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


    Dyna PAS Spatial Contriol

    Share

    Mark Korda

    Posts : 33
    Join date : 2009-12-29

    Dyna PAS Spatial Contriol

    Post by Mark Korda on Thu Feb 01, 2018 1:08 pm

    Hi, I am playing around with preamps lately. I have a Dyna PAS 2 or 3 that has had it's tone controls taken out of the circuit by a friend a while back. He took out the scratch filter also.
    I keep looking at the stereo/mono spatial control and wonder if I could take that out too. It looks like the snipping of 5 wires would do it. 2 wires, red and green, left and right, come from the tape monitor. 2 other red and green wires come from the balance control. There is only one small jumper wire, black, from 1 pin on the spacial control to the balance control.( That wire also is connected with Mono A+B) on the spatial switch.
    Before I try anything do any of you have any ideas or instructions that might help? I wouldn't mind losing the tape monitor switch too but if it should stay thats fine.
    A big thank you has been already issued from me.
    I use a St-70 and a ST-35 for my amps. I keep playing around with passive preamps but others say active so my madness goes on. My goal is to strip the PAS of anything not needed in the circuit and I do have( phonograph) working to make this mod my friend did even better.
    I was also looking for a new more modern switch. I've seen one before but can't seem to locate the source anymore. I do have the gold jack set ready to install.....thanks so much for any info!....Mark Korda .
    avatar
    corndog71

    Posts : 673
    Join date : 2013-03-19
    Location : It can get windy here

    Re: Dyna PAS Spatial Contriol

    Post by corndog71 on Thu Feb 01, 2018 1:46 pm

    I was interested in the PAS preamps for a while.  After all of my research the facts that I kept running into was that they were mediocre preamps and easily bested in sound quality by more modern designs.  Or for the same money it would cost to put a modern circuit in a PAS box you can afford a better preamp like the SP13.  Which is what I ended up doing.

    I can see the appeal of the Dynaco PAS if you wanted to retain all of its features but if you're only going to gut the controls then why bother with that limited chassis design?  You can build an SP13 kit in a simple hammond box that would look better and definitely sound better.

    I totally get trying to make the most of what you got but in the long run I think you're wasting money by sticking with the PAS chassis.
    avatar
    PeterCapo

    Posts : 543
    Join date : 2008-12-05

    Re: Dyna PAS Spatial Contriol

    Post by PeterCapo on Thu Feb 01, 2018 2:14 pm

    Mark, if you have not already seen them, I highly recommend a series of recent studies of the original PAS by Audio Regenesis.  Look on the left side of the following web-page: http://www.audioregenesis.com/  They're the very best studies of the original PAS anywhere and are a must for anyone considering working on one.  The PAS is more complicated than working on, say, a Stereo 70. I've found that a properly refreshed PAS can be, IMO, a very sweet, satisfying preamp.

    Mark Korda

    Posts : 33
    Join date : 2009-12-29

    Re: Dyna PAS Spatial Contriol

    Post by Mark Korda on Thu Feb 01, 2018 2:56 pm

    Hi Corndog,
    this PAS is special. I had 2 back in 1988. I made these home-made faceplates and gave one PAS to a friend I met thru Audiomart. In return he modded mine to the Last PAS specs. He also wired my ST-70 into an Audio Purist 70 which uses 12AX7's instead of the 7199 tube. He is the buddy of the Purist Audio guy Jim Aud. They were in the Airforce together and I still talk to them.
    I keep doing sound tests with a nice passive preamp I built, a transformer project based passive preamp, and a Ace Zero Distortion preamp that looks like it was wired by a brain surgeon, rare black faceplate?, and the PAS and it's always a tie. My mission is make the PAS more bare-boned and use top parts. I see large Wonder caps as I write.
    Peter,
    I built a ST-35 a few years ago. It's my pride and joy, my flag ship amp. When I very carefully finished the wiring and plugged it in Pat Boone could be heard singing April Love with no source plugged in. It took a ride to VanAlstines to find out I had not grounded the new gold jacks. Been working puff ever since. Thanks so much for that site! I thought Google showed them all but I've never seen this one. I'm saving it for later tonight to look closer...vintage Hi-fi porn.
    Thanks so much you guys but I still wan't to snip out that spatial control.....Mark Korda
    avatar
    corndog71

