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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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    NEW TO ME PAS-3X QUESTIONS

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    moodyj2000


    Posts : 12
    Join date : 2023-01-18

    NEW TO ME PAS-3X QUESTIONS Empty NEW TO ME PAS-3X QUESTIONS

    Post by moodyj2000 Tue Jan 24, 2023 11:15 am

    Just purchased a PAS-3X in untouched condition. I've been reading the boards about the RIAA mod to PC-6 and other issues with PC-5. Trying to make a list of needed modifications. The first on my list is the selenium rectifier. My question is this. Is it worth changing out parts on the existing boards or just purchase new replacement boards for PC-5 and PC-6 along with the power supply?

    I have seen the replacement boards on Curcio Audio and Erhard Audio. There is definite cost implications on going that route and being new to Dynaco I am not familiar with either companies reliability or the final performance of their products.

    Should I make modifications to the existing PCB's and power supplies or work up to investing on changing out the insides?

    Thanks,
    Jason
    peterh
    peterh


    Posts : 1718
    Join date : 2012-12-25
    Location : gothenburg, sweden

    NEW TO ME PAS-3X QUESTIONS Empty Re: NEW TO ME PAS-3X QUESTIONS

    Post by peterh Tue Jan 24, 2023 1:54 pm

    moodyj2000 wrote:Just purchased a PAS-3X in untouched condition.  I've been reading the boards about the RIAA mod to PC-6 and other issues with PC-5.  Trying to make a list of needed modifications.  The first on my list is the selenium rectifier.  My question is this.  Is it worth changing out parts on the existing boards or just purchase new replacement boards for PC-5 and PC-6 along with the power supply?

    I have seen the replacement boards on Curcio Audio and Erhard Audio.  There is definite cost implications on going that route and being new to Dynaco I am not familiar with either companies reliability or the final performance of their products.

    Should I make modifications to the existing PCB's and power supplies or work up to investing on changing out the insides?

    Thanks,
    Jason
    There is a lot of "hype" and mis-understanding about this amp. Most ( all ?) of them is unfounded
    and will have bad side effects.

    Removing the tonecontrols on a PAS3X is one such misunderstanding it's already
    there just turn the pots in middle position.

    Have a look at http://www.audioregenesis.com/
    for someone who actually have been digging deep into this.

    What could be recommended is a "power board" that replaces all electrolytic caps for
    both B+ and filament . z-psu from erhard audio is one such board. Apart from that
    ( and possibly new tubes) normal cleaning and lubing of pot shafts is a good start.

    One issue tat sometimes occur is hum, this is fixed by carefully following the
    cabling layout in the dynaco manual if original components are used. If a "power board"
    is used ( a-psu has exactly the same design as the original, only modern components) then
    short cables on top of the chassies will get the unit dead quiet.



      Current date/time is Thu Feb 02, 2023 12:56 pm