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


    PAS4 Preamp

    Share

    StereoGaryo

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

    PAS4 Preamp

    Post by StereoGaryo on Sat Nov 06, 2010 6:47 pm

    Hi gang.
    My first post here.
    I own one.
    Any comments?

    Bob Latino
    Admin

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

    Re: PAS4 Preamp

    Post by Bob Latino on Sat Nov 06, 2010 7:21 pm



    The PAS-4 is a nice preamp and much better sounding than the earlier PAS-2 and PAS-3 preamps. These were made in the early '90's and, as I understand it, not that many were made. The PAS-4 was only available as a wired preamp. It was never a "kit" preamp. I had the opportunity to work on one from a local customer and ran it against a STOCK PAS-3. The PAS-4 had noticeably better sound.

    That said, Roy at tubes4hifi has upgrade kits for the PAS-2, PAS-3 that will really make these earlier PAS preamps come alive. Link below ...

    Tubes4hifi PAS preamp mods

    If anyone is interested, the owners manual for the PAS-4 is at the link below ...

    PAS-4 owners manual (pdf)

    Bob


    Last edited by Bob Latino on Tue Mar 22, 2016 10:10 am; edited 1 time in total

    dynacophil

    Posts : 33
    Join date : 2010-10-26
    Age : 59
    Location : Berlin/Germany

    Re: PAS4 Preamp

    Post by dynacophil on Sun Nov 07, 2010 5:46 pm

    StereoGaryo wrote:Hi gang.
    My first post here.
    I own one.
    Any comments?

    me too, since 8 yrs now! And still glad about that purchase. Only deficite: those silly "shiny" applications on the knobs coming off...

    muncybob

    Posts : 14
    Join date : 2015-04-21

    Re: PAS4 Preamp

    Post by muncybob on Tue Apr 21, 2015 9:07 am

    I just joined the forum. Currently running a PAS-4 on loan to me and comparing it to a Conrad Johnson PV2. Have not run phono yet(waiting for my stylus to arrive) but cd's sound great compared to my old Rotel preamp. I am quit surprised that for less than 1/2 the cost of the CJ, the PAS-4 compared very favorably. It has a mixture of tubes in it and needs some cosmetic attention.
    I'm seriously considering buy this preamp, I believe the seller wants around $300...is that a fair price? I hesitate only because I'm not sure how much $$ I'll be at with new tubes and possibly having caps replaced due to age?

    GlacierJohn

    Posts : 38
    Join date : 2014-04-17

    Re: PAS4 Preamp

    Post by GlacierJohn on Tue Apr 21, 2015 3:31 pm

    muncybob wrote:I just joined the forum. Currently running a PAS-4 on loan to me and comparing it to a Conrad Johnson PV2. Have not run phono yet(waiting for my stylus to arrive) but cd's sound great compared to my old Rotel preamp. I am quit surprised that for less than 1/2 the cost of the CJ, the PAS-4 compared very favorably. It has a mixture of tubes in it and needs some cosmetic attention.
    I'm seriously considering buy this preamp, I believe the seller wants around $300...is that a fair price? I hesitate only because I'm not sure how much $$ I'll be at with new tubes and possibly having caps replaced due to age?

    The two preamps I switch in and out of my system are a newly restored CJ PV-2 and a Van Alstine Super Pas 3 I built in the early 90s. I don't know how close if at all the Super Pas III is to your PAS-4, but I like both the CJ and Super PAS III equally, they are just different flavors. That's why I switch them back and forth on whim. Whenever I do a switch I always like the new one better, just a change of pace I guess.

    tubes4hifi
    Admin

    Posts : 1261
    Join date : 2008-11-30

    Re: PAS4 Preamp

    Post by tubes4hifi on Tue Apr 21, 2015 3:56 pm

    from my own experience, neither the VanAlstine PAS3 or the CJ PV2 is as good as the Dynaco PAS4,
    it would compare closer with a CJ PV5 or PV6

    pmarcin

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

    Re: PAS4 Preamp

    Post by pmarcin on Wed Apr 22, 2015 8:24 am

    I owned the PAS-4 for three years. The line stage was pretty good, but I didn't listen to the phono section until I sold it. It was sensational. I wouldn't have sold it! I have since owned a Monarchy M-24. a chinese 6h30, a PAS-3 t4hifi upgrade and an Aikido 6922/6ca7, any one of which has a slightly softer sound.

