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    PAS4 Preamp

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    StephenMH

    Posts : 10
    Join date : 2014-08-30
    Age : 61
    Location : Aurora, Co.

    Dynaco PAT-4

    Post by StephenMH on Tue May 19, 2015 1:41 pm

    Yes You're Right! My Memory is coming back! In the Back of my Mind, I want it be tubes(Maybe in the Front of My Mind)Lol...  Laughing  There seems not to many Upgrades for the PAS-4, Do You or anyone Else  Know of any Mod or Upgrade with tubes for the PAS-4 and If so What's the Best Place or Website for the Best Value for Quality Sound? or is it worth it?

    Thanks for the Info!
    Stephen

    StephenMH

    Posts : 10
    Join date : 2014-08-30
    Age : 61
    Location : Aurora, Co.

    Re: PAS4 Preamp

    Post by StephenMH on Wed May 20, 2015 10:52 am

    Thank You! I will check it out.  bounce  cheers   I've been doing some Research and most of the Website are for mostly PAS-2&3 or PS-5&6. Plus I'm new at building , Mod and upgrading. Also do not know how to read Schematic yet. I've only Build, Rebuild and upgrade my own computers since the middle nineties(One of my Hobbies).
    Again Thank You for your time and Patients! Stephen

    tubes4hifi
    Admin

    Posts : 1261
    Join date : 2008-11-30

    Re: PAS4 Preamp

    Post by tubes4hifi on Thu Jun 25, 2015 2:07 pm

    it's been awhile since I looked at this thread, so replying to some of the OLDER questions . . .
    no joke - PAS stands for Pre Amp Stereo; PAM (as in the old PAM-1) stands for Pre Amp Mono

    Several years ago I tried to sell a clone of the PAS-4, I had a few PCBs made, never ever sold one.
    If I had to do it again, I would redesign the power supply section using modern devices, but keep the rest of it the same.

    But a guesstimate of price would be north of $1000 for a kit, since a new PAS3 kit runs about $700-800.
    The PAS-4 has a lot more controls and switches, and much better circuit design, also needs a lot more power to run it.
    I think my SP12+PH12 will beat it on performance for about the same cost.

    StephenMH

    Posts : 10
    Join date : 2014-08-30
    Age : 61
    Location : Aurora, Co.

    Been Looking at the SP9 and the SP12!

    Post by StephenMH on Fri Jun 26, 2015 7:05 pm

    tubes4hifi wrote:it's been awhile since I looked at this thread, so replying to some of the OLDER questions . . .
    no joke - PAS stands for Pre Amp Stereo;   PAM (as in the old PAM-1) stands for Pre Amp Mono

    Several years ago I tried to sell a clone of the PAS-4, I had a few PCBs made, never ever sold one.
    If I had to do it again, I would redesign the power supply section using modern devices, but keep the rest of it the same.

    But a guesstimate of price would be north of  $1000 for a kit, since a new PAS3 kit runs about $700-800.
    The PAS-4 has a lot more controls and switches, and much better circuit design, also needs a lot more power to run it.
    I think my SP12+PH12 will beat it on performance for about the same cost.




    I've been Looking at the SP9 and The SP12. I was going more toward the SP9 Because of the Tone Controls and the Price.
    Is the SP12 a very large difference price value? Tone control is very important to me for the old music I have including Albums
    from the Seventies some recorded well and some not. I'm building my music collection on my computer also connecting to my Audio
    Systems.

    Also I'm hearing and reading its a good combination for Tube Preamp and Solid State Amp(I have both Tube and Solid state Amp that I switch around. But I never experienced a tube preamp in my system. I'm using a McIntosh C39 Preamp at this moment.

    Thanks Anyone for any comment; reaching for Audio Nirvana! Laughing  cheers
    Stephen

    StereoGaryo

    Posts : 13
    Join date : 2010-11-06
    Location : SoCal

    Re: PAS4 Preamp

    Post by StereoGaryo on Mon Mar 21, 2016 3:21 pm

    Just a few quick comments since my original post...
    As I recall, the original retail for the PAS4 was $1000.00 in black and $1100.00 for chrome. I was a dealer in Southern California for Panor in the '90's
    John Nunes designed the PAS4 and put a lot of effort in making the phono stage the star of this preamp. It really shows. He also had an association with MFA back in the day.
    I love mine and use it daily.

    pmarcin

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

    Re: PAS4 Preamp

    Post by pmarcin on Tue Mar 22, 2016 9:59 am

    John,
    You are spot on about the phono stage. I sold mine without ever listening to the phono stage (350 USD.) It sold in one day and had chrome knobs. I decided to audition the phono stage at long last. It was tremendous! I had my regrets to say the least.

    Bob Latino
    Admin

    Posts : 2378
    Join date : 2008-11-26
    Location : Massachusetts

    Re: PAS4 Preamp

    Post by Bob Latino on Tue Mar 22, 2016 10:16 am

    The PAS-4 was very well made. One large PC board with sealed solder traces ... These units still sell for big bucks if you can find one ... See photo below ..

    Bob



    pmarcin

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

    Re: PAS4 Preamp

    Post by pmarcin on Thu Mar 24, 2016 5:03 am

    I wasn't that impressed with the linestage. I had built your SP9 and found that unit at least as satisfying.

    peterh

    Posts : 642
    Join date : 2012-12-25
    Location : gothenburg, sweden

    Re: PAS4 Preamp

    Post by peterh on Tue Apr 12, 2016 1:31 pm

    tubes4hifi wrote:OK, I'm going to order 4 PCBs tomorrow, after I confirm orders.  I'll be building one myself of course.

