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. 

Yeah, it can just be different, not better or worse. That's what Brent from Audio Tubes told me when I asked him about possible comparison in my amp between RCA black plates and Mullards, don't remember the exact model. And I decided not to get the Mullards since I liked the sound I had and didn't want it to be any warmer than it was. But someone else might've wanted exactly that, it would've been excellent sound too.

But for 12AX7 in the preamp my Mullards go nowhere.

All,

Trust is a rare commodity in this hobby.  Being new to tube gear, I really appreciate all of the experiences, insight and recommendations.

Also, FYI - I contacted the folks at premiumvaccumtubes.com.  Their business model is 'don't call us and we won't call you'.  That's correct.  They will only communicate via email or chatbox. 

Hard to say if they are ethical, but I know I will shop elsewhere - the other vendors are happy to discuss their products, and that rapport creates trust (and, thus sales).

@audition__audio   @lowtubes. Thank you both.  It was my understanding too that all three were an arm of Amperex/Philips. The reason I asked who made what for who is I remember reading (can’t remember where) that Mazda did not manufacturer tubes…they were a rebrander only.  In any case they all do sound different.  I have all three varients of 12au7’s and have enjoyed them all over the years depending on the component they’re placed in, system matching, my mood, etc.

@audiojan 

You have a nice system. I use telefunkens and hope they will last a really long time.

When I read your first comment it seems like you're being kind of cheap. Why are you limiting your purse string in this area.??

I don't like trying out different types of tubes I just settled for something that I knew would be exceptional purchased from Jesse. 

@lowtubes there comes a time where tube life may actually exceed one’s own. Maybe a gruesome thought to some, but may as well face reality, lol. With the number of tubes I’ve collected over the years, I’ve decided to try listening to them rather than just collecting ‘em.  Kinda like money…can’t take it with ya.😵‍💫

I don’t recommend people buying a lot of tubes as I e done but I think it’s fine to pick up 2 or 3 different pairs of well respected vintage tubes and hear which they prefer. But if someone is already happy with the tubes they’re using, then I don’t see a need to try something else.  I’ve always did the tube rolling thing because I was curious about the differences. But nowadays, if I get a new component in my home and if it sounds good with the existing tubes, I usually leave it alone. About a yr ago, I purchased a very large single ended tube amplifier that uses GE 805 tube driven my a 300b and some small GE 5751 tubes with a Amperex 12ax7.  All the tubes in the amplifier are vintage and to me, the amp sounded fine. So I left all the existing tubes in the amp and went on to purchasing many of the exact tubes as backups. I don’t like having such a big collection of tubes and that is gonna be my children’s problem when I die. I feel having tubes in stock is similar to having cables in stock. All these things are tweaks to perfect the ultimate sound. I have a decent collection of cables as well, Interconnects, power cables and speaker cables. I own about 5 tube testers and have about 15 tube amplifiers.  Not suggesting anyone go to this level as I know I’ve went too far.  

@lowtubes

Man you’re speaking like a kindred soul here - I feel almost exactly the same way, and yeah, I also went way too far. On the plus side, my tube needs for life are easily filled. On the downside, it’s far too hard to liquidate these collections without a lot of give-aways and/or accepting pennies on the dollar. I'm just not into recouping funds 100 bucks at a time, for the effort involved here. So eventually, someone inherits the problem.

These days I spend less time tube rolling, because most vintage small tubes sound really good anyways, and your hearing just adapts to their nuances over time. If I want to change sonic flavors in a much more meaningful way, it’s easier to swap a cartridge or SUT (or components, or speakers).

Versus signal tubes, power tubes actually yield a more meaningful delta to shaping the sound IMO, but they’re mostly new (not vintage) and it’s pretty quick to hone in on which is the "right" choice for an amp. With small tubes you can easily get into a back-and-forth never ending hell trying to figure out which you actually like better.

It’s nice to know we’re not too crazy despite what our better half will tell us.  

No, we are not, but still crazy enough.

Most of my audio friends have collected way more stuff than what they need. I think this is something pandemic to this hobby and it happens over time the longer someone stays in it. My close friend has more than 15 of the best and sought after tube testers. Tons of other stuff like over 30 Guitars cause he’s a musician also. Reason why I got so many 12au7’s was in the beginning of me entering this hobby, my main pre for almost 10 yrs used only that type tube in the linestage. And back then, (over 30 yrs ago) we didn’t have so many various cables to tweak the sound as we have today. So tube rolling was a big thing then. Today there are additional options like trying different cables that do practically the same thing more or less. I use both options when I’m able. 

