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    New VTA-70 Amp

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    mazeeff

    Posts : 122
    Join date : 2014-01-06
    Age : 61
    Location : Grand Rapids, Michigan, USA

    New VTA-70 Amp

    Post by mazeeff on Tue Sep 08, 2015 1:15 pm

    I just purchased this amp on Audiogon. Does anyone recognize it? The person that I purchased it from, was not the builder. It looks to have the 1st generation of low gain board, and came with three NOS Mullard CV4003's. I will receive it, in a couple of days. My 1967 ST-70 was starting to exhibit power supply problems, and I am looking forward to giving this one a try.

    Mike




    audiobill

    Posts : 270
    Join date : 2014-03-13
    Location : Philadelphia

    Re: New VTA-70 Amp

    Post by audiobill on Tue Sep 08, 2015 5:43 pm

    Interesting, looks like an original chassis with dynakit transformers and a vta board. Note those two bias pots aren't connected.....

    mazeeff

    Posts : 122
    Join date : 2014-01-06
    Age : 61
    Location : Grand Rapids, Michigan, USA

    Re: New VTA-70 Amp

    Post by mazeeff on Tue Sep 08, 2015 6:18 pm

    The bias pots were installed, just to fill the holes, since the amp does not have the Triode kit installed. I believe that the entire kit is a Latino VTA-70. The prior owner has all the build manuals and such. It is interesting that these Latino amps are getting multiple owners, as the years go on!

    Mike

    Guest
    Guest

    Re: New VTA-70 Amp

    Post by Guest on Tue Sep 08, 2015 7:02 pm

    its an early version VTA driver board, it has the 4x individual biasing for each power tube.
    Looks like the bias test point are nicely provided between each set of power tubes.
    Nice set of Russian PIO's!
    You could always remove the old bias potentiometers and install the pentode/triode switches in their place. Will need some re wiring, but nothing too complicated.

    mazeeff

    Posts : 122
    Join date : 2014-01-06
    Age : 61
    Location : Grand Rapids, Michigan, USA

    Re: New VTA-70 Amp

    Post by mazeeff on Tue Sep 08, 2015 7:16 pm

    Just ordered the Triode kit, and it will be installed soon! Any idea what brand the green caps are? I will not get the amp for a couple of days! These amps are like folk art. Everyone adds their own little touches!

    Mike

    Bob Latino
    Admin

    Posts : 2414
    Join date : 2008-11-26
    Location : Massachusetts

    Re: New VTA-70 Amp

    Post by Bob Latino on Tue Sep 08, 2015 7:26 pm

    mazeeff wrote:Just ordered the Triode kit, and it will be installed soon! Any idea what brand the green caps are? I will not get the amp for a couple of days! These amps are like folk art. Everyone adds their own little touches!

    Mike

    The gray colored caps on your amp are the Russian K40-Y PIO caps. The green colored caps are the Russian K42-Y PIO caps .. BOTH are excellent quality and dead reliable caps ...

    Bob

    mazeeff

    Posts : 122
    Join date : 2014-01-06
    Age : 61
    Location : Grand Rapids, Michigan, USA

    Re: New VTA-70 Amp

    Post by mazeeff on Wed Sep 09, 2015 10:04 am

    Bob. Based on what you see, can you estimate a range of possible build dates?

    Mike

    Bob Latino
    Admin

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    Join date : 2008-11-26
    Location : Massachusetts

    Re: New VTA-70 Amp

    Post by Bob Latino on Wed Sep 09, 2015 10:08 am

    mazeeff wrote:Bob. Based on what you see, can you estimate a range of possible build dates?

    Mike

    Hi Mike,

    Build dates ? Can you explain this in more detail ? I don't understand what you mean here ?

    Bob

    mazeeff

    Posts : 122
    Join date : 2014-01-06
    Age : 61
    Location : Grand Rapids, Michigan, USA

    Re: New VTA-70 Amp

    Post by mazeeff on Wed Sep 09, 2015 10:39 am

    Sorry. Based on this being a 1st generation of the "low gain" board, when were these types of boards shipped? I am not sure when the board with the LM334 was introduced, but this kit would appear to have been shipped prior to that.

    Mike

    Bob Latino
    Admin

    Posts : 2414
    Join date : 2008-11-26
    Location : Massachusetts

    Re: New VTA-70 Amp

    Post by Bob Latino on Wed Sep 09, 2015 10:53 am

    Mike,

    The VTA CCS board was introduced by Roy in early 2012 so that board is at least 3 years old .. NOTE - That amp is not one of the "VTA ST-70 amps kits" from me. That amp has the Dynakitparts transformer so it may be a Dynakitparts stock type amp modified with a VTA driver board. That amp also has white ceramic tube sockets. I never shipped a VTA ST-70 amp kit with ceramic tube sockets.

    Bob

    mazeeff

    Posts : 122
    Join date : 2014-01-06
    Age : 61
    Location : Grand Rapids, Michigan, USA

    Re: New VTA-70 Amp

    Post by mazeeff on Wed Sep 09, 2015 11:28 am

    Interesting! It must have either been one of the the Dynakit kits with a 7199 board, converted to VTA low gain later, or Individual Dynakit parts with the VTA driver. Are the Dynakit transformers and chassis different from the Latino kit? I have always been a little confused between the Dynakit products and the Tubes4hifi products!

    Mike

    Tube Nube

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    Age : 53
    Location : Calgary, AB

    Re: New VTA-70 Amp

    Post by Tube Nube on Wed Sep 09, 2015 12:47 pm

    As I understand it, the Latino transformers are beefed up relative to the original spec trannies. Further, iirc, you would want the updated transformers if you were going to run bigger power tubes than el34 tubes. Tubes such as the KT 77, KT 88, etc.

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