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    VTA Upgrades

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    Mikeski

    Posts : 11
    Join date : 2010-10-25

    VTA Upgrades

    Post by Mikeski on Tue Mar 15, 2011 3:49 pm

    I am in the process of ordering the VTA board for my Dynaco-70. I have a preamp so I am looking to get the low gain version. I also plan to get the Russian PIO coupling caps.

    All the different caps have me a little confused though.

    One picture has two different size caps in C13-16. One for C13/14 and another for C15/16, why? Another they are all the same size and blue and another they are bigger and black. what does the value change from 88uf to 334uf do? Other than change the color from blue to black.

    What type of 12AU7 are people using? Is the center tube quality more important than the other two? Like matched sides for that center tube? just any old set of three?

    mikeski

    mantha3

    Posts : 298
    Join date : 2010-11-10

    Re: VTA Upgrades

    Post by mantha3 on Tue Mar 15, 2011 3:59 pm

    I think you have 2 options with the VTA.

    1 - The cap upgrade which is the 4 caps on the top of the VRA behind the 3 tubes. These are a good idea to get for the $$$. Extra Capacitance so ya got juice in reserves (I think that is the theory here)

    Then also on the top you get an .10 uF pair of orange drops... I actually didn't use these and I got some Audio Cap Theta .10uf. These two .10 Caps are on the Signal Path.


    2 - Then under the board you have 4 .22 Coupling Caps. These are where the Russian PIOs sit. These are also in the signal path. I actually am running 4 Jantzen Silver .22 Caps in these 4 spots. These coupling caps impact the sound and you want to get something better then the standard. The PIOs are a great idea.. Or something other that is of a good quality. I think these 4 coupling caps are the most important of the caps on the VTA. Bob Latino or Roy will probably chime in on this... And probably correct mistakes I've made on this... I come here to learn Embarassed

    Have fun! The VTA with the Cap upgrades is a great upgrade.

    My 10 cents on this is to go with the caps.

    Mikeski

    Posts : 11
    Join date : 2010-10-25

    Re: VTA Upgrades

    Post by Mikeski on Tue Mar 15, 2011 4:09 pm

    Thanks for the input. I can understand having a little more in reserve. I was unsure if it did anything for sound. Like more bass umph.

    I did not see an upgrade to move to orange drops. I see them in the pictures at the top of the page but then lower they are smaller and black. Is this another upgrade? I know four on the bottom are replaced by the PIO caps. Should the other 4 be upgraded to something else? Like the orange drops? I believe I saw something in a post that Bob might have put the PIO's in those other 4 spots and saw no difference between them.

    mikeski

    mantha3

    Posts : 298
    Join date : 2010-11-10

    Re: VTA Upgrades

    Post by mantha3 on Tue Mar 15, 2011 4:20 pm

    I bet with the Cap upgrade (The four caps blue/black) you perhaps also get the 4 orange drops.. I think if you don't do the cap upgrade you get the black ones. I think he has a mix of photos where you have the standard caps and then the upgrades...

    I did the cap upgrade and then also did the 4 russian PIOs. I got the orange drops. I use 2 of the .10 uF orange drops on the bottom of the VTA and then opted to try the Audio Cap Theta .10 on top (these are in the signal path) I am sure the sound isn't much better.. Messing with caps can be addictive like tube rolling..

    mantha3

    Posts : 298
    Join date : 2010-11-10

    Re: VTA Upgrades

    Post by mantha3 on Tue Mar 15, 2011 4:23 pm

    PS - you may have a bit more bass umph when you have the amp on loud... Extra capacitance never hurts when kicking up the volume!

    Again... I'm just trying to graduate from "Tube Amps 101"

    Have fun

    Mikeski

    Posts : 11
    Join date : 2010-10-25

    Re: VTA Upgrades

    Post by Mikeski on Tue Mar 15, 2011 4:35 pm

    Thanks Mantha, and I am attempting to use braincells I have not had to use since the mid 70's. I use to know all this. Or at least a good portion of it. I took all the to the component repair knowledge I had and reapplied the troubleshooting knowledge to computers long ago. And now I am just a user of those anymore.

    mikeski

    tubes4hifi
    Admin

    Posts : 1261
    Join date : 2008-11-30

    Re: VTA Upgrades

    Post by tubes4hifi on Tue Mar 15, 2011 9:20 pm

    SOME of the photos on the webpage are fairly old. I used to supply Orange Drops as the standard caps and I believe Bob still does.
    We use the 716P type which are film & foil, not the cheaper 715P type which are metalized film.
    It's been about two years now, I switched to Solens, they are smaller and easier to fit on the board, and sound very good.
    Two of the smaller .10uF's are in the signal path, and the other two are bypass for the phase splitter and not as critical.
    The board will sound great with the standard parts supplied.
    The PIO upgrade and the power supply upgrade caps are the biggest (actually rather small, it's already a great performer) improvements for the money. The PIOs need some burn-in time but will give you more "like you are there" sound, rather than slightly behind a veil curtain.
    I haven't supplied the old blue Xicon caps for over a year, I know supply Nichicon caps which can be black or brown. The upgraded caps are also larger capacity Nichicon brand caps. They will give you more reserve for very loud or deep bass.

    Mikeski

    Posts : 11
    Join date : 2010-10-25

    Re: VTA Upgrades

    Post by Mikeski on Tue Mar 15, 2011 10:03 pm

    Thanks for the info. There's just allot going on in all the pictures. I am looking forward to the updates.

    mikeski

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