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


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    12AU7 type tubes .. Great driver tubes for tube audio amps ...

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    Post by Bob Latino Mon Dec 12, 2016 9:42 am

    All the VTA amps use 12AU7 type driver tubes. These are great tubes for a driver circuit that have relatively low gain and generally very low noise levels. For the past 4 years all the VTA amps (kit or wired) have been shipped (for those that want a tube set) with USA made (GE, RCA or Sylvania) 12AU7 type driver tubes. These also include 5963, 5814 and 6189 driver tubes which are military/industrial versions of a 12AU7. I find that ANY of the USA made tubes to be more reliable AND generally better sounding than modern made 12AU7 tubes. A Greek web site (http://tubeamplifiers.simplesite.com) did a comparison of a number of different 12AU7 driver tubes that you may find interesting to read. Link below ...

    12AU7 driver tube comparison

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    Post by BNR_1 Mon Dec 12, 2016 4:58 pm

    I saw the write up on the 12AU7 and it is a copy from Brent Jessee's webpage.
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    Post by OneyedK Wed Dec 14, 2016 7:08 am

    Interesting read...

    But what I really want to know is how the current production 12AU7's are doing:

    Shuguang 12AU7A / ECC82-C
    JJ Electronic ECC82 / 12AU7
    JJ Electronic ECC802S / 12AU7
    JJ Electronic ECC82 / 12AU7 Gold
    JJ Electronic ECC802S / 12AU7 Gold
    Elektro Harmonix 12AU7 / ECC82
    Elektro Harmonix 12AU7 / ECC82 Gold-pin
    Mullard (Russia) 12AU7 / ECC82
    Gold Lion (Genalex Russia)12AU7 / ECC82
    Psvane 12AU7-T-MII/2
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    Post by Dave_in_Va Wed Dec 14, 2016 10:14 am

    I like that high quality NOS 12AU7s are still pretty inexpensive, especially compared to high end 12AX7s and the dreaded 6922 (in the PH 14).
    I think the price of NOS takes the newer Russian and Chinese tubes out of consideration.
    Just an opinion.
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    Post by peterh Wed Dec 14, 2016 2:42 pm

    OneyedK wrote:Interesting read...

    But what I really want to know is how the current production 12AU7's are doing:

    Shuguang 12AU7A / ECC82-C
    JJ Electronic ECC82 / 12AU7
    JJ Electronic ECC802S / 12AU7
    JJ Electronic ECC82 / 12AU7 Gold
    JJ Electronic ECC802S / 12AU7 Gold
    Elektro Harmonix 12AU7 / ECC82
    Elektro Harmonix 12AU7 / ECC82 Gold-pin
    Mullard (Russia) 12AU7 / ECC82
    Gold Lion (Genalex Russia)12AU7 / ECC82
    Psvane 12AU7-T-MII/2
    JJ ecc82 is doing well, thank you.
    When one 5963 developed a hum i replaced all 3 in my vta-70. And as i have an ample
    supply of jj i choosed them :-)
    All JJ is made in slovakia ( member of EU, middle of europe) The factory and some staf
    is former Tesla Prague, tube origins too.
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    Post by Dahlberg Wed Dec 14, 2016 2:49 pm

    Would the 6n2p fit among these, not sure about the filament arrangement ?
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    Post by OneyedK Wed Dec 14, 2016 2:55 pm

    Dahlberg wrote:Would the 6n2p fit among these, not sure about the filament arrangement ?
    6N2P's are more or less equivalent for 12AX7, with a different heater pinout.

    I don't think there is a Russian equivalent for the 12AU7.
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    Post by OneyedK Wed Dec 14, 2016 3:00 pm

    peterh wrote:JJ ecc82 is doing well, thank you.  And as i have an ample
    supply of jj i choosed them :-)
    Good to know!
    I use the JJ ECC83S most of the time (buy a "boatload", measure and match) whenever I need a 12AX7/ECC83.
    Guess I can do the same with the ECC82's.