    $300? Jump on it. The chrome on my knobs was pretty thin.

    muncybob

    Posts : 14
    Join date : 2015-04-21

    Re: PAS4 Preamp

    Post by muncybob on Wed Apr 22, 2015 1:36 pm

    Well, my stylus arrived today so I will soon have a chance to check out the phono stage. Tonight will be the 1st chance my wife will have to listen to the amps. Sometimes she has a better ear than I do, so it will be interesting to see if she hears anything differently. I also have a chance to score a Parasound 2100 for $400 or less. The remote, 12v trigger and usb options of the 2100 are very tempting, won't have a chance to audition that until next week. The PAS-4 asking price is $400(not the $300), if I decide to go with it I'll try to talk him down a bit as the cover needs a lot of work(some kind of stuff was glued onto it so it needs to be cleaned off, sanded, primed/painted) and it will need a power cord.

    Decisions, decisions!

    muncybob

    Posts : 14
    Join date : 2015-04-21

    Re: PAS4 Preamp

    Post by muncybob on Thu Apr 23, 2015 9:06 am

    Forgot to mention, the Dynaco currently has the following tubes, one unmarked and one marked 82219(line?) and in phono Tungsol 12107, Sylvania 34167, 82219 & 6DJ8(?)...I am lost as to why so many different tubes but I'm a complete newbie to tubes. Are there preferred tubes for the PAS-4?

    The Mrs said it was a fine line between the PAS-4 and the PV2 with slightly favoring the PV2 on cd's, plan to play the tt soon. BTW, what does PAS stand for?

    pmarcin

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

    Re: PAS4 Preamp

    Post by pmarcin on Thu Apr 23, 2015 11:02 am

    muncybob wrote: Are there preferred tubes for the PAS-4?
    Yes. Amperex and Siemens gold pin -- very expensive $55 -$200 ea.All 6922s have shot thru the roof. Go with Russian or NOS.

    -Paul-

    GlacierJohn

    Posts : 38
    Join date : 2014-04-17

    Re: PAS4 Preamp

    Post by GlacierJohn on Thu Apr 23, 2015 2:42 pm

    muncybob wrote:Forgot to mention, the Dynaco currently has the following tubes, one unmarked and one marked 82219(line?) and in phono Tungsol 12107, Sylvania 34167, 82219 & 6DJ8(?)...I am lost as to why so many different tubes but I'm a complete newbie to tubes. Are there preferred tubes for the PAS-4?

    The Mrs said it was a fine line between the PAS-4 and the PV2 with slightly favoring the PV2 on cd's, plan to play the tt soon. BTW, what does PAS stand for?

    Well that makes me feel a little better about my CJ PV2a, but after reading about the, new to me, PAS 4, I still want one.

    pmarcin

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

    Re: PAS4 Preamp

    Post by pmarcin on Thu Apr 23, 2015 4:13 pm

    Also, Panor hired some famous designer like John Curl to design it. He made the phono section really shine.

    muncybob

    Posts : 14
    Join date : 2015-04-21

    Re: PAS4 Preamp

    Post by muncybob on Mon May 11, 2015 11:02 am

    Well, I now own my first piece of tube gear. Was able to negotiate a slightly lower price on the PAS-4 and will put it on the bench for some needed tlc(cosmetic) soon. The phono section really shines on this pre, totally blew away the CJ and my current Rotel. It was a tough choice between the Dynaco and a Vincent pre (w/o phono) I had on loan but the phono section sealed the deal for me. Next adventure will be cleaning up my neglected vinyl collection. If only the Dynaco had a remote!

    muncybob

    Posts : 14
    Join date : 2015-04-21

    Re: PAS4 Preamp

    Post by muncybob on Wed May 13, 2015 8:33 am

    Can the 2nd output be used to run a powered sub?

    peterh

    Posts : 643
    Join date : 2012-12-25
    Location : gothenburg, sweden

    Re: PAS4 Preamp

    Post by peterh on Wed May 13, 2015 11:21 am

    muncybob wrote:Can the 2nd output be used to run a powered sub?
    Yes, they are interconnected internally.
    The manual says :
    "Two pairs of outputs are provided for your power amplifier(s). The two left channel RCA jacks are connected directly together inside of the PAS-4, as is the right channel pair."

