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    A Swedish PAS-3 (and an intro)

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    Soundbrigade

    Posts : 10
    Join date : 2012-08-17
    Age : 63
    Location : Vänersborg, Sweden

    A Swedish PAS-3 (and an intro)

    Post by Soundbrigade on Sat Aug 18, 2012 6:47 am

    Hello all!
    I am the Swedish guy, maybe there are more but in that case, I am a Swedish guy (59+). Having all my life been interested in alectronics, I bought my first tube amp (Heathkit AA-32) in the mid 80's, and have the very last 10 years been almost obsessed, (too obsessed) by tube amps. When I recentely started a job, naming all my amps (90% still unfinished) and marking them with small metal signs (I've picked names of Russian cities), I suddenly realised I have 14 amps on my list - preamps not included, and I forgot the 2C39A and Y10 ... Rolling Eyes
    I spare you any stories from my second hobby, sewing Victorian corsets ... Embarassed

    Last Autumn I happened to mention something on a Swedish forum (hififorum.nu) that resulted in me having gotten a PAS-3 for free (paid for shipping). It lacked mains transformer and the boards were (still are - see for yourself) half populated, or maybe someone started a modification. To be extremely honest, this gift was highly unwanted as I realised I had some major job coming up. Today, almost a year later I have accepted my fate and am looking forward to getting this grand old lady (or gentleman) up and running.

    I had long before I got the amp, already purchased a Swedish wound transformer, made especially for PAS-2/3, and from an advice on one forum I purchased new PCBs, made according to the originals but much more reliably. Also I had some other componets lying around like some 12X4, a large heap of 12AX7 (not my favourite tube scratch ) and some electrolytics.

    My idea is to make my PAS-3 operatiting and according to the original plans, though I got a hint from Tubes4HiFi how to make a minor adjustment to the phono stage. I don't mide swapping bad components to better ones and have a package sent from Tubes4HiFi (potentiometers and selector switch). However, when it comes to the input selector I have a problem, I would need a 6-pole/6-way switch and I haven't found any here in Sweden and the one ordered is a 2-pole. Either I have to do some major surgery to a number of 2-pole switches or I can find someone who has butchered some old instrument and salvaged a suitable switch.
    Still have some 4-5 amplifiers I really want to have in working order before I start working with this one. In the meantime here's the pics:

    Photos cannot be posted yet - forum rules.

    I will keep you posted about the progress and also will listen to suggestions and advices.

    Soundbrigade

    Posts : 10
    Join date : 2012-08-17
    Age : 63
    Location : Vänersborg, Sweden

    Re: A Swedish PAS-3 (and an intro)

    Post by Soundbrigade on Sun Mar 23, 2014 8:55 am

    I have ended up too many projects and too little inspiration  No . A mix of various small and not so small amps are piling up.

    Elsewhere I wrote this:
    I have a question about competitors.
    A loooooong while ago I bought the phono and line amp boards for a PAS3 that I had gotten (for free  Very Happy ). The original boards were in a terrible condition, with just some components mounted (or maybe most were desoldered).

    As I have invested in a new camera (Canon EOS M) and saw agood way to fill the financial hole this purchase has created - fixing my PAS-3 and sell it.
    However when I start to inspect the boards I bought I cannot really see that they correspond to the board layouts (from Tubes4HiFi) and slowly, slowly I realize I bought the boards from Vintage Electron (eBay) and now I start to wonder if the layout is similar to "Dynaco standard" (or Tube4HiFi standard)?

    Bare boards

    Stuffed boards

    I also hope and plan to keep the amplifier as close to the original as possible, though I read the notes from Tubes4HiFi, how to make adjustments here and there to get a better function.

    I recently got a message from someone who though he had som Dynaco stuff in the attic and wanted me to take care of it. let's see what that is. Have to wait until the guy's bad back has healed.

    Soundbrigade

    Posts : 10
    Join date : 2012-08-17
    Age : 63
    Location : Vänersborg, Sweden

    Re: A Swedish PAS-3 (and an intro)

    Post by Soundbrigade on Sun Mar 23, 2014 12:47 pm

    Didn't want to fiddle to much with a sticky thread so I try update my thread with a few photos showing the "guts" of my PAS3 in the state it was when I got it.







    Someone has made a serious attempt ( clown ) to enhance the amp. I have to quote Hamlet: The time is out of joint: O cursed spite,
    That ever I was born to set it right!
    I dn't despair that much, there's plenty, as I just wrote, of documention out there.

    On the photo is the power transformer missing, but I have gotten a new one, specially made for this amp.

    pmarcin

    Posts : 131
    Join date : 2009-01-20
    Age : 68

    Re: A Swedish PAS-3 (and an intro)

    Post by pmarcin on Sun Mar 23, 2014 9:29 pm

    Soundbrigade,

    Start with a new PSU from tubes4hifi or a new PS board from CVD reg board. CVD also sells clone boards for the PAS. I do recommend t4hifi's Aikido or TCLA or offerings from Dynaco Designs.

    Soundbrigade

    Posts : 10
    Join date : 2012-08-17
    Age : 63
    Location : Vänersborg, Sweden

    Re: A Swedish PAS-3 (and an intro)

    Post by Soundbrigade on Mon Mar 24, 2014 3:44 am

    Thanks for advice and links. I want to keep my PAS3 as close to the original as possible. However a (much) better PSU could be worth looking in to. I had an idea of using a small choke that I had dug up in my collections, together with the tube rectifier and big/small enough caps. Also I have been considering "lifting" the heaters a bit as that can enhance sound quality (avoiding diode effect between heater and cathode).

    pmarcin

    Posts : 131
    Join date : 2009-01-20
    Age : 68

    Re: A Swedish PAS-3 (and an intro)

    Post by pmarcin on Mon Mar 24, 2014 9:32 am

    CVD has two boards that are exact replacements.

    Soundbrigade

    Posts : 10
    Join date : 2012-08-17
    Age : 63
    Location : Vänersborg, Sweden

    Re: A Swedish PAS-3 (and an intro)

    Post by Soundbrigade on Sat Mar 29, 2014 3:51 am

    Complete amplifier dissembled. God, did I fight with the selector switch knob. Didn's see that there was a lockscrew keeping the knob in place. For a moment I thought it was glued in place by superglue.



    There're some scratches and dents on the front panel (I didn't do it!!!), bu I recall Tom Rapp' eonderful song The Jeweller.



    Will start to populate the boards I have, but this will take some time as there are three or four amps on my work bench right now. After some consideration, I am pretty tempted to try out some simple regulation for the PSU. The choke I have can be used elsewhere.

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