    Any benefit in choosing the JJ ECC802S?
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    Post by peterh Wed Dec 14, 2016 3:58 pm

    OneyedK wrote:
    peterh wrote:JJ ecc82 is doing well, thank you.  And as i have an ample
    supply of jj i choosed them :-)
    Good to know!
    I use the JJ ECC83S most of the time (buy a "boatload", measure and match) whenever I need a 12AX7/ECC83.
    Guess I can do the same with the ECC82's.

    Any benefit in choosing the JJ ECC802S?

    As far as i have seen 802/803, the longplate variant, is preferred by guitar folks due
    to their greater stability and resistance to microphonics. A valuable feature when
    operated inside a combo amp.

    Soundwise i see no differences.

    As for ecc83, the ECC83MG has less spread in parameters, seem to be tighter tolerances.
    No need for matching and better predictability ( they are all alike :-), this is what
    i suggest for hifi.
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    Post by OneyedK Wed Dec 14, 2016 5:02 pm

    peterh wrote:As far as i have seen 802/803, the longplate variant, is preferred by guitar folks due
    to their greater stability and resistance to microphonics. A valuable feature when
    operated inside a combo amp.
    I only have experience with the 803, they tend to bleed hum from the heaters into the circuit (same problem with the Sovtek LPS),
    so I could not use them in high gain guitar amps.  The regular 83S doesn't have that problem.
    I wonder if the same is true for the 82/802???

    peterh wrote:As for ecc83, the ECC83MG has less spread in parameters, seem to be tighter tolerances.
    No need for matching and better predictability ( they are all alike :-), this is what
    i suggest for hifi.
    That's great info, gotta keep that in mind when my stash diminishes Embarassed
    Good to hear the MG has less spread, it certainly is a problem with the regular 83S...
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    Post by eickmewg Thu Dec 15, 2016 7:22 am

    My Transcendent Sound Grounded Grid preamp kit came with JJ ECC82 tubes. When I was having trouble finding quiet 12AU7 tubes for my ST-120, I put the JJ's in it. They are virtually silent and sound very good to my ear. Not bad for a $10 tube. Much better than the pricey Mullard CV4003 tube I got from Upscale Audio for the center driver position.
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    Post by Dahlberg Fri Jan 13, 2017 9:28 am

    Here's a guy who has made some comparisons, scroll down a bit on the page to post 53.

    http://www.head-fi.org/t/763045/review-wa7-lcd-2f-dac-shoot-out-tube-guide-updated/45
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    Post by Bob Latino Fri Jan 13, 2017 10:03 am

    Dahlberg wrote:Here's a guy who has made some comparisons, scroll down a bit on the page to post 53.

    http://www.head-fi.org/t/763045/review-wa7-lcd-2f-dac-shoot-out-tube-guide-updated/45

    Thanks for the link .. When I get some time I will pull the Mullard CV4003's out of the front position of my M-125's and try and get hold of some of the other tubes that are listed. The nice thing about 12AU7 type tubes is that there is still a wide variety of US, British and German NOS types available. Yes - Like all NOS tubes, they are getting pricey but they are still available ..

    Bob
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    Post by Jim McShane Fri Jan 13, 2017 2:11 pm

    I've posted many times on other forums what a steal the new reissue Tung-Sol 12AU7 is. It's a STEAL for the price and is every bit as good or better than much of the old stock. I am fortunate that I get a lot of feedback from people who use the tube, and it's a tube I'd use in my own gear for sure. The link posted by Dahlberg has a review that is pretty darn close to exactly what I'd write.

    The same goes for the Genalex reissue B749/12AU7. I get lots of rave reviews about it and it has proven to be VERY reliable in addition.
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    Post by corndog71 Fri Jan 13, 2017 2:59 pm

    For those who think the 6DJ8/6922 are bad tubes I invite you to read this article.

    http://www.tubeaudiostore.com/suitof6dfora.html
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    Post by Dahlberg Sat Jan 14, 2017 9:49 am