Tube rolling seems to be the correct way to begin fine tuning the sound. Cables and power cords should come next, I would think.

I know that a lot of the older 12au7’s can sound very different. Some I’ve found to be very bright, other thin sounding. Others too soft, others lacking in the highs, other with too much highs or lacking in deep bass etc.  So I’ve heard many different sounds from vintage 12au7’s but what I like about them above current production is that I feel vintage tubes are more transparent and flesh out and breathe the music through better. I will say I’ve heard some vintage tubes that have been veiled and aren’t so transparent and not as good as I expected and don’t like them but I will honestly say I haven’t ever heard a new or current production tube sound better, in terms of transparency and fleshing out the musicality better than some of the well respected and reputable vintage 12au7’s.  I think the only way we will see some current production tubes outperforming these classic vintage tubes will be if a company takes on the process of building high quality tubes as they did years ago. And as we see that happening today, those tubes from these companies usually cost $$$.  My friend paid a couple of thousand of dollars for a pair of Elrog 300b tubes. 

Elrog 300b = $3,500 pair

I  spent $450 for very close tolerance within 2% medical grade Telefunken with the red tips worth every penny and last for years.

if you want a very good modern tube -12au7 

at APIs audio  Rays select tubes  hand picked closely matched made to a very high standard and a full 1 year warranty for-under $200 . I have the Rays big bulb 6SN7 

complementing the Tele 12AU7 in my LSA preamp is sounds very good .

Rays select 12AU7  

https://apos.audio/collections/top-sellers/products/apos-ray-tube-12au7

Ray tubes ? Made in China or where ?

I like Telefunken very much. Always found them to be very open and musical. They last for yrs. In fact all of my tubes, doesn’t matter what brand last and have never worn out. The only tube I remember having problems was the Sylvania triple mica black plate 5751.  It’s maybe considered one of the top 5751’s but for me always had a high failure rate.  Even all my power tubes have lasted these 30yrs because I have several amps and I use all my amps so my tubes have never failed except for going faulty.  I like the 6SN7 tube and I have a lot of the true Sylvania Chrome  Domes made in 1952-53 which is a really nice tube.   Also have the 1940’s Holy Grail 6SN7 Tung Sol round plate smoke glass.    For me, I liked many many of the different vintage 12au7’s including the Mullards but my favorites were the Amperex.    I felt Amperex had everything all in one tube. There are many different versions of Amperex 12au7’s, I liked Old World Logo and the 7316.

I'm also going to test different 6sn7's. I already have a pair of Sylvania 6SN7GTB Chrome Tops and I'm getting a pair of Melz 1578's (which likely will take quite some time to arrive since they're coming from Ukraine). They're kind of on two different sides of the spectrum where the SYL is a bit darker and with better bass and scary good midrange than the 1578 which is supposedly a bit brighter, super detailed and widest/deepest sound stage, but lighter in the bass.

I'll keep posting my findings as I get some time to do a proper run through them all (and all combinations...)

I never thought the Sylvania GTB was anything special. Very warm midrange and extended top. I liked the Raytheon 6SN7 WGT brown base which is a really nice sounding tube. For 12au7’s, I liked Raytheon’s, RCA black plates, Valvos, Brimars, didn’t like many Siemens because in my circuits they sounding bright. 

Yeah, GTA / GTB variants aren’t as good sounding as most of the older 6SN7GT tubes. You would need a GTA / GTB for 2 reasons:

1. Your tube slot (usually preamp or phono stage) is particularly sensitive to noise and microphonics. GTA and GTB tubes tend to be a LOT less microphonic than older GTs. Especially quiet are Sylvania chrome tops with the angled plates.
2. Your amp slot specifically calls for a GTA / GTB because it’s running a higher plate voltage and/or dissipation than spec’d for GT or 5692 (this one is even lower spec’d than GT so watch out). Sometimes driver slots in amps do this - like VACs, which specifically label these slots "GTB". You can often "get away" with running a GT or 5692 past its spec’d limits, but they might not last as long. Adding to the confusion: New Sensor makes an Electro Harmonix 6SN7 without "GTB" labeling, and a Tung-Sol variant that is labeled "GTB" - but they both have the SAME datasheet specs. Fortunately, it’s the higher GTB spec, so these are both safe for use in strictly GTA/GTB slots.