    Confirmed by a loog at the schematics.

    But as you have so much trouble i will happily compensate your costs and take ownership of the pas4 :-)



    muncybob

    Posts : 14
    Join date : 2015-04-21

    Re: PAS4 Preamp

    Post by muncybob on Wed May 13, 2015 10:05 pm

    I'm enjoying "my trouble" peter, thanks anyways Smile

    Are there aluminum or metal knobs available for this? I removed the plastic ones and they cleaned up OK, but metal ones would be nicer. I am surprised for as good as this amp sounds there is not more discussion regarding the PAS4.

    Bob Latino
    Admin

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

    Re: PAS4 Preamp

    Post by Bob Latino on Thu May 14, 2015 8:27 am

    muncybob wrote:I am surprised for as good as this amp sounds there is not more discussion regarding the PAS4.

    The reason for this is that not too many of the PAS4's were made. Literally hundreds of thousands of PAS-2 and PAS-3 preamps were sold in the 1960's to go along with the ST-70 and the other Dynaco amps. The PAS4 dates from the 1990's after Panor bought the Dynaco brand name and tried to restart selling Dynaco tube gear. Not too many PAS4's were sold ... Probably only a few thousand units were ever produced and they are relatively rare. Every now and then I do see one for sale on Ebay. If in good working and cosmetic condition, they usually sell for $500+ Below is a link to a January, 2009 post our forum here on PAS4 modifications ...

    PAS4 modification link ..

    Bob

    muncybob

    Posts : 14
    Join date : 2015-04-21

    Re: PAS4 Preamp

    Post by muncybob on Thu May 14, 2015 10:29 am

    Curious to know what the original retail price was?

    peterh

    Posts : 643
    Join date : 2012-12-25
    Location : gothenburg, sweden

    Re: PAS4 Preamp

    Post by peterh on Thu May 14, 2015 11:33 am

    muncybob wrote:Curious to know what the original retail price was?
    Could we have a PAS-4 kit from tubes4hifi?
    I find the idea with a loop to a separate tonecontrol box interesting.


    pmarcin

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

    Re: PAS4 Preamp

    Post by pmarcin on Sat May 16, 2015 8:37 am

    muncybob wrote:Curious to know what the original retail price was?
    It was appx $825 and sold by  a NYC discounter. I bought mine for $525 new from a wholesaler, who was stuck with the stock, when they didn't sell. Mine had chromed knobs. There was also an an all chrome version. I sold mine for $375, because I only listened to the linestage, which, as [i]tubes4hifi[/i, states, was moderately good. The phono stage was superior and included a scratch filter. My bad.

    muncybob

    Posts : 14
    Join date : 2015-04-21

    Re: PAS4 Preamp

    Post by muncybob on Mon May 18, 2015 8:19 am

    Thanks for the info Bob. I am confused and if I knew how to read a schematic I guess I could answer my own questions...I have read talk of 2 tubes in the phono stage and elsewhere talk of 4 tubes. Which tubes are phono and which are line stage? Although the amp was checked by a tech and he said there is no problem with the caps I suspect that due to age it would be a good idea to start replacing them? You mention a good starting point would be the 2 line stage caps...exactly which ones are these?

    Also read talk of putting some PQ 7308's into the line stage and RCA 5751's in the phono. What would be the general consensus of replacement tubes without breaking the bank?

