Looking for 12ay7/6072 recommendations.

[dadydg]

I'm looking for a recommendation for a 12ay7/6072 for my 5E3 Tweed Deluxe. What are your preferences based on tone and low noise.

I'm also interested in folk's feelings about new productions tubes. Are they any others besides the Electro-Harmonix?

Thanks,
Dan

[stokes]

Most 12AY7's are fairly low noise since they have a lower ampl.factor than the 12AX7's.I would suggest finding NOS.I've only tried the EH current production and didnt like it at all.To me it was muffled, not as bright as any NOS,more like using a 12AT7.I have JAN GE,RCA,GE five star 12AY7's and they are all very nice.Like I said I have never had noise issues with this tube,unless it was a bad tube otherwise.Another tube that sounds great in the 5E3 is the 5751,a little more grind than the AY7 but much tamer than an AX7,again I only have experience with NOS so I cant comment on the current production 5751's,but I suspect they cant compare to NOS,but I am an admitted NOS snob,so even if one sounded okay,I probably wouldnt admit it.

[Rob Mercure]

Somewhere I have the original Sylvania "release" article on the 12AY7 from a late 1940s issue of Radio Electronics Engineering magazine and the science, craft, skill, and art that went into developing the original design was amazing! Extra supports and micas were incorporated to ensure rigidity to limit microphonics and the filament was wound in such a manner so that one section would buck out the magnetic field of the other to limit hum, etc.. So - and I do need to find the article and refresh myself again - with the extent of specific design and construction that went into this "purpose built" audio input tube I truly wonder if anyone is making a "real" 12AY7. With potential sales being a small fraction of the 12AX7 - for example - I suspect that the current issues are just a variant of the 12AX7 design instead of being the original unique valve.

While lotsa great new tubes are being made I suspect that any NOS 12AY7 would be vastly superior to current production.

Rob

[Bruce / Mission Amps]

I include the 6072/12AY7 EH tube in my tweed amp kits because they are easy to find and sound pretty good for what they are.
But I find that when I test them on my 539 Hickok tube tester, they always seem to read higher in mu then NOS ones do.
Not as much mu as a 12AX7... so I know they are not a dead 12AX7.
I don't hear the EH as being muddy or darker though.
**********

Yes, when I build one of my own kits for a customer I always use a real NOS 12AY7.

[soundmasterg]

I happen to like the EH 12AY7. It doesn't necessarily sound like NOS 12AY7's, but it sounds good in it's own right and is a reliable tube.

[bob p]

i seem to remember reading that the 12AY7 was heralded at its introduction for exactly the reasons that Rob mentioned. i also seem to remember reading that the 12AT7 eventually picked up all of the technological improvements that were introduced by the 12AY7, and that's one of the reasons that the 12AT7 has largely supplanted the 12AY7 as the medium-mu triode. can anyone comment on that?

[Rob Mercure]

Hey Bob,

I'd also be very interested in that bit of info if it checks out - but could you possibly be thinking of another tube instead of the 12AT7 that benefited from these improvements? While the AT7 has come down over the years as a guitar amp standard the tube was originally designed for RF- grounded grid - designs and is generally scorned by the HiFi crowd. Not that the improvements might not have wound up in the AT7 but since it's internal structure is quite different from all of those 12A_7 tubes we've come to know and love I'd more likely suspect that the improvements wound up in the 12AV7 or even the 12AZ7 (although this latter one is more "AT" than "not") or some tube whose characteristics are more similar to the 12AY7. But ya never know!

SM: While the EH "12AY7" is probably a great tube your and Bruce's comments lead me to believe that the tube EH is marketing is probably a "something else" Russian design, already in production, that is being relabeled - this would be very consistent with Sovwrek/EH/Reflektor past behaviour. The exquisite detail spent on designing the "original" 12AY7 included the transconductance and amplification factor (as well as most everything else) so the idea that a recreation of the original design would deviate much from the original strikes me as "funny" - after all, the idea is to sell these bottles.