    I have a specific plan for finding a tube for the front tube position that
    exels in precision and dynamic performace in the bass region.
    I'm not using the amps outside of 65-350hz so it's fairly specialised.
    I'm using Sylvania Jan 5814A in both positions now and the lowest bass
    response has realistic level and a beautiful tone on acoustic bass.
    I feel it's a little bit rounded of listening to for instance "Yello-Touch-Petro Oleum",
    there is a repeting subsonic decay of the drums that's simply brutal when
    everything works as it should. Imagine a brutaly vibrating wave beneth the
    floorboards moving from 1 meter behind the speakers to and under the sofa
    your sitting in repeting itself Twisted Evil Now it's there but not as brutal as I
    have heard it before, the location is above the floor and a bit diffuse.
    I have bought some tubes aimed at the refinement of this area.
    Level of bass is adjustable but resolution and dynamics has to come from elsewhere.
    Based solely on the opinion of others I came up with , Tungsol 12au7 (new),
    RCA clear tops 12au7, Philips JAN 5963 and RCA 5963.
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    Post by Kentley Sat Jan 14, 2017 10:20 am

    Dahlberg - I sounds to me as if you need to address some room acoustic issues directly, rather than trying to solve the problem with refinement of driver tubes. Your description of the bass rumble (65-80 hZ??) is very common and is something I've had to deal with myself. First - isolation of whichever speaks are producing culprit tones from any resonance with the floor, which I assume is hardwood. Isolation platforms are fairly cheap and very effective. Second, bass diffusion under the couch, which can actually be effected at no cost by filling the space with magazines, books, or tightly-bound bundles of newspaper. Also the area behind those speakers should probably be damped. As well, some refinement of that crucial crossover point of 65 hZ might be accomplised by electronic tweaks. What you have is an excitation of inherent room bass nodes. 'Tis a beech to solve, but you can do it. But expecting tube rolling to accomplish the necessary amelioration is unrealistic.
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    Post by Dahlberg Sat Jan 14, 2017 11:25 am

    Actually this is not uncontroled bass rumble, it's a very clean and
    well defined tone. It's easyly followed both in location and decay.
    If you listen to it with headphones it's also there but not with the
    same physical impact. It starts at ~40s, follow the decay of the drums.
    The room/speakers has the abbility to produce a very clean bassresponse
    to well below 20hz. It's not that far of so I'm quite optimistic.
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    Post by LeGrace Fri Jan 20, 2017 3:19 pm

    Dahlberg wrote:I have a specific plan for finding a tube for the front tube position that
    exels in precision and dynamic performace in the bass region.
    I'm not using the amps outside of 65-350hz so it's fairly specialised.
    I'm using Sylvania Jan 5814A in both positions now and the lowest bass
    response has realistic level and a beautiful tone on acoustic bass.
    I feel it's a little bit rounded of listening to for instance "Yello-Touch-Petro Oleum",
    there is a repeting subsonic decay of the drums that's simply brutal when
    everything works as it should. Imagine a brutaly vibrating wave beneth the
    floorboards moving from 1 meter behind the speakers to and under the sofa
    your sitting in repeting itself Twisted Evil Now it's there but not as brutal as I
    have heard it before, the location is above the floor and a bit diffuse.
    I have bought some tubes aimed at the refinement of this area.
    Level of bass is adjustable but resolution and dynamics has to come from elsewhere.
    Based solely on the opinion of others I came up with , Tungsol 12au7 (new),
    RCA clear tops 12au7, Philips JAN 5963 and RCA 5963.

    Your idea to use M125 amps for range 65-350 hz is an interesting one. As you are obviously very knowledgeable, I decide to also investigate this possibility in my system. I do not have ability to dial in the frequency to exactly match, but I am not so far off, 80-400hz. So now < 80 Hz is on subwoofer that has its own 500w built in SS amp, 80-400 hz is 250 mm bass driver of my Tannoy D700 connected to M125's, and >400 Hz is by my Marantz 100/ch SS integrated.

    Before I have both the floor standers and the sub covering bottom range, but the bass is cleaner and stronger now that there is no competition between them anymore. I notice improvement in sound stage as well, more expansive. Next I am thinking to roll my 6550's back in. Please share if you find improved driver tube.