    I'm in. What about description ( component placement, schematics ?)
    I guess i can source needed components in europe. And guess what, it's will
    be populated with JJ tubes :-)

    tubes4hifi
    Admin

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    Join date : 2008-11-30

    Re: PAS4 Preamp

    Post by tubes4hifi on Tue Apr 12, 2016 2:18 pm

    I'll be including all documentation, schematics, parts list, follow-up, etc

    tubes4hifi
    Admin

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    Join date : 2008-11-30

    Re: PAS4 Preamp

    Post by tubes4hifi on Wed Apr 20, 2016 8:08 pm

    OK guys, come and get them!!   PCBs and parts came in today, here's a photo of the board.
    PCBs shipping out tomorrow.  I've got one left for myself, and one more left for someone lucky who grabs it up quick!
    I should have the board stuffed with parts by Saturday (got to finish another customer preamp tomorrow) and likely
    powered up and tested by middle of next week, so check back here for more photos!



    The left half of the board is the phono stage and line stage, identical to the original, although I'm adding the provision to substitute
    6FQ7 or 12AU7 tubes in the line stage with minor resistor changes. The right half of the board includes two filament regulators,
    one for the phono section, one for the line stage, and SIX individual high voltage regulators, one for each tube (same scheme as the orginal,
    but using newer, better parts). The HV rectification is done using schottky diodes, each with an RC filter across it.
    And finally, in the bottom right, is the original auto mute circuit, using a timer IC and a relay to disconnect the outputs during warmup.
    Right down the middle are 6 large film capacitors for HV bypass (one for each tube), also same as original.


    Last edited by tubes4hifi on Thu Jun 02, 2016 9:03 pm; edited 1 time in total

    tubes4hifi
    Admin

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    Re: PAS4 Preamp

    Post by tubes4hifi on Sat Apr 23, 2016 3:10 pm

    OK, so here's the board stuffed with all parts, now just need to power it up and test, check back in a few days . . .


    Sal

    Posts : 223
    Join date : 2009-02-05
    Location : Central New Jersey Dynaco-ST70.com

    Re: PAS4 Preamp

    Post by Sal on Sat Apr 23, 2016 6:01 pm

    This PAS-4 and work bench looks familiar...  Very Happy

    I was lucky to find it in the original box and with the original tubes.

    Sal

    Bob Latino wrote:The PAS-4 was very well made. One large PC board with sealed solder traces ... These units still sell for big bucks if you can find one ... See photo below ..

    Bob



    Bob Latino
    Admin

    Posts : 2378
    Join date : 2008-11-26
    Location : Massachusetts

    Re: PAS4 Preamp

    Post by Bob Latino on Sat Apr 23, 2016 6:38 pm

    Sal wrote:This PAS-4 and work bench looks familiar...  Very Happy

    I was lucky to find it in the original box and with the original tubes.

    Sal

    Sal - your first post in about a year and a half ? Where have ya been? We missed ya ?

    Bob

    Sal

    Posts : 223
    Join date : 2009-02-05
    Location : Central New Jersey Dynaco-ST70.com

    Re: PAS4 Preamp

    Post by Sal on Sat Apr 23, 2016 10:45 pm

    Bob Latino wrote:
    Sal wrote:This PAS-4 and work bench looks familiar...  Very Happy

    I was lucky to find it in the original box and with the original tubes.

    Sal

    Sal - your first post in about a year and a half ? Where have ya been? We missed ya ?

    Bob

    Hi Bob,
    Sal's Capacitor Corner is sucking all my free time to the point I took down my Dynaco-ST70.com website. There are only so many hours in a day... I was getting burned out... I still have one ST-70 restoration/upgrade to finish for a customer. I was getting to many requests for Dynaco restorations and repairs.

    Sal

    tubes4hifi
    Admin

    Posts : 1261
    Join date : 2008-11-30

    Re: PAS4 Preamp

    Post by tubes4hifi on Sat May 21, 2016 5:37 pm

    check out the new Dynaco PAS-4 clone (yes, it's finally a reality!)

    daveshel

    Posts : 148
    Join date : 2011-11-06
    Location : Tucson AZ USA

    Re: PAS4 Preamp

    Post by daveshel on Sun Jun 19, 2016 9:35 pm

    What if this board could be mounted in a PAT5 chassis - all the switching and panel connections would already be in place. Looks to me there's not enough space in the 16" wide chassis to accommodate the PT. If we had a cube-shaped PT, maybe it could be hung off the outside of the back wall, like Van Alstine did with the Super PAS Three - but I don't see a way to squeeze in that toroidal, unless it's short enough to be mounted on a plane higher than the main board.

    tubes4hifi
    Admin

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    Join date : 2008-11-30

    Re: PAS4 Preamp

    Post by tubes4hifi on Sun Jun 19, 2016 9:54 pm

    great idea Dave, but the PAT5 is only 13.5 x 11.75", maybe the power transformer could fit vertically where the speaker outputs are

    daveshel

    Posts : 148
    Join date : 2011-11-06
    Location : Tucson AZ USA

    Re: PAS4 Preamp

    Post by daveshel on Sun Jun 19, 2016 10:15 pm

    tubes4hifi wrote:great idea Dave, but the PAT5 is only 13.5 x 11.75", maybe the power transformer could fit vertically where the speaker outputs are

    We don't need the speaker outputs. They're not a key feature. If we could fit a transformer, this could be a cool upgrade path.

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