12au7 tube?

@twoleftears 

I forgot all about them.  They came on like gang busters advertising everywhere and then just stopped. I’ll be listening to hear what answers you get.

Oh and thanks for jogging my memory.😊

Hello AudioJan, came across your topic from the list that is sent to me weekly by audiogon. Saw an interest in your question about 12au7.  I’ve rolled that tube for years and have a huge inventory of the finest and best 12au7’s ever made. I didn’t read all the responses to your question but I saw many responses in which I feel were correct. I’ve found for myself that many 12au7’s can sound more transparent and revealing than other brands. Some are more musical and some more detailed. I’ve also discovered that the “holy grail” of a tube may not necessarily be the tube that sounds best in your setup even though it might be the clearest and most revealing.  When I’m looking to tweak and make adjustments to perfect my sound, I’ll try the many various 12au7’s I have in stock, (somewhere around 60-70 different brands NOS).  I happen to be bias in that I prefer older 12au7’s tubes from the 1950-1980’s. I may go through 1-10 different brands till I find the tube that sounds right even though I’m dealing with some of the very best ever made. Point is, you definitely want to begin evaluating with a great tube to hear if it’s gonna sound good but to find the perfect one for your system, you’ll need to try as many as you can. Unfortunately there’s no easy way around this. Me and my buddies have been rolling tubes for years and no-one can really tell you what will be the right tube for you in a particular component because that component is part of a complete system that all the other parts of that system  will all be contributing it’s own sound. There are forums online that specifically talk about tubes and tube types. One that I’ve used many years ago is “Tubes Asylum”.  You can put the type tube you want information on and can read many online responses to that type tube. 

@lowtubes with your expertise in 12au7 tubes, I wonder if you could help clarify something touched on here and something I’m still a little unsure of.  Regarding vintage Amperex, Mazda and Radiotechnique, generally who made what for who? I guess I could ask some of online sellers of vintage tubes but since you’re here and they’re not a clarification could also be helpful to some of the other participants of this thread.

50”s VALVO.

The OS (used) Mullards I got from Andy Vintage Tube Services are fantastic, and not woolly. If you buy slightly used from Andy you can get great vintage tubes for much less than your budget. Recently I bought a quad of Rays tubes, the EL 34. They are the best new tubes I’ve heard in a long time. Their 12 AU7 might be worth trying too

I've had really good luck with the new-production Apos Ray 12AU7s. They come with a warranty and sound very good compared to the leading NOS 12AU7s I have in my stash...

There are so many variations in NOS Mullard tubes (different factories, different styles, a whole range of dates of production), that it's impossible to generalize about them.  I wasn't impressed with the pair that I got, but that doesn't mean that some other pair might sound fabulous.

That's one positive vote for the Apos Ray.  I'm feeling tempted.

You Can't beat Andy @ Vintage tube services.

marco,

The 3 types you mention above are all Philips Europe companies. Made in Holland, Belgium and France respectively. Each has a unique acid etched code which begins the second set of each code. For Philips/Amperex is was a delta or triangle on its side, Mazda a L and LA Radiotechnique a plus sign directly over a slash or minus sign. All have many internal similarities and all have the 4 seams coming out from the nipple on the tube tops. There is much online about these codes and is the only true way to identify a Philips Europe tube and I have never known these codes to be faked. Many of the Holland made tubes will be branded Philips as well as Amperex.

I think, RCA black plates from 50s give excellent balance, at least in my amp. 

Hello Marco1, I haven’t listened to my 12au7’s in a long time and I really didn’t get very interested in where they were made and for what purpose. But off the top of my head, some things I do remember, for instance the very popular and extremely good Amperex 7316 (12au7) was a later production tube made for computer purposes. I believe Mazda was made in France.  Somewhere around 30 yrs ago, I Own a Conrad Johnson preamp for 10yrs that used (2) 12au7’s in its linestage and that was when I rolled and collected many brands and pairs of the 12au7’s. I still have some components in my collection that use the 12au7 but since moved onto other preamps that use other type tubes. All of the well respected vintage brands are worth giving a listen like Mullard, Telefunken, Valvo, Mazda, RCA black plates, Philips, Amperex, and so on.  I have a big inventory of other vintage tubes as well EL34’s, 6SN7’s, 12AX7’s, 5751’s as well many other tubes. In my home, I have many tube amplifiers in my listening area. I prefer tube components and in the past did a lot of tube rolling to get the best sound. Nowadays,  I still use all vintage tubes because I personally feel they sound better. Im not a fan of many current production tubes.  The only areas where I am not using vintage production is the power tubes on 3 power amplifiers because the 3 amplifiers take so many EL34’s and I don’t want to burn up my good Mullards or Amperex, Teslas etc. My VTL mono amps use 16- EL34’s, Conrad Johnson Premier 1b, 12- EL34’s, Conrad Johnson Premier Four 8- EL34’s. I use my premium EL34’s in my smaller tube amps that only require 4 power tubes.  The most important point I would like to stress, no one tube can be recommended to someone to be the perfect tube for someone unless it is heard in one’s system. I’ve forgotten so much about all the tubes I have in storage. But one thing I remember, you need to put the tube in the circuit and give it a listen to hear if its what you’re looking for.  I recently picked up a Conrad Johnson Premier 3 and once again, pulled out my stash of tubes and started popping them in and out till I got the sound I was looking for in the linestage along with the phonostage.