What Are The Best 12AT7's and 12AX7's?

What tubes are in there now? I am a Mullard man, so I always recommend the Mullards for most applications. I get these from Kevin at Upscale Audio.

http://www.upscaleaudio.com/products/Mullard-CV4024-%7B47%7D-12AT7.html

http://www.upscaleaudio.com/products/Mullard-CV4004-%7B47%7D-12AX7-British-New-Old-Stock.html

I have also have just tried the Psvane tubes from Grant Fidelity and really like these too.

http://psvanetube.com/wordpress/?page_id=148

Considerable improvement with the right tubes. I also bought Mullards from Kevin at Upscale. At that time I had a Prologue Three it was night and day difference. Good Luck.

I can't comment on 12AT7's because I never had a piece of gear that used them.

I have in my 12AX7 collection over 50 pairs of tubes from all the European and American companies. Famous Mullards, Amperex Bugle Boys, Telefunkens, Mazdas, etc.

If your piece can use 5751's I have found no tube that offers the sound of music better then these two: 1) Sylvania Gold Brand 5751's either gold or silver pins. 2) Mazda 5751 chrome plates.

They are not inexpensive, but not horrible expensive, and are so much better then even the highest regarded standard 12AX7's regardless the maker or time era. The Mazda's are very hard to get,but you should be able to score the Sylvania's. Remember not just Sylvania, but labed Sylvania Gold Brand 5751's.

agree with above

the 4004 have a big, golden sound that is very pleasing.

Of course it is pretty hard to predict what anyone one person would prefer sonically, so at best, we can only make some recommendations on what to try.

I agree that 5751s are worth trying. They have lower gain than 12AX7s, however, so they may not be true drop-in replacements. I don't know if it is true, but, I've read of instances where the difference in gain adversely affected the phono equalization.

If I had to pick one tube as being almost always an improvement over current production tubes (i.e., a universal upgrade), I would pick an Amperex Bugle Boy 12AX7. These are expensive, but, they deliver a rich, full-bodied sound without being murky or sluggish sounding.

I have tried a pretty wide range of 12AX7s and 5751s in my phonostage. For my particular taste, and given the other components in my system, my personal preference is for the Telefunken ECC803S. But, I can see how this tube would be too lean and aggressive sounding for some systems. This tube is on the opposite end of the spectrum from something like the old Mullards.

My Vote is 12at7 Phillips Miniwatt ( Herleen version ) and Sylvania 5751 3 Mica Black plates..Good match using these together also..Been using them for years in my Thor Linestage.........

The best 12AX7 is not a 12AX7. The best 12AX7 is a 7058. There is just one rub. The 7058 is an extremely ruggedized 12AX7 substitute that was designed for automotive use. The rub is that it only operates with center tapped heaters and will not operate with series connected heaters. If it works in your phono stage, it will be an excellent contender for best 12AX7. As a bonus, it's cheap. 6681 is a very nice instrumentation grade 12AX7 that is a direct sub, no caveats.

The best 12AT7 is a 6201. There are many great makes of this instrumentation grade 12AT7 to choose from. Mullard, Tele. I like the Sylvania Gold tubes. On the plus side, they are a direct sub for 12AT7 on the negative side of the ledger, they are spendy.

Good luck with the hunt.

Thanks everyone so far. I'm currently running the tubes that came with the unit. Svetlana 12AX7's and Electro Harmonics 12AT7's. How do these tubes compare with some of those favorites mentioned? What kind of sonic impact can I expect from rolling in some of these other tubes. While I've got the experts assembled, is there any performance differences between the various Mullard 5AR4 rectifier tubes? For example, some are listed as f31 others f32 etc denoting (I believe) manufacture date. Which of these are considered the best that Mullard made?

