Which 12AX7

[jcmusic]

What are you using in your phono stage or critical area of your system? I have been using Tele's for years and it may be time to try something different. Must be dead quiet and accurate...

[JackD201]

3 pairs of Telefunken 803s' in my EMT and 1 pair of the same along with Tele 801s' in my Valvet Soulphono. Stock tubes that were replaced in both cases were JJ Tesla 803s.

[Bill Hart]

I want that EMT when I grow up!

[Bruce B]

Using Tele's here in the Doshi. No need to change!!

[Bob Olhsson]

Unfortunately NOTHING has ever replaced Teles! I fear a lot of younger people have never heard the "tube sound" we all took for granted.

[MylesBAstor]

All depends on the balance of your system.

Also remember, you are not going to throw just any old tube in your phono section. You want as quiet and free from microphonics tube as possible and ergo suggest you get them from a reputable dealer that tests their tubes like Kevin Deal www.upscaleaudio.com (and has phono quality, Mark www.tubemuseum.org (or tubemuseum on eBay), Andy Baumann www.vintagetubeservices.com (caution he may be a little difficult but is very knowledgeable) or Brent Jessie www.audiotubes..com. Preferably a Amplitex or Maximatcher tube tester. Kevin actually has a pretty nice new selection of 12AX7s too.

Also I'd always buy from a reputable dealer but you just never know if the tubes you are buying are really say a MullardTelefunken, etc. made for them by someone else. You want someone who knows the coding.

Teles are good but every tube has their own sound. I've used them and they can be a little lean sounding but very extended, clean and resolving. Of course, ECC803s are a rare breed and will set you back $1000-1500 each. And who knows if they really are NOS.

Mullards (and their different types such as CV4004) are classic tube sound with fuller, big midrange, little ill defined in the low end and softer up top.

Amperex's might be a middle ground between the two above and I'd look into them.

GEs always sound a little bright and hard to me.

I was actually surprised but the new Svetlana 12AX7s that Nick Doshi now includes with his phonostage are darn good.

[Dr.Ears]

I like the Siemens black plates or the Mazda nickel plates, never could decide between them. It depended on the music being played.

[jcmusic]

Ok guys pretty much what I expected and I agree with you all on the tele's. I did however read something a long time ago that until recently had forgotten about, I read that too much of a good thing can expose the weakness. In other words my phono stage use 4 12AX7's and up to this point I have always run 4 tele's. Now tele's may not really have a weakness but, if they do or have a possible weak area. It could be exposed by having 4 of the exact same tubes in there. I am gonna try a couple different high quality tube brands in the secondary position to see if this pans out. My best and quietest pair will stay in the primary position as always. In fact I ordered another matched pair from Brent this morning!!! WOW!!! I haven't bought tubes in over 5 years, my how the prices have gone up!!!

[Dr.Ears]

I found the Tele's to have a bloated mid-range. The best 12AX7 just might be a 5751, which offers only 70% of the gain.
I prefer the 6 volt octals because I think the 12 volt sub-miniatures have too much gain for the small bottle.

[JackD201]

Ok guys pretty much what I expected and I agree with you all on the tele's. I did however read something a long time ago that until recently had forgotten about, I read that too much of a good thing can expose the weakness. In other words my phono stage use 4 12AX7's and up to this point I have always run 4 tele's. Now tele's may not really have a weakness but, if they do or have a possible weak area. It could be exposed by having 4 of the exact same tubes in there. I am gonna try a couple different high quality tube brands in the secondary position to see if this pans out. My best and quietest pair will stay in the primary position as always. In fact I ordered another matched pair from Brent this morning!!! WOW!!! I haven't bought tubes in over 5 years, my how the prices have gone up!!!

Crazy right? It's almost like land prices here! Glad I bought when I did and have a generous brother too.

