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    VTA PAS3-Z and I/O Back Panel Wiring



    Posts : 11
    Join date : 2010-08-10
    Age : 70
    Location : Flossmoor, Illinois USA

    VTA PAS3-Z and I/O Back Panel Wiring

    Post by pwsnyder on Wed Oct 06, 2010 1:13 am

    I'm more than a little confused about the wiring schema between the improved VTA I/O back panel strip and the PAS3-Z PC-6 phono board. My version of the PAS3-Z phono board (I understand there are a number of versions) has one 8 pin connector at the end nearest the volume control and a 4 pin connector closest to the back panel. In the photos I received w/ the kit it is clear that the twisted pair wiring for all inputs have the ground soldered at the phono input jack - but not connected at the selector switch. This I understand. However, I am confused by the photos that show shielded cable running from the phono jacks to the 8 pin connector on the phono board. In the photos it APPEARS that at the I/O board end the center conductor and shield are soldered to the center and ground tabs on the L/R jacks and then are attached to the IN1 and IN2 AND also to ground. Am I seeing this correctly? Or, are the shields left disconnected at the phono jack end???

    Thanks for the help!

    Posts : 1463
    Join date : 2008-11-30

    PAS3-Z phono wiring

    Post by tubes4hifi on Wed Oct 06, 2010 1:35 pm

    yes, the photo is correct -top photo of final wiring on this page about 80% down the page -
    that's an older version, newer version has a 4 pin header right next to the phono input jacks.
    Anyway, photo is correct for your version. Signal and ground connect to the PCB, they have to.
    Otherwise the signal wouldn't have a reference against which to be amplified.
    The OUTPUT signal and ground are twisted pairs, which the grounds do NOT connect to the selector.
    I know this can be difficult to understand, but the grounds are actually all connected thru the power supply, which makes the power supply the star ground. This is what keeps hum and ground loops from forming.
    Also a correction to your statement, all input grounds are connected together at the OUTPUT jack, not the phono jack, the phono jack should be totally isolated from all other connections.
    Hope that answers your question, if not, contact me directly at Roy


    Posts : 11
    Join date : 2010-08-10
    Age : 70
    Location : Flossmoor, Illinois USA

    I stand corrected

    Post by pwsnyder on Fri Oct 08, 2010 12:53 am

    Roy, I didn't mean actual "ground" - but the ground tab on the rca jack. Sorry for the confusion.

    Thank-you for the response. The wiring scheme is now much clearer!

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    Re: VTA PAS3-Z and I/O Back Panel Wiring

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