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    Tube swapping on the VTA driver board

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    mazeeff

    Posts : 116
    Join date : 2014-01-06
    Age : 61
    Location : Grand Rapids, Michigan, USA

    Tube swapping on the VTA driver board

    Post by mazeeff on Sat Oct 25, 2014 8:34 am

    On the low gain VTA board, do all three 12AU7's respond to the benefits of tube swapping? Should the focus be on the preamp, phase splitters, or all three?

    Mike

    MontanaWay

    Posts : 767
    Join date : 2014-02-06
    Age : 58
    Location : Cameron, Montana

    Re: Tube swapping on the VTA driver board

    Post by MontanaWay on Sat Oct 25, 2014 9:33 am

    the preamp/center tube will have the most effect, but by all means, swap all three and see what differences you will get.

    arledgsc

    Posts : 330
    Join date : 2012-11-30
    Location : SF Bay CA

    Re: Tube swapping on the VTA driver board

    Post by arledgsc on Sat Oct 25, 2014 11:29 am

    Yes! The center tube has greatest influence but I can hear differences with the two phase inverters as well...

    mazeeff

    Posts : 116
    Join date : 2014-01-06
    Age : 61
    Location : Grand Rapids, Michigan, USA

    Re: Tube swapping on the VTA driver board

    Post by mazeeff on Sat Oct 25, 2014 1:43 pm

    Thanks. I will start with the preamp tube.

    Mike

    sKiZo

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

    Re: Tube swapping on the VTA driver board

    Post by sKiZo on Sat Oct 25, 2014 2:33 pm

    Where to start ... scratch



    The center position will have more to do with the soundstage and dynamics, the side drivers with tone and balance. The center should have closely matched triode sections, and the side drivers should just be matched.

    By all means, play around with what you got too. I've got some really good triplets that can change quite a bit of what you're hearing by swapping the same tubes amongst the sockets. You're not only dealing with differences in the tubes themselves, but also in the associated circuitry in the amp, and they've all got their sweet spots. If you really want to have fun, combine tube types in your selection. I had a Marconi 12AU7 driving two Sylvania 5814a's that worked well together. Swapped out the 5814a's for a pair of 12BH7s for a darker sound. Swapped the center for a Tele ECC82 and ended up splitting the difference on tone. Etc. Spin the wheel and prepare to be pleasantly surprised.

    PS ... my collection just got bigger. Got me a triplet of TAD 12AU7a's when I picked up the new KT88's the other day. Figured I couldn't go wrong for the money. They sound good - brighter than the 5963's I've been using but not shrill, and good overall spectrum with no microphonics. Beefy little things - I was surprised to see triple micas. Have to give them an extended listen.

    deepee99

    Posts : 1260
    Join date : 2012-05-23
    Location : Wallace, Idaho

    Re: Tube swapping on the VTA driver board

    Post by deepee99 on Sat Oct 25, 2014 6:50 pm

    Skiz,
    Doesn't look like you have enough tubes yet. Need one more, tee-hee.I am getting a quad of 5963s for no good reason, then will be close to the full complement -- close, that is.

    sKiZo

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

    Re: Tube swapping on the VTA driver board

    Post by sKiZo on Sat Oct 25, 2014 7:42 pm

    Be sure to post back with your impressions ... I kinda sorta stumbled across the matched triplet of Westinghouse Stars that I've been using. Very satisfying ...

    Speaking of TAD 12AU7a's ... Went digging through my driver collection, and these are the only ones with triple micas, other than the 5814a's ...



    They're also labeled as ECC82's.

    deepee99

    Posts : 1260
    Join date : 2012-05-23
    Location : Wallace, Idaho

    Re: Tube swapping on the VTA driver board

    Post by deepee99 on Sun Oct 26, 2014 12:33 pm

    Has anyone had experience with the 5963s in the driver holes of the M-125s?
    Impressions? Am currently using RCA 12BH7As, have never tried anything else.

    Dogstar

    Posts : 81
    Join date : 2014-06-23

    Re: Tube swapping on the VTA driver board

    Post by Dogstar on Sun Oct 26, 2014 1:16 pm

    Which 5963's are you guys talking about? I see on tubedepot.com there is one list for $9.95 each. Is that the one?

    One more question. Tubedepot offers the following options: Balanced Triodes (add $2.00 each), High Gain (add $2.00 each) , Low Noise & Microphonics (add $4.00 each) and Matching (up to 5 tubes) (add $2.00 each) . I can understand Matching being a benefit but are these other extra cost options beneficial or worth paying for?


    deepee99

    Posts : 1260
    Join date : 2012-05-23
    Location : Wallace, Idaho

    Re: Tube swapping on the VTA driver board

    Post by deepee99 on Sun Oct 26, 2014 1:27 pm

    Dogstar wrote:Which 5963's are you guys talking about? I see on tubedepot.com there is one list for $9.95 each. Is that the one?

    One more question. Tubedepot offers the following options: Balanced Triodes (add $2.00 each), High Gain (add $2.00 each) , Low Noise & Microphonics (add $4.00 each) and Matching (up to 5 tubes) (add $2.00 each) . I can understand Matching being a benefit but are these other extra cost options beneficial or worth paying for?


    Early version mil-spec RCAs, black-plate, angled getters, internally matched -- it's a whole different processing than matching power tubes. They fetch about $30 each. Can't speak to Tube Depot's measuring specs. I got tired of ordering tubes from TD that they didn't have in stock and couldn't get.

    sKiZo

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

    Re: Tube swapping on the VTA driver board

    Post by sKiZo on Sun Oct 26, 2014 1:48 pm

    One advantage of the new version lo drive VTA board is it opens up a whole family of tubes that are plug 'n play.

    My favorite 5963's ... Westinghouse??



    Not even sure why I got em ... stumbled across these when looking for some Westinghouse 12AU7's and price looked nice. The Star version is also fairly hard to find. They're full spectrum, a bit more subdued than most 12AU7's and still brighter than your average 12BH7 or 5814 ... perfect for my system.

    BTW ... what works for others may not work for you, but at least you have some basic guidelines to get where you want to be. Lot depends on what you like to listen to, your equipment, and especially for me, the listening environment. Tube choice can have a major impact for tuning the room to your preferences.)

    Oh. Here's the tubes I was actually looking for at the time ...



    A yellow tip denotes low microphonics from the factory. The yellow/red combo is the best of the best. Truth be told, those haven't gotten a lot of airplay, but hey ... it was fun lookin'!

    You should be able to find a real deal on these as they're not all that well known. I see a triplet of NOS Westies on da bay right now at $32. Not Stars though ... the Star is the same tube, but built to military specs. You really don't want any noise or breakdown in a bomb trigger, so they do tend to be more robust and reliable.

    (Pay attention ... you'll be tested on this stuff later!)  study

    eickmewg

    Posts : 38
    Join date : 2014-08-29

    Re: Tube swapping on the VTA driver board

    Post by eickmewg on Sun Oct 26, 2014 1:55 pm

    Bob sent me Sylvania 5963 tubes with my VTA ST120 kit about four months ago. They rather quickly got pretty noisy with some moderate hum. Then I started getting a very loud transient hum about 30 seconds after startup that lasted about 15 seconds and then faded. So, I didn't have very good luck with 5963 driver tubes. I now have a Mullard 12AU7 in the center position and GE 12BH7 tubes for the phase splitters. These have been very quiet and superior to the Sylvania tubes. This combination also sounds very good to my ears.

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