[MylesBAstor]

Ok guys pretty much what I expected and I agree with you all on the tele's. I did however read something a long time ago that until recently had forgotten about, I read that too much of a good thing can expose the weakness. In other words my phono stage use 4 12AX7's and up to this point I have always run 4 tele's. Now tele's may not really have a weakness but, if they do or have a possible weak area. It could be exposed by having 4 of the exact same tubes in there. I am gonna try a couple different high quality tube brands in the secondary position to see if this pans out. My best and quietest pair will stay in the primary position as always. In fact I ordered another matched pair from Brent this morning!!! WOW!!! I haven't bought tubes in over 5 years, my how the prices have gone up!!!

That's similar to my old conrad-johnson TEA1bc phono section . CJ's phono section used three 12AX7s and two were in "critical" positions" that required low noise tubes. But the third position wasn't as critical and I used to experiment with different tube types. I think at that time I ended up with an EAT ECC83 in the TEA1bc.

IIRC, you can save money with Brent if you go with say the Dynaco, etc. Tele tubes too (as long as they have a diamond on the bottom). Others may be more in the know but supposedly the red tipped Ulm manufactured Teles were the best.

[Dr.Ears]

You can buy ready made adapters which convert a WE 420A / 5755 to a 12AX7. You can also buy 2 for 1 adapters, which convert a pair of 6SF5-GT to a single 12AX7, the 6SF5-GT has 110% of the gain of a 12AX7. Finally you can buy adapters, which convert a 5687 to a 12AX7. The 5687 was designed by TungSol in 1952 to be a superior audio tube. Audio Note's current DAC's all use the 5687.
With quality 12AX7 getting scarce and loads of counterfeits around the WE 420A maybe a better alternative to the 12AX7.

[siddh]

I have had a number of mini tubes in both the drive position of CAT amp and Jadis pre/phono. Tele's always make the final cut. Always. I am greatly grateful I was compulsive and bought a boatload back in the 90's and early 00's.

[nc42acc]

Can a 5751 or a 12AT7 be used in place of a 12AX7? I know the gain factor is lower but what about in a circuit where you have the extra gain to spare? Just a thought?

[Dr.Ears]

They have 70% of the gain and are worth a shot, especially in phono sections, where you want the least noise possible.

[MylesBAstor]

Can a 5751 or a 12AT7 be used in place of a 12AX7? I know the gain factor is lower but what about in a circuit where you have the extra gain to spare? Just a thought?

The only was to be sure is to check with the manufacturer because the 5751 isn't a drop in replacement for a 12AX7. Those old RCA 5751 windmill getters sold at one time by Gold Aero years ago were the bomb! Sounded wonderful in my cj equipment.

[Dr.Ears]

The 5751 has 70% of the gain of a 12AX7 in many holes the 5751 sounds better because it has less gain.

[Steve Lefkowicz]

i was just chatting with George Counnas from Zesto Audio about this the other day. He had a lot of nice things to say about the JJ 12ax7 803 long plate gold pin tubes. I use standard JJs in my primary power amp, and thought i'd try these next.
https://www.tubesandmore.com/products/T-ECC803-GLD-JJ

[jcmusic]

Can a 5751 or a 12AT7 be used in place of a 12AX7? I know the gain factor is lower but what about in a circuit where you have the extra gain to spare? Just a thought?

I have used both of these tubes in the place of AX7's before just a different gain. However I don't think the AT7 is very musical at all I don't use them anymore at all.

[nc42acc]

Please elaborate what experience tarnished your opinion of the 12AT7?

[MylesBAstor]

i was just chatting with George Counnas from Zesto Audio about this the other day. He had a lot of nice things to say about the JJ 12ax7 803 long plate gold pin tubes. I use standard JJs in my primary power amp, and thought i'd try these next.
https://www.tubesandmore.com/products/T-ECC803-GLD-JJ

He must be having better luck with them than I did.

[Steve Lefkowicz]

He must be having better luck with them than I did.

I'm guessing has has. Looks like he specs various gold pin JJ 12ax7 or 12au7 tubes in most of his gear. Honestly, I've had great results with the JJ 12AX7 tubes in my Antique Sound Labs amp. I've swapped out for others few times, usually when amps in for review have other brands of 12AX7, and haven't heard a reasonably priced set I felt sounded better in that amp.