The Dynaco Tube Audio Forum

Dedicated to the restoration and preservation of all original Dynaco tube audio equipment - Customer support for Dynaco VTA tube amp kits, all Tubes4hifi.com products and all Dynakitparts.com products


    "Super" 12AU7?

    Share

    sKiZo

    Posts : 1285
    Join date : 2013-04-01
    Location : Michigan USA

    "Super" 12AU7?

    Post by sKiZo on Wed Feb 11, 2015 8:49 pm

    OK ... this is a new one on me ...

    Just got an email from PCX advertising a sale on these. It's an RFT ECC813, and it does require an adapter (included) to replace a 12AU7. From what little info I can find, they're electronically identical except for the pinout.



    Huh. Any experience with these?

    BNR_1

    Posts : 78
    Join date : 2013-06-11

    Re: "Super" 12AU7?

    Post by BNR_1 on Wed Feb 11, 2015 10:17 pm

    Do share your impression. Never heard of an ECC813.

    That is a nice socket convertor.

    gener8r

    Posts : 56
    Join date : 2012-04-28

    Re: "Super" 12AU7?

    Post by gener8r on Wed Feb 11, 2015 11:52 pm

    Wow, never heard of these either. Thanks for posting.

    IMHO nothing beats a Mullard long plate 12AU7, except maybe a Brimar 13D5.  As an octal alternative, the 12SX7 is mighty fine.  If this ECC813 is better sounding than any of them you really have something and worth whatever you paid for it.

    Are you familiar with pretty much last tubs ever developed by Telefunken, such as their "super 12AX7" which is the ECC808?  The ECC808 was developed by Telefunken specifically for audio applications and placed in some of the last electronics they ever produced.  Supposedly better than a Telefunken 12AX7 smooth plate.  One day I'll have to unbox the NOS pair I have to find out........

    I wonder if these ECC813s are in the same mode as the ECC808, one of the lasted upgraded tubes ever made?

    gener8r

    Posts : 56
    Join date : 2012-04-28

    Re: "Super" 12AU7?

    Post by gener8r on Wed Feb 11, 2015 11:56 pm

    I also meant to mention the ECC808 has a different pin out than the 12AU7 in that its shielded to ground on what would be pin 9 of the 12au7.  If the ecc813 is similar you may want to take advantage of that shielding.

    tubes4hifi
    Admin

    Posts : 1261
    Join date : 2008-11-30

    Re: "Super" 12AU7?

    Post by tubes4hifi on Thu Feb 12, 2015 12:07 pm

    it's a 6463, I've seen them as low as $4 each, although these are probably premium tubes.
    they have the same gain as a 12AU7, but higher Gm and lower Rp than a 12AU7.
    Also, pins 2 & 3 and pins 7 & 8 (the cathode and grids) are reversed from a 12AU7 pinout.
    They also use double the filament current. Haven't heard one.

    sKiZo

    Posts : 1285
    Join date : 2013-04-01
    Location : Michigan USA

    Re: "Super" 12AU7?

    Post by sKiZo on Thu Feb 12, 2015 1:35 pm

    gener8r wrote:I also meant to mention the ECC808 has a different pin out than the 12AU7 in that its shielded to ground on what would be pin 9 of the 12au7.  If the ecc813 is similar you may want to take advantage of that shielding.

    Hard to verify as I have yet to stumble across a data sheet for these things. Very little info of any kind.

    Aha! Got the data sheet! Not a lot of similarity ...



    Last edited by sKiZo on Thu Feb 12, 2015 7:10 pm; edited 1 time in total

    sKiZo

    Posts : 1285
    Join date : 2013-04-01
    Location : Michigan USA

    Re: "Super" 12AU7?

    Post by sKiZo on Thu Feb 12, 2015 7:08 pm

    Not to start the rectifier debate yet again, but I do believe my GZ37 has ample reserves to drive some of these. If I remember right, lower Rp is normally a result of higher Gm, and coupling that with an equal gain (Mu), any real difference should be in tone. Also as expected.

    As mentioned, the pin out differences aren't an issue using the adapter. The larger elements should also have an impact - depending on the grid structure, the tube COULD be a lot quicker - maybe similar to the 5814, but without the bass bump. I do like the idea of a stronger upper mid with my system ...

    Also opens up some new options using the adapters, including the ECC 86 and 6GM8. Not sure if those would require any other changes to the ST120 - they be plug 'n pray.

    Hmmmmmm ...

    PS ... I just got an email back from PCX, and they will match a triplet for an additional $10. Also got a link to a data sheet ...

    http://www.partsconnexion.com/prod_pdf/nos_73253.pdf

    skriefal

    Posts : 116
    Join date : 2011-09-20
    Location : Utah, USA

    Re: "Super" 12AU7?

    Post by skriefal on Sun Feb 15, 2015 7:08 pm

    Have you tried RFT ECC82s? They're easy enough to find at reasonable prices -- say $30 for a pair or $40 for a quad.

    sKiZo

    Posts : 1285
    Join date : 2013-04-01
    Location : Michigan USA

    Re: "Super" 12AU7?

    Post by sKiZo on Sun Feb 15, 2015 9:02 pm

    I hear they're quite nice and exceptionally quiet, but I've got plenty of 12AU7 variants, including the RCA clear tops usually quoted as similar overall. Was looking for something ... different.

