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The Dynaco Tube Audio Forum

Dedicated to the restoration and preservation of all original Dynaco tube audio equipment - Customer support for Tubes4hifi VTA tube amp and preamp kits and all Dynakitparts.com products


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    VTA SP12 and PH12 Build Thread

    pmit2188
    pmit2188


    Posts : 7
    Join date : 2011-08-13
    Age : 65
    Location : Michigan,USA

    VTA SP12 and PH12 Build Thread - Page 6 Empty Re: VTA SP12 and PH12 Build Thread

    Post by pmit2188 Sun Aug 21, 2011 7:17 am

    Ed, It's been weeks and hundreds of us are waiting for you to finish this story. It has been a great thread to follow. A few may respond to your posts but hundreds just read with anticipation. Please let us know how your system sounds. Thanks.
    tubes4hifi
    tubes4hifi
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    Post by tubes4hifi Tue Aug 23, 2011 4:47 pm

    I've emailed Ed several times but I'm taking a wild guess that his personal life is tough right now.
    (job, family, who knows? it's the economy, stupid!)
    Meanwhile, I've sold several more SP12s, today I got an email from a customer in Russia who just finished his, and he is comparing it
    to his very high end Sony preamp (I researched it, a special limited edition from about 10 years ago that sold for $6000), here is his comment:
    "Sound, is very very good. I have a SONY TA-E1 preamp, sound of SP12 close to that league of preamps. Sound is very gentle, with little beautifull coloration, good dynamics and near perfect sound stage. One word - thank you Roy"
    KenH
    KenH


    Posts : 2
    Join date : 2011-08-18

    VTA SP12 and PH12 Build Thread - Page 6 Empty SP12 and PH12 build

    Post by KenH Tue Aug 30, 2011 7:05 pm

    Hello, my name is Ken and I am new to the forum. I am also in the process of finishing the build of a SP12 and PH12, between this build post and Roy I would like to thank you all for your help (don't know how Roy answers everyone all I can say is he provides the very best in customer service). It has been 40 years since I had looked at a schematic so the build thread has been quite helpful. I am inclosing a couple of photos hoping they might help others as well, based upon what I have read or seen in other post. Next step is to complete the connections and fire it up, hopefully without flames.


    http://www.flickr.com/photos/38185099@N05/6098069470/
    http://www.flickr.com/photos/38185099@N05/6098069940/

    VTA SP12 and PH12 Build Thread - Page 6 6098069470
    mantha3
    mantha3


    Posts : 302
    Join date : 2010-11-10

    VTA SP12 and PH12 Build Thread - Page 6 Empty Re: VTA SP12 and PH12 Build Thread

    Post by mantha3 Wed Aug 31, 2011 6:48 pm

    I remember Joshua didn't finish his build and had his pre listed in the for sale listings on this forum.. I wonder if Ed put this on the back burner too.

    I live in Minnesota.. I can see people putting this stuff off during the summer.. They will be back.
    avatar
    Guest
    Guest


    VTA SP12 and PH12 Build Thread - Page 6 Empty Re: VTA SP12 and PH12 Build Thread

    Post by Guest Wed Aug 31, 2011 10:05 pm

    KenH wrote:Hello, my name is Ken and I am new to the forum.

    That's a great avatar. It looks like the KISS principle was overlooked when wiring that baby! affraid
    jdmoninger
    jdmoninger


    Posts : 15
    Join date : 2011-02-13

    VTA SP12 and PH12 Build Thread - Page 6 Empty Re: VTA SP12 and PH12 Build Thread

    Post by jdmoninger Wed Oct 12, 2011 2:09 pm

    I'm still here! I have not touched the SP12/PH12 though. Too many other things going on. However, I think I will send this to Roy to have it completed.
    tubes4hifi
    tubes4hifi
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    VTA SP12 and PH12 Build Thread - Page 6 Empty progress ??

    Post by tubes4hifi Thu Oct 27, 2011 10:47 pm

    Ed, Pete, JD, Ken . . . . haven't heard from you guys lately, how's it going?
    jdmoninger
    jdmoninger


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    Join date : 2011-02-13

    VTA SP12 and PH12 Build Thread - Page 6 Empty Re: VTA SP12 and PH12 Build Thread

    Post by jdmoninger Thu Oct 27, 2011 11:19 pm

    Just need to reconnect some of the wires before I send it to you. I hope to do it Saturday but I have a final exam in Geriatrics next week.

    Thanks for checking in! Cheers,
    Joshua
    KenH
    KenH


    Posts : 2
    Join date