    I just finished giving the metal case a new paint job and cleaned up the face plate nicely. Now have some metal knobs on order to make her look like new.

    peterh

    Posts : 643
    Join date : 2012-12-25
    Location : gothenburg, sweden

    Re: PAS4 Preamp

    Post by peterh on Mon May 18, 2015 8:43 am

    muncybob wrote:Thanks for the info Bob. I am confused and if I knew how to read a schematic I guess I could answer my own questions...I have read talk of 2 tubes in the phono stage and elsewhere talk of 4 tubes. Which tubes are phono and which are line stage? Although the amp was checked by a tech and he said there is no problem with the caps I suspect that due to age it would be a good idea to start replacing them? You mention a good starting point would be the 2 line stage caps...exactly which ones are these?

    Also read talk of putting some PQ 7308's into the line stage and RCA 5751's in the phono. What would be the general consensus of replacement tubes without breaking the bank?

    I just finished giving the metal case a new paint job and cleaned up the face plate nicely. Now have some metal knobs on order to make her look like new.

    Wrong tubes would only break the board.  Don't mess with it unless it's broken!

    The only tubes that fit ( except riaa which is 12ax7 ) are ECC88 and it's equivalents.
    Whatever changes you do will certainly reduce it's value, this includes swapping components.


    Last edited by peterh on Mon May 18, 2015 10:55 am; edited 1 time in total (Reason for editing : Spelling and add 12ax7 exception)

    Pillo69

    Posts : 104
    Join date : 2012-04-11
    Location : Granada (España)

    Re: PAS4 Preamp

    Post by Pillo69 on Mon May 18, 2015 7:30 pm

    PAS4 use 12AX7 and ECC88 for Phono preamp. And one ECC88 for line amplifier. For each channel.
    Phono preamp gives that impression.
    Not if it would go well with VTA card with tone controls.

    StephenMH

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

    Re: PAS4 Preamp

    Post by StephenMH on Tue May 19, 2015 12:05 pm

    Hello All!

    WoW! What a Face  I did not know what I have! I Bought a PAT-4 that was already upgraded to FET THREE BY Frank Van Alstine from E-Bay in the Late nineties for around three hundred dollars. I just finish opening it up what a Anti-Climax no tubes Sad  and I'm a Tube Lover. It brings back memories; when I open up not too long after I Bought it. But the inside still looks nice like not too long rebuild. Since I got it Open will take some Pictures. & need to take some pictures of Two of Dynaco ST70 any how. Who knows the PAT-4, I mean the FET THREE might need a UpGrade any how. I need to  connect my Turntable(Music Hall MMF-5) to it anyway; to check out the Sound Quality  also to see if it still works.

    Take Care and Enjoy the Best of a Healthy Soulful Prosperous Life!  farao
    Peace, Love and Soulful Oneness! Stephen

    GP49

    Posts : 718
    Join date : 2009-04-30
    Location : East of the sun and west of the moon

    Re: PAS4 Preamp

    Post by GP49 on Tue May 19, 2015 12:29 pm

    StephenMH wrote:Hello All!

    WoW! What a Face  I did not know what I have! I Bought a PAT-4 that was already upgraded to FET THREE BY Frank Van Alstine from E-Bay in the Late nineties for around three hundred dollars. I just finish opening it up what a Anti-Climax no tubes Sad  and I'm a Tube Lover.

    PAT-4 never had tubes, only bipolar transistors (PAT = Pre Amp Transistor, PAS = Pre Amp Stereo...when the PAS was introduced in 1958 there were no transistors in hi-fi gear).

    PAT-5 didn't have tubes either...bipolar transistors and an operational amplifier IC.  PAT-5 Bi-FET replaced the conventional op amp with one having an FET input.

    Both PAT-4 and PAT-5 were by the original, traditional Dynaco company in the Philadelphia area.  PAS-4 was by Pan Orient, the company that bought the trademarks of Dynaco from Tyco. It is not clear whether they bought the patents and the rights to intellectual property such as circuit designs. Nobody from the original Dynaco company was involved with Pan Orient.

    Sponsored content

    Re: PAS4 Preamp

    Post by Sponsored content Today at 7:47 pm


      Current date/time is Thu Sep 29, 2016 7:47 pm