If you find you really need GTA / GTB (these are the same for audio applications), you might look for older 1950’s Sylvanias with deeper chrome tops and (sometimes) tall bottles. Sylvania really started cutting corners on production costs & quality in the 1960s. Their tubes also lost their beautiful midrange, sadly. Then they became Philips ECG and at that point, they practically sound like solid state devices.

@audiojan also try some RCA 5814’s with your Sylvania’s. They are warmish but seem to go nicely with the Sylvania’s I’ve tried in my preamp.

@inna rumor is PSvane makes many of the Ray’s tubes.

@inna rumor is PSvane makes many of the Ray’s tubes.

Right, but these days who else could it possibly be? We could pretty much guess that every time, and be right :) 

• New Sensor is doing just fine with its own fleet of sub-brands, and probably doesn’t want to encourange new brands (beyond a simple re-screen of labels) to compete with those.
• JJ / Czech can do it, but you can spot their trademark spherical glass domes from a mile away, and many of us avoid them out of habit & experience.
• Western Electric is too busy trying to establish itself as a high end option, trying to expand its tube offerings (very difficult w/ necessary tooling), and pushing its amp line
• Shuguang is gone? TJ Full music has always been small scale.

marco1, I see. I just don't want any Asian tubes in my amp, or current production Russian ones, for that matter. I am a NOS or good used Old Stock kind of guy. I just have to use earlier production Svetlana/SED EL34 "Winged" because Western vintage tubes are too expensive, when you can find a matched quad.

mulveling, it's interesting what you previously said about power tubes influencing sound more than signal tubes. I remember conversation with Kevin of VAC and he said exactly the opposite. I myself have no opinion, I didn't compare power tubes, but doing a little of tube rolling with 12AX7 in the preamp and 12AU7 in driver slot reveals big differences.

I remember conversation with Kevin of VAC and he said exactly the opposite.

I generally agree with what Kevin says, but we're all individuals and different in key ways. Anyways, he's almost certainly referring to rolling different makes of the same type. Meanwhile, I'm much more willing (than most) to play fast-and loose with rolling different types into power slots, as long as it's guaranteed safe. E.g. KT88 versus KT90 and KT120 or KT150. Depending on amp, you can even mix more different types in there, like EL34, 6L6GC / 7581A, etc. 

This will certainly make many cringe (maybe Kevin too), because the fact is an amp can only be "optimally" designed for the parameters of 1 output type. That's why I called it "playing fast and loose". But here clear as day, I can hear one of my VAC amps (450S) sounding far better with KT120 than the KT88 it was designed for - in THIS room, on THESE speakers. Meanwhile, another VAC amp (Master 300) sounds far better with the GL KT88 it was designed for, than those same KT120. The sonic difference from these KT88 versus KT120 rolls is far greater than any small-tube rolls. KT150 does the same again, but there I've always found the results too bass-heavy. 

mulveling,

I see, now I understand what you were saying. So you were both right.

Mulveling, good points on the 6SN7’s.

 Audiojan, reason why I think it’s important for one to hear the tube in ones own system is because what sounds good in someone else system may not sound best in yours and you might have a different preference. Example, many people like the 1940’s Metal base Sylvania 6SN7GT or 6SN7W. I really don’t, I prefer the Sylvania 1945 6SN7W short bottle because I find it sweeter and nicer than the more expensive and sought after metal base (taller bottle) which I find a little too analytical for my taste. The 1945 Sylvania 6SN7W short bottle and the 1951-53 Sylvania 6SN7GT Chrome Domes are probably my favorites from those type tubes. Mulveling, you mentioned Shuguang and JJ Czech in your post. Because I use so many EL34’s, I’m using 8 Shuguang in my CJ Premier Four and in my CJ Premier 1b, using 12 JJ from Slovakia Czech. My VTL all have 16 Russian EL34’s.

