out with a series for broadcasting use as well as RCA which called them the "Command" series for all of you training your deaf jack russell terriors.
　
It all comes down to the sound!

Telefunken and Siemens- Breath taking open air, t-rex large soundstage, great for adding some spunk to mono apps, the midrange is like it just got ran over by a steamroller it's so flat, and a on point bass . They can be found on the brightside though.
Rough economy hint for cutting corners when moneys tight- Telefunken ribbed plates were made in the same era and factory as smoothplates and have very very discreet differences. You can also find Siemens Valvo and Lorenz for cheaper.

Amperex, Philips, Mazda, & other Holland/France New old stock tubes- does a balance of justice with a clean airy top end, the midrange has warmth, and again the bass is on it's A game. Recomended for musical uses of hi-fi equipment. Unusual for alot of European tubes these break up great when overdriven in guitar amps. French Mazda combines some of the more warm sound you get from amperex with the air you can get in a Telefunken with a dynamic punch in the sound.
Economy tip- The Philip Miniwatt series were made in the same Holland factories that Amperex buggleboy tubes were made in an can work for an solid alternative because they have identical insides, have the same factory codes, and the obvious sound similar.

Mullard & Genalex-warm midrange, the top end could be described as milky, specialize in making human voices exspecially female voices feel as if there was a ghost standing next to you singing, definately has razor sharp detail.

RCA, Raytheon, GE, Sylvania, & more USA made NOS-I recomend the RCA, Raytheon, and Sylvania blackplates out of this catergory because they are very musical and have a sparkle of air at the top end, warm midrange, and slamming bass. The RCA are great for guitar amps even in greyplates and longplates. I have heard GE greyplates called "all around nice guys" too bad nice guys finish last.