    Those "super" tubes BETTER be super at $130 for a matched triplet ... Shocked

    Still ... I've been a good boy ... haven't bought a driver in months ... well ... weeks anyway. albino

    Thanx for the reminder though ... think I'll swap in the clear tops for a listen. Those were the first set in the amp, and not sure if they sounded as spectacular as I remember, or it was just initial infatuation with the amp ... one way to find out.

    PS ... currently running a Sylvania 12BH7A in center position flanked by a matched set of Westinghouse Star 5963's ... Very strong combo with an extremely tight bass and punch. Sound stage is a bit small compared to some, but still a very pleasant combo, especially with modern jazz ...

    skriefal

    Posts : 116
    Join date : 2011-09-20
    Location : Utah, USA

    Re: "Super" 12AU7?

    Post by skriefal on Sun Feb 15, 2015 9:09 pm

    I have enough old-production 12AU7s to last a few lifetimes, so I wouldn't drop the $130 on the ECC813s. Especially given the uncertainty of whether they'd work (or work well) in the ST-120 or M-125s.

    But if someone else tries them and finds that they're the most wondrous option, well, then.... maybe...! Ha.

    sKiZo

    Posts : 1285
    Join date : 2013-04-01
    Location : Michigan USA

    Re: "Super" 12AU7?

    Post by sKiZo on Sun Feb 15, 2015 9:23 pm

    Ya ... I was hoping to find someone who's experienced them ... or maybe talk someone else into trying them ... I'm sure volunteers are lining up as we speak. ;-}

    The actual price for the tubes themselves isn't all that bad - half the cost is for the adapters. If other variants are available for rolling, that makes the initial outlay more of an investment.

    (Which is the same sort of argument I usually use to talk myself into things.)

    zx

    Posts : 194
    Join date : 2011-08-05

    Re: "Super" 12AU7?

    Post by zx on Mon Feb 16, 2015 10:15 am

    Get a 12AU7-12XXX type socket convertor......to a 6SN7 if you wont a super tube sound!
    None of the small type tubes have the Big Tone of the 6sn7.....Not that I have had in over 40 years..
    Just one mans finding....
    but have fun with tube sound....






    Thanks Bob..............

    sKiZo

    Posts : 1285
    Join date : 2013-04-01
    Location : Michigan USA

    Well, this is interesting ...

    Post by sKiZo on Sun Feb 22, 2015 9:07 pm

    http://translate.google.com/translate?js=n&prev=_t&ie=UTF-8&tl=en&u=http%3A%2F%2Fwww.mif.pg.gda.pl%2Fhomepages%2Fjasiu%2Feka%2Fval%2Fecc813.html

    Due to microphonics and noise is not suitable for audio levels with a small signal level.

    I suppose a lot would depend on what's considered a "small signal level" ...

    Hmmmmm ...

    Gregg R.

    Posts : 80
    Join date : 2014-02-20
    Age : 71
    Location : Land of 11,842 Lakes

    Super 12au7: Tungsram E80CC

    Post by Gregg R. on Mon Feb 23, 2015 12:29 am

    sKiZo:

    You might want to try the Tungsram E80CC; it's taller than a conventional 12au7, and draws more heater current. It is the center tube in my avatar. It sounds somewhat clinical for the first 50 hrs., but mellows out over time. I bought mine off eBay from the Tubemazestore for $25.

    Tungsram E80CC

    Another variation is the Phillips E80CC. It is more refined and mellow, but much more costly:

    Phillips E80CC

    Both variations are very dynamic and highly resolving; they are also relabeled as Valvo, Siemens, Amperex, etc. Also known as the 6085 or CV5989. Gain is a little higher than a 12au7.

    Nikolay at the Tubemazestore on eBay does accept returns just because you don't care for the sound. I recently returned 2 of a matched quad of RCA 5963s simply because they didn't sound as good as the pair I kept. I don't believe that Parts Connexion accepts returns unless defective.

    Gregg R.

    skriefal

    Posts : 116
    Join date : 2011-09-20
    Location : Utah, USA

    Re: "Super" 12AU7?

    Post by skriefal on Mon Feb 23, 2015 1:27 am

    Isn't the E80CC closer to a 12AT7 than to a 12AU7?

    sKiZo

    Posts : 1285
    Join date : 2013-04-01
    Location : Michigan USA

    Re: "Super" 12AU7?

    Post by sKiZo on Mon Feb 23, 2015 5:39 pm

    I'm currently leaning more towards the "I already have too many choices" camp. Wanna have some fun, try figuring out the possible combinations based on the drivers you have and the number of possible combinations for rolling in a unique set of three into three random sockets.

    Currently comes up to around 3000 here, so that should keep me busy for a while ...

    * Was just listening to Kompendium Beneath the Waves with the current driver set ... a GE 12BH7 in the center, flanked with a matched set of Westinghouse Star 5 5963's, and trying to imagine how it could possibly sound better ... excellent rock opera btw ...

    Sponsored content

    Re: "Super" 12AU7?

    Post by Sponsored content Today at 1:21 am


      Current date/time is Mon Sep 26, 2016 1:21 am