The very, "best" 12AT7 family tubes, are supposed to be Tele ECC801S's(http://www.jacmusic.com/nos/ECC81.htm), and for the 12AX7 family; the ECC803S's(http://tubedepot.com/pa-ecc803s-tele.html). Good luck, trying to find those, for less than your First Born male child. Whether the extremely clean sound of these would appeal to you..... well- that's what tube rolling is all about. BTW: Whatever you order; be certain they are graded for phono stage use(Upscale does a good job at this. Check their grading system). Any noise, in the phono circuit, will be VERY obvious at your speakers. As to the 5AR4/GZ34 Mullards; as long as you find one from the Blackburn Plant, you'll be happy(http://www.ebay.com/sch/i.html?_nkw=mullard+blackburn+gz34&_sacat=0&_dmd=2&_odkw=mullard+5ar4&_osacat=0&_trksid=p3286.c0.m270.l1313).

Dodgealum, I'd like to correct a few little errors I see being made already ;--))

First concerning 5751's: the 5751's (and 6201's) were originally made for all branches of the military (a "ruggedized" version of the 12AX7 and 12AT7 respectively). And while it's true they have gain curves that are 70% of a 12AX7/12AT7, that difference occurs mostly at THE TOP OF THE CURVE! Most of the curve for the two kinds of tube (12AX7 v. 5751) is identical over the tubes' operational ranges. Think about it; would the military purchase substitute parts that provide only 70% the performance of those they replace? I don't think so.

As for which ones are best, the best place to start reading is (the now ten year old) Joe's Tube Lore at Audio Asylum: http://www.audioasylum.com/scripts/d.pl?audio/faq/joes-tubes.html
I agree with most of Joe's conclusions -- certainly tried many of them, but my own preferences are either the Sylvania or the RCA 3-mica blackplates (NOT the grayplates). The consumer version of the Sylvanias were marked "Gold Brand", but most of them carry only military numbers BECAUSE they were for the military!! The Gold PIN Sylvania 3-mica 5751 is NOT a military tube; and, it only came with gray plates! Not a bad tube, but the black plates sound better to me, and there's no need to pay for those fancy gold pins (which you can't see after the tube is installed anyway ;--) AND they ALL have copper plate-support rods (which you CAN see ;--) All the Sylvania and RCA 5751 TMBP (triple mica black plates) have steel pins, and both brands sound about the same to me, (very smooth and grain free compared to ANY 12AX7.) The RCA's are about 25--30% cheaper than the Sylvanias in matched pairs (thanks Joe!) The one 'regular' type 12AX7 I really love (it kick's ass with rock music -- and it's still cheap) is the RCA 17mm long blackplate! Wow!

The 12AT7 v. 6201 story is about the same as for the 5751, with a few variations:
Sylvania 6201 blackplates come in both 2-mica and 3-mica versions. With and without gold pins. Take your pick, they're all good.
RCA 6201 blackplates come in 2 and 3 mica versions as well, IIRC.
Siemens 6201's have excellent bass if for any reason you need a little extra at that end of the frequency spectrum (like bass-shy monitor speakers.)
Valvo blue label with gold pins are considered the best 6201's by some, including me, but not anymore. Read on . . . . .

In my ever so humble opinion ;~)) The absolute, hands down, best 12AT7 (nothing even comes close, no 6201, no anything!) is the GEC A2900; or the military version, the CV6091. They come in a few variations, and I've heard them all. Maybe there are differences, but they are so far ahead of whatever is in second place, it really doesn't matter! They come with 2 or 3 micas, blackplates only, regular or 17mm longplates, pan, square, or halo getters. Pre and post 1970's. The only common/consistent thing about them is their performance and their price: both off the charts; with the former being the reason for the latter ;--) I started collecting them when they were about $85/matched pair on eBay. Now they are hard to find (with good measurements) for much less than $250/pair, whether new (1980's) or vintage (pre 1960's.) I wish I could tell you how I originally stumbled upon them, but that story is lost . . . . . One of the most worthwhile spots for these tubes in a piece of audio equipment, is as drivers for high-performance power tubes (KT88's 6550's) I've used them in my McIntosh 275 to drive NOS Gold Lions, EAT's, and (currently) Shuguang Black Treasure series KT88Z's The effect is a bit like adding octane-booster to your gas ;--) Although you won't realize quite as much improvement with lower transconductance KT88's (like the Russian Gold Lion reissues, Pentas, Electro Harmonix, Svetlanas, etc.) These GEC tubes have so much gain, while being absolutely smooth and quiet, that I'm looking for a tube phonoamp that uses them just to have my mind blown! ;--)