Inna, I never thought the Svetlana/SED EL34 "Winged" were anything special. And even though people claim they are a close copy of Mullards, they’re not. Not even close. I’ve found a few EL34’s that nicely outperform the Svetlana tube. One of my personal favorite EL34’s are the 1970 Tesla brown base. Very revealing and beautiful sounding tube. I like it in some ways better than my Mullards.  The Svetlana winged C doesn’t compete with these caliber of EL34’s even though people have falsely claimed so. I mention in a previous post, I would only use inferior tubes in my equipment because it might be too expensive to use premium tubes. On my amps that ONLY require 4 EL34’s, I have on most of the 1970 Teslas, 1960 Mullards or 1960 Amperex XF2. 

lowtubes, though I did not compare EL34 tubes yet, I too can't say that I hear anything special from SED tubes, not that I expected it. They seem to be alright, nothing more. That's why I of course want to find a reasonably priced matched quad of XF1 or XF2 Mullards, even used from a reputable source. Tesla, yes, I heard about them, saw them on ebay and nowhere else.

Mullard EL34’s are great and there is opinions about the differences in sound between the single and dual getters. I think I have both but never compared to hear which is better. I did evaluate between single getter 1960’s Mullard and 1970’s brown base Tesla dual getters. The amp I used to compare these tubes was a Conrad Johnson MV55, with 1945 Sylvania 6SN7W short bottle driver tubes and 1950’s Mullard MCI long plate 12ax7’s driver tubes. The Mullard is just a great all around tube. Very well balanced with Great detail, smoothness and musicality. I found the Tesla, in my amplifier tested, to be more euphoric and engaging. The Tesla had something special that fleshed out the information above the Mullards. Strange thing, even though I feel I was getting a more fleshed out midrange and more immediacy from the Tesla’s, they also had this sense of warmth to them. When I heard the Mullards, no warmth, just musical and straight up good tube. When I play the Teslas, warmth and euphoria and midrange clarity returns. 

Mullard MCI 12ax7 input tubes. 

Do you ever somehow try to musically match 12AU7 driver and power output tubes in advance or it is just a matter of experimentation? I mean, if I am lucky at some point and get a set of EL34 Mullards should I also consider replacing 12AU7 RCA blackplates driver tubes with Mullards ?

No I do not ever try to match brands of tubes together nor have I ever thought about that neither do I see any benefit to it. Almost all of my equipment is operating with all different brands of tubes. Even though I had Mullard MCI 12ax7’s as input tubes, my favorite 12ax7 is the Amperex long plate double DD getter. But at the time of evaluating the EL34’s, I had the Mullards in the input. The Mullard MCI btw are some of the best 12ax7’s ever made.  In the beginning, Depending on the type of tube equipment I’d own in the past, I usually was very curious at how much improvement in sound I could get by picking up premium tubes that were favorites by many audiophiles that were in the hobby before me. Slowly I began purchasing tubes and listening to them in my amplifiers to hear what they sounded like and to satisfy my curiosity. Nowadays when I’m in need of a specific or special sound I’m hoping to achieve, I have some of my favorite tubes to put in place and see if it helps. Ive been in this hobby for 30 plus years and I already know by listening to a system if it’s good or if it’s lacking. I only swap tubes today if I hear a problem. If it sounds good, I change nothing. My ears tell me when something is transparent, revealing, airy, engaging, natural, and all the beautiful things we want to hear from our systems. If I purchase a new piece of equipment that has Chinese tubes, I very much might keep those tubes in as long as it sounds transparent and good. When I purchased my Conrad Johnson Premier Four, it arrived with 8 Shuguang Chinese EL34’s. First thing I wanted to do was get them out and put something better. But after playing the amp for the first week, I found no issue with the Chinese tubes. To my ears, they sounded great and were doing the trick. So instead of putting in 8 Teslas, I searched for more Shuguang tubes and purchased 16 as backups because in the end, it just sounded fine. I did change out the input and driver tubes on the amp to something better from my vintage stash. I feel setting up a system is a mix of a lot of different stuff. I don’t recommend using the same brand of tubes the same way I wouldn’t recommend using the same brand of cables throughout a system. Building a really nice sounding system is something that is done one step at a time and to get it to be really, really good, it usually takes time tweaking and making little but worthwhile adjustments. It can take yrs till it all finally comes together and the funny thing about this hobby is that when that happens, usually audiophiles still aren’t happy.  I do t think many audiophiles will ever be content or happy with their systems.