Seeking a Warm 12AX7 Tube for Preamp

@spacecadet65 I bought a bunch of 12AX7, 7025, 5751 and 12AT7 NOS and a couple new production variants to replace a stock JJ 12AX7 that I also found “bright and strident” in a Willsenton R800i 845. The R800i uses one 12AX7 as the V1 signal tube in the preamp section so it has a noticeable impact on tone not withstanding a GFB design. 

The clear winners for “warmth,” which I would describe as enhanced bass response and rolled off treble are the RCA and Brimar black plates. The RCA is the much better of the two, the Brimar is smooth and warm to the point of sounding a bit mushy with lack of detail. The RCAs are warm, smooth and retain detail. A real stand out in my rig is the Raytheon black plate, it is warm yet linear with no high roll off, strong bass, clear airy treble and neutral yet present midrange and superb soundstage depth. Can you tell I really like it!? 

Of the remaining lot, in order of neutral, transparent to detail and airy I’d rank as follows:

GE

Mullard

Telefunken

Gold Lion gold pin from Russia

Sylvania 5751 black plate

RFT

Amperex Bugle Boy

My three favorites are the Raytheon black plate, Telefunken smooth plate, probably the most balanced linear and neutral of the bunch without losing any details, and the Amperex BB. The Amperex is in a class of its own for airy details and a much higher soundstage. The Raytheon has depth and detail with punch, the BB has more detail in the higher frequencies and the soundstage appears two or three feet higher. It’s a great jazz or modern well recorded Indie track tube. 
 

The biggest disappointment is the Mullard. Everyone raves about them online, but in my system, it is just average. Balanced, yes, linear, yes, but nothing special. 
 

It’s possible some of the strident edge is coming from too much gain. You might consider rolling in a 5751 or even a 12AT7 depending on speaker sensitivity. Just a thought.

Cheers,

trivema,

I am pretty much in agreement on your assessment of 12AX7 tubes.  I currently run extremely expensive Telefunken ECC803S (the real deal) tubes in my phono stage.  It is a very dynamic and vivid tube, but, it is not for someone looking for a lot of warmth.  I like other Telefunken variants too.  I am also a big fan of the Amperex Bugle Boys; to me, they are warmer sounding than Telefunkens, but, they remain clear and reasonably dynamic.  I too don't particularly like Mullards.  In addition to being a bit "blah" sounding, in some applications they sound a bit "strange" (sort of phasey sounding).  

I don't really do tube rolling myself, but, I heard a few types when first choosing tubes for my phono stage and in other people's system.  I even tried some 5751s which sounded quite good, although I actually need as much gain as I can get so 12AX7s are a better match.  A friend brought around a big selection of the better tubes he had for me to try.  I liked the Telefunken smooth plates, which is why I went all in on getting the ECC803S when I could do it.

Buy a used Mullard that test as new, you can pick up one for under $100. RCA’s are fun and sound good, kind of in the middle between Mullard and Telefunkens. RCA’s are more of a guitar tube and sounds like it but still a nice tube. Telefunkens are very detailed, refined, either you like them or you don’t. The Gold Lion gold pin sound like they tried to copy the Telefunkens character. If you need a place to buy a used Tele pm me, 

Buy a used Mullard that test as new, you can pick up one for under $100. RCA’s are fun and sound good, kind of in the middle between Mullard and Telefunkens. RCA’s are more of a guitar tube and sounds like it but still a nice tube. Telefunkens are very detailed, refined, either you like them or you don’t. The Gold Lion gold pin sound like they tried to copy the Telefunkens character. If you need a place to buy a used Tele pm me,

I agree with all this, pretty much :)
Used-tests-strong tubes, from smaller tube sellers with good feedback, is THE way to get good value for your money. If you go to big tube dealers, they’ll charge a huge premium, and their tubes aren’t always better. Some of these 12AX7's still have such large populations (most Teles, RCAs, Mullards), it’s crazy to pay big for ’em. A dud happens here and there, but a small tube like this won’t blow up your amp and speakers without LOTS of help from bad engineering elsewhere.

I’d say that reissue Gold Lions remind me more of Amperex (Holland) than Teles, but not far off either way (especially if you mean smooth plates).

What is wrong with Psvane 12ax7.

I use it in my phono stage instead of Sylvania 5751 than I used for many year. And I don't feel that Psvane is inferiors to this great 12ax7.