I'm not a fan of Upscale Audio's NOS vintage tube products, primarily because their prices always seem to exceed their tubes' performance, (which is usually average or just below.) Their NOS tubes are generally reliable because they do test them thoroughly; but for best price and highest test measurements, I can do MUCH better on eBay. Plus, UA uses some fictional measurement system which makes it impossible to compare their tubes with tubes measured conventionally -- until you get them home and put them on your own tester . . . . Uh-oh!
.

Has anyone tried the Sophia Electric 12AX7's? I bought a pair of their 6SN7's for my Modwright LS100 and they are beautifully made and excellent sounding tubes, far surpassing the stock tubes that came with the unit. I'm considering trying their 12AX7's for my Herron but was wondering if anyone else had tried these--I see they are not mentioned so far. Also, one kind A'goner sent me a pair of tubes to try in my Herron. I haven't tried them out yet as I've been breaking in the Modwright. Meanwhile, we switched over to a new computer and I've lost his email. If you are out there please contact me and thanks again!

Anybody has any experience with valvo 6201 blue label triple mica pinched waist ( 12at7) ?

yes ,they are the best of 12at7, very sweet sounding tubes , accurate bass , details , open ,transparency and ultra rare very hard to find .vttc

Be careful with recommendations of one variant or another being the
"absolute best". For instance: "The best 12AX7 is a 5751,
the best 12AT7 is "variant XYZ", etc."

While it is true that a PARTICULAR BRAND/VINTAGE variant can be
better IN YOUR EQUIPMENT, there are a lot of poorly made and
mediocre sounding variants of many types of tubes. For example, many
tout the superiority of the 5751 in my EAR phone pre. While it is true that
the Sylvania and GE 5751's sound very good in it, IMO they don't compare
to the Telefunken 12AX7. And I have some 5751's by other manufacturers
that sound much worse than some very ordinary 12AX7's.

I have amperex bugle boy, telefunken ribbed plate , mullard long plate, cv4004, and telefunken ecc803s is the best for my equipment. No contest

Sylvania black plate triple mica is hands down one of the best 12at7
Ever made.as far as mid- low Bass possibly The Best.

There is a lot of varients,for both tube types mentioned for sure
The black plate RCA Command series is a standard of excellence against any company, also Sylvania Gold Series these are some of the best the US made, also a gt tube with a WA or JAN were military issue and allways doubled screened for noise. And there is no such thing as best for General Electric also makes the 5 star series also very good ,more of a neutral
Tube that is very well balanced the RCA is usually the warmest,with the Sylvania a bit cooler, the Black plates are the oldest and also a bit warmer then the 60s grey plate versions .then you have Phillips ,which owned
Amperex,and Mullard the SQ, And PQ are there better grade.there is
Many who like Siemens of Germany,if buying the Siemens ,Halsky is their older better tube earlier 60s,Telefunken with the Diamond in the glass
These have European numbers all very good every brand has it's own tonal balance . The tube that sounds best in your system is the best tube.
European tubes are much more $$ then US tubes.Amperex was made in NY for example their white labels are premium and have great detail and a little body - PQ, buy also made in Holland,and other factories.This is just a sample there are many good tubes out there
The rarer the tube the more money,also look for very close matched pairs
And have checked for low noise .enjoy your Valves as the Brits would say.

without getting into anything too exotic,ive had good results with the new tung sols and new mullards,,,however there is some great tubes now coming from canada