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    Softball question,Pas 3

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    badtuna

    Posts : 6
    Join date : 2011-04-19

    Softball question,Pas 3

    Post by badtuna on Fri May 10, 2013 4:26 pm



    Hello.My first tube preamp.It's a Pas3 it looks like no mods have been done.
    The plan is to leave it stone stock.Can you hook up a cd deck to any of the imputs.
    Thanks in advance for not rolling your eyes or audibly sighing.

    hawaii.ken

    Posts : 157
    Join date : 2012-01-31

    Re: Softball question,Pas 3

    Post by hawaii.ken on Fri May 10, 2013 4:38 pm

    You can hook your CD deck to the "Spare" input.

    peterh

    Posts : 641
    Join date : 2012-12-25
    Location : gothenburg, sweden

    Re: Softball question,Pas 3

    Post by peterh on Fri May 10, 2013 4:45 pm

    badtuna wrote:

    Hello.My first tube preamp.It's a Pas3 it looks like no mods have been done.
    The plan is to leave it stone stock.Can you hook up a cd deck to any of the imputs.
    Thanks in advance for not rolling your eyes or audibly sighing.
    A very "mild" mod is to connect 2 1n4007 diodes in paralell with the se rectifier. You can use the se as mounting points.
    Se ( selenium) rectifiers tend to increase resistance thus reduce the filament voltage, this will
    give a dull sound. Measure the filament DC , if it's below 20V you have this problem.


    badtuna

    Posts : 6
    Join date : 2011-04-19

    Re: Softball question,Pas 3

    Post by badtuna on Fri May 10, 2013 8:03 pm


    Thanks for the comments.It sounds OK considering it's age,to me that is.
    I'm will try some of the upgrades but I don't to do anything I can't put back
    as it was.I think an original one these will be hard to find down the road.

    peterh

    Posts : 641
    Join date : 2012-12-25
    Location : gothenburg, sweden

    Re: Softball question,Pas 3

    Post by peterh on Sat May 11, 2013 2:28 am

    badtuna wrote:
    Thanks for the comments.It sounds OK considering it's age,to me that is.
    I'm will try some of the upgrades but I don't to do anything I can't put back
    as it was.I think an original one these will be hard to find down the road.
    I'm happy that you will save one PAS3 for future generations. They are more and more scarce now.

    For those that wants to mod, rob has given an excellent advice in another thread, start with a
    pat-4 ( the transistorized one), clean all inside and mount tube hardware there. PAT-4 are plentiful
    cheap and noone will miss them ( yet).

    GP49

    Posts : 717
    Join date : 2009-04-30
    Location : East of the sun and west of the moon

    Re: Softball question,Pas 3

    Post by GP49 on Sat May 11, 2013 1:15 pm

    You can hook up a CD player to ANY of the following:

    SPARE
    FM-AM
    FM-MPX

    SPARE is probably the best, just because of possible confusion by uninformed users ("You hooked
    up your CD player to FM-AM? WHY?" but all are electrically identical. I had a reel-to-reel
    deck connected to my SPARE input (but it now has a computer line output hooked to it), so FM-AM
    is where the CD player has been for many years. FM-AM does NOT interact with FM-MPX; they are entirely
    separate.

    j beede

    Posts : 316
    Join date : 2011-02-07
    Location : California

    Re: Softball question,Pas 3

    Post by j beede on Sat May 11, 2013 3:54 pm

    I have never experienced crosstalk as I had with the PAS (PAS-2) series of preamps--I am talking about crosstalk between inputs, not L/R channels. I had my cable box connected to an unused input and could here TV audio as plain as day when I was using the phono input for music. I don't think the ganged selector switch in the PAS-3 is any different than what was in my PAS-2. I no longer have that preamp but if I recall correctly, it used simple hookup wire--not coaxial cable--between the rear panel and the selector switch.

    peterh

    Posts : 641
    Join date : 2012-12-25
    Location : gothenburg, sweden

    Re: Softball question,Pas 3

    Post by peterh on Sat May 11, 2013 6:13 pm

    j beede wrote:I have never experienced crosstalk as I had with the PAS (PAS-2) series of preamps--I am talking about crosstalk between inputs, not L/R channels. I had my cable box connected to an unused input and could here TV audio as plain as day when I was using the phono input for music. I don't think the ganged selector switch in the PAS-3 is any different than what was in my PAS-2. I no longer have that preamp but if I recall correctly, it used simple hookup wire--not coaxial cable--between the rear panel and the selector switch.
    That's why the unused inputs are shorted to ground.
    Did you replace the dynaco selector with something that does not ground unused inputs ?

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