Rob

[soundmasterg]

Rob, you are probably right about the "something else pre-existing Russian tube type" part. It would be nice to know the real truth about them, but it sounds ok and works fine in your typical 12AY7 circuit, and is reliable too, so I doubt there is much incentive for New Sensor to publish any info about them.

[Le Basseur]

The naked truth!

It would be nice to know the real truth about them

Well,here's a few infos that I got a long time ago (somewhere in the early-80's) about the ex-Soviet tube industry policy in general.Read on!

I doubt there is much incentive for New Sensor to publish any info about them.

You're absolutely right...despite of the New Sensor's financial "games" in the early 90's (when they bought 49% of Svetlana) and the consequent aggresive marketing,I doubt that the Russians were willing to share their archives and research files.Consequently,no pertinent documentation from NS.

While the EH "12AY7" is probably a great tube your and Bruce's comments lead me to believe that the tube EH is marketing is probably a "something else" Russian design, already in production, that is being relabeled

...and you're entirely right!
The Soviet tube industrial "policy" was mainly oriented towards shamessly copying every Western design they could lay their hands on.
The problem is that the copying decisions were taken on a rather political,concurential level (the commies didn't have any problem about the natural resources,energy,R&D,tooling and labour force in those days).Consequently,the "cloning" decisions were entirely taken by a bunch of undiscerned,non-professional guys whose goals were something like "we don't know exactly what it's good for but let's have it cloned,just in case".
I could name you a few hundreds of Soviet tubes that appeared this way (they even cloned the very rare WE 6386),though many of them were partially unknown to the masses because of the stupid "military secret" policy.
Though...in a spirit of fairness,one should recognise that not ALL the Russian tubes were cloned after Western originals.Some designs,such as 6Н1П (6N1Pi),6Н6П (6N6Pi-the starting point for the 6N30) and 6C19C (6S19S) are genuine Russian designs.Some other tubes,such as GU50 represents a major improvement over the original (in that case,WWII Telefunken and Valvo LS50...the best ~50 MHz glass output pentode in the 40W class ever.)
(One word about the 6N1Pi:the Western tube world is incorrectly putting it in the ECC88/6DJ8/6922 ballpark.6N1Pi doesn't belong there!The exact Russian equivalent is named 6Н23П (6N23Pi) but looks like this is totally unknown...well,no wonder.
The original Russian version of 12AY7 is called 6Н4П (6N4Pi) and it has EXACTLY the same catalog/measured specs and pinout as the original 12AY7,though I've found them a little noisier than a real 6072,maybe because of a poorer filament construction.I'm not sure when the first clones appeared but the two Russian NOS samples I have in my collection are dated 1964 and 1965 respectively.
AFAIK,the 6N4Pi came a little too late...they were used in some short-issued consumer radio receivers and some obscure industrial and military equipment but nothing further.The arrival of the SS devices simply put on a dead line almost all of the "off-the-mainstream" tubes,6N4Pi included.
The EH/Sovtek/whatever modern versions are somewhat different than the 6N4Pi and somewhat closer sonically to the Western-made 12AY7.
I tested all three types (NOS Russian,NOS Philips CGI and modern EH) in my microphone preamps and there's no doubt:NOS russians are the noisiest and unusable.The sonic character differences between Philips and EH is another issue...I found the later to be a little more opened but unrefined.

The exquisite detail spent on designing the "original" 12AY7 included the transconductance and amplification factor (as well as most everything else) so the idea that a recreation of the original design would deviate much from the original strikes me as "funny" - after all, the idea is to sell these bottles.

Exactly my point.
All New Sensor's phoney claims regarding "the invention of the hot water" don't have any real support.It's just marketing hype.
Bottom line:I appologise if some of you found my post to be boring or hard to read but I felt like I'd have to clarify some foggy aspects by sharing some specific informations I got myself through the years from old military techs I spoke with.
Best regards,

[dai h.]

if you want to see a USSR 6SL7, I took some pics of one I have which is an old metal base tube.

http://www.flickr.com/photos/7878340@N05/page2/