    Posts : 673
    Join date : 2013-03-19
    Location : It can get windy here

    Re: Dyna PAS Spatial Contriol

    Post by corndog71 on Thu Feb 01, 2018 5:00 pm

    I recommend Clarity Cap CMR series for preamp caps.  I get them from http://www.hificollective.co.uk
    avatar
    tubes4hifi
    Admin

    Posts : 1478
    Join date : 2008-11-30

    Re: Dyna PAS Spatial Contriol

    Post by tubes4hifi on Wed Feb 07, 2018 7:50 pm

    I'm a little biased (well hey, I like tubes) but I'm siding with Cornwall here.  Even the "Last PAS" is an 80s upgrade, not anywhere near as good as the PAS mods I sold ten years ago.
    I posted several articles on this forum about why you should get an SP9 or SP12 for the same amount of money you could spend upgrading a PAS.  
    If you think a PAS sounds good, well, I just guess you've never really heard a good preamp, very sorry to say.
    Even the Transcedence preamp for $500 will blow the PAS away.  But IMHO the Transcedence sounds twice as good with a tubed power supply, they cut that corner.
    When the AIKIDO circuits came out a dozen years ago, sounded really good, but I added my tubed power supply and made a really good preamp a super great preamp.
    Welcome to the SP12, which then grew up with lots of finessed upgrades and better tubes and a dual mono power supply, and well . . . . you can read the reviews on this forum,
    or better yet on almost any audio forum on the internet.   Read AudioBill's latest post about the SP14 he FINALLY bought after wasting 3 years not having one.
    Deepee and Doc Brent have bought just about every preamp I've ever offered, and they are both now firmly in the SP14 camp.   Everyone else is missing out on great audio.


    Last edited by tubes4hifi on Wed Feb 07, 2018 9:10 pm; edited 1 time in total

    audiobill

    Posts : 357
    Join date : 2014-03-13
    Location : Philadelphia

    Re: Dyna PAS Spatial Contriol

    Post by audiobill on Wed Feb 07, 2018 8:37 pm

    Very Happy
    avatar
    erhard-audio

    Posts : 39
    Join date : 2017-04-07
    Age : 60
    Location : Tucson, AZ

    Re: Dyna PAS Spatial Contriol

    Post by erhard-audio on Wed Feb 07, 2018 9:04 pm

    on the subject of PAS upgrades, I guess I am biased.
    I took over Roy's PAS upgrade business some years back and have been steadily making improvements to the original 'OK' upgrade circuits which have now really come of age.
    Is it worth upgrading an old PAS?, well no doubt, there are many opinions about that, a lot of people seem to think they are, going by the success of the PAS upgrade kits business.  Smile
    Does one have to spend $1000?, absolutely not. Is it a waste of one's money to upgrade an old PAS, absolutely not.
    Not everyone wants to buy a new preamp, be it in a kit form or ready built.
    There is room in this market for both, depending on what a person wants and can afford.
    The Tubes4HiFi preamps are excellent units and fit very well into that market segment.
    And so do the PAS upgrades, they are a perfect fit for a certain market segment, are an excellent product and sell extremely well.

    audiobill

    Posts : 357
    Join date : 2014-03-13
    Location : Philadelphia

    Re: Dyna PAS Spatial Contriol

    Post by audiobill on Thu Feb 08, 2018 10:43 am

    To support Holger, I have a customer for whom his pas3x is of great sentimental "vintage" value, and merely wants the circuits brought up to date.

    Sponsored content

    Re: Dyna PAS Spatial Contriol

    Post by Sponsored content


      Current date/time is Thu Oct 18, 2018 3:21 pm