The Dynaco Tube Audio Forum

Dedicated to the restoration and preservation of all original Dynaco tube audio equipment - Customer support for Dynaco VTA tube amp kits, all Tubes4hifi.com products and all Dynakitparts.com products


    PAS Filament current

    Share

    Scot_B

    Posts : 8
    Join date : 2013-06-26
    Age : 59
    Location : North Dallas, Texas

    PAS Filament current

    Post by Scot_B on Sat Sep 28, 2013 7:05 pm

    I see that I can save on current consumed by switching up to the LED mod vs the standard bulb. Seems like a good move rather than replacing the old burned out bulb.  This has me thinking,  I don’t use the phono or tape inputs that belong to the PC-6 card, could I get away with pulling the 12AX7’s on it without modifying the PAS and achieve even better filament current savings and not adversely affect the line card performance ?

    Bob Latino
    Admin

    Posts : 2374
    Join date : 2008-11-26
    Location : Massachusetts

    Re: PAS Filament current

    Post by Bob Latino on Sat Sep 28, 2013 7:22 pm

    You could pull those 12AX7 tubes on the phono board - BUT - then the other two line stage 12AX7's would be working at somewhat higher voltages which *could* shorten their life. What I might do is put a couple of cheapie Chinese 12AX7's on the phono board and save the better (Telefunken original ?) 12AX7's that are on the phono board now.

    Bob

    PeterCapo

    Posts : 380
    Join date : 2008-12-05

    Re: PAS Filament current

    Post by PeterCapo on Sun Sep 29, 2013 4:09 pm

    As I recall, if you pull the phono board tubes, you'll need to add a ground reference to the tubes on the line card at eyelet 20.

    There's another issue.  If you remove the tubes from the phono board and replace the pilot lamp with a diode, yes, the B+ will be higher - closer to or possibly exceeding the voltage rating of the quad cap.


    Last edited by PeterCapo on Mon Sep 30, 2013 7:03 pm; edited 1 time in total

    Scot_B

    Posts : 8
    Join date : 2013-06-26
    Age : 59
    Location : North Dallas, Texas

    Re: PAS Filament current

    Post by Scot_B on Sun Sep 29, 2013 4:24 pm

    Seemed like a good idea... I think I'll leave the tubes alone, and just replace the burned out bulb with the LED kit...

    Thanks for the responses

    Scot

    Sponsored content

    Re: PAS Filament current

    Post by Sponsored content Today at 1:20 am


      Current date/time is Mon Sep 26, 2016 1:20 am