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The Dynaco Tube Audio Forum

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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    Inserting crossover network between PAS 3 and ST 70

    qvr649
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    qvr649


    Posts : 2
    Join date : 2012-09-22
    • Post n°1

    Inserting crossover network between PAS 3 and ST 70 Empty Inserting crossover network between PAS 3 and ST 70

    Post by qvr649 Mon Sep 23, 2013 4:50 am

    Hi,

    I just acquired a stock Dyna PAS 3X. I hooked it up exactly where my other preamp was,i.e connected to a subwoofer crossover network/amp (Kinergetics Research SW-100), crossover output to a stock ST 70. Speakers are a pair of Spica TC 50i. Problem, only the left channel is working. there is no problem with the other preamp! I would appreciate input from anyone who might have experienced similar problem. Thanks for your attention.
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    Bob Latino
    Bob Latino
    Bob Latino
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    Location : Massachusetts
    • Post n°2

    Inserting crossover network between PAS 3 and ST 70 Empty Re: Inserting crossover network between PAS 3 and ST 70

    Post by Bob Latino Mon Sep 23, 2013 9:04 am

    The first thing to check is the the tape/input switch is not dirty. A bad tape/input switch can knock out one or both channels if the contacts inside the switch are dirty. Spray the switch inside the amp with contact cleaner and flip the switch back and forth about 10 times and see if the dead channel comes back to life. If this is not the problem then try spraying the contacts on the selector switch especially the ones with the RED (right channel) wires connected.

    If it is not a contact issue, it could be a number of other different things that could cause the right channel to go out (tubes, bad solder connection, bad part(s) ? To check for a tube issue > Swap the 12AX7 tubes from channel to channel on the line stage board (the board closest to the front of the preamp) to see if the dead channel is now on the left channel.

    Bob
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    qvr649
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    qvr649


    Posts : 2
    Join date : 2012-09-22
    • Post n°3

    Inserting crossover network between PAS 3 and ST 70 Empty Re: Inserting crossover network between PAS 3 and ST 70

    Post by qvr649 Mon Sep 23, 2013 8:39 pm

    Thanks a lot Bob! I will let you know as soon as I get it done.
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    Inserting crossover network between PAS 3 and ST 70 Empty Re: Inserting crossover network between PAS 3 and ST 70

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