    Anyway, thank you Dahlberg! I am very happy with the results!
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    Post by Dahlberg Fri Jan 20, 2017 8:27 pm

    LeGrace wrote:
    Dahlberg wrote:I have a specific plan for finding a tube for the front tube position that
    exels in precision and dynamic performace in the bass region.
    I'm not using the amps outside of 65-350hz so it's fairly specialised.
    I'm using Sylvania Jan 5814A in both positions now and the lowest bass
    response has realistic level and a beautiful tone on acoustic bass.
    I feel it's a little bit rounded of listening to for instance "Yello-Touch-Petro Oleum",
    there is a repeting subsonic decay of the drums that's simply brutal when
    everything works as it should. Imagine a brutaly vibrating wave beneth the
    floorboards moving from 1 meter behind the speakers to and under the sofa
    your sitting in repeting itself Twisted Evil Now it's there but not as brutal as I
    have heard it before, the location is above the floor and a bit diffuse.
    I have bought some tubes aimed at the refinement of this area.
    Level of bass is adjustable but resolution and dynamics has to come from elsewhere.
    Based solely on the opinion of others I came up with , Tungsol 12au7 (new),
    RCA clear tops 12au7, Philips JAN 5963 and RCA 5963.

    Your idea to use M125 amps for range 65-350 hz is an interesting one. As you are obviously very knowledgeable, I decide to also investigate this possibility in my system. I do not have ability to dial in the frequency to exactly match, but I am not so far off, 80-400hz. So now < 80 Hz is on subwoofer that has its own 500w built in SS amp, 80-400 hz is 250 mm bass driver of my Tannoy D700 connected to M125's, and >400 Hz is by my Marantz 100/ch SS integrated.

    Before I have both the floor standers and the sub covering bottom range, but the bass is cleaner and stronger now that there is no competition between them anymore. I notice improvement in sound stage as well, more expansive. Next I am thinking to roll my 6550's back in.  Please share if you find improved driver tube.  

    Anyway, thank you Dahlberg! I am very happy with the results!  

    I'll have to get back to you about your setup, is there a more on topic thread where we can discuss
    this by the way ? I have recived both sets of the 5963 tubes and have tried the RCA ones a bit.
    One tube was quite noisy (have tried three) but they have a real nice tone and they differ a bit in
    their lowest bass respons from the 5814A's. Not that much but there is a difference at least.
    For better or worse ?
    They have just been in for a few hours so I'll have to wait with any conclusions for now. There are
    more tubes coming in as well soo...This is fun Very Happy
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    Post by LeGrace Sat Jan 21, 2017 9:46 am

    Yes it would be better to should start new thread, which I am about to do!
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    Post by Dahlberg Wed Jan 25, 2017 6:52 am

    I plugged in the 12au7 Tungsol new production five minutes ago. It has the lowest noise so
    far, measured 2,5mV ac on speaker outputs. Very Happy None other has been under 3,5mV so far.
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    Post by wgallupe Wed Jan 25, 2017 1:50 pm

    Dahlberg wrote:I plugged in the 12au7 Tungsol new production five minutes ago. It has the lowest noise so
    far, measured 2,5mV ac on speaker outputs. Very Happy None other has been under 3,5mV so far.

    Looking forward to your impressions on how they sound compared to the others you have tried.
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    Post by Dahlberg Wed Jan 25, 2017 5:43 pm

    wgallupe wrote:
    Dahlberg wrote:I plugged in the 12au7 Tungsol new production five minutes ago. It has the lowest noise so
    far, measured 2,5mV ac on speaker outputs. Very Happy None other has been under 3,5mV so far.

    Looking forward to your impressions on how they sound compared to the others you have tried.

    First impression wasn't that good. One day might be a little to early to judge them though, they are brand new so.... Neutral
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    Post by pedrocols Wed Jan 25, 2017 7:05 pm

    I just purchased a matched pair of Raytheons 12au7(pretty cheap). To my ears they do have good bass and not too busy on the higher frequencies. Definitely less roll of than the Mullard cv4003. Midrange however is very good. I like them!
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