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    Upgrade Pas 3 or not?

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    poconoman

    Posts : 106
    Join date : 2013-01-17

    Upgrade Pas 3 or not?

    Post by poconoman on Sat Feb 09, 2013 6:12 pm

    Hello all,

    I was able to grab a Pas 3 on the Bay. It's completely stock except the 12AX7 tubes. Sovteks. (yeah, I know) Anyway, the original owner says it works perfectly. I know if any mods would decrease the value, but what is the failure rate on the selenium rec? Leave it or play it safe and change?

    Thanks

    GP49

    Posts : 735
    Join date : 2009-04-30
    Location : East of the sun and west of the moon

    Re: Upgrade Pas 3 or not?

    Post by GP49 on Sun Feb 10, 2013 1:03 am

    A failed selenium rectifier will result in slow warmup and poorly defined sound. Most
    properly functioning PAS I see nowadays have silicon rectifier diodes soldered onto the
    existing selenium rectifier, effectively using the selenium device as a terminal strip.
    Practically all selenium rectifiers fail high-resistance or open-circuit, so paralleling
    silicon rectifiers across them should work just fine.

    poconoman

    Posts : 106
    Join date : 2013-01-17

    Re: Upgrade Pas 3 or not?

    Post by poconoman on Sun Feb 10, 2013 9:16 am

    GP49 wrote:A failed selenium rectifier will result in slow warmup and poorly defined sound. Most
    properly functioning PAS I see nowadays have silicon rectifier diodes soldered onto the
    existing selenium rectifier, effectively using the selenium device as a terminal strip.
    Practically all selenium rectifiers fail high-resistance or open-circuit, so paralleling
    silicon rectifiers across them should work just fine.

    Thanks for the reply!

    Where exactly do I solder the diode? Any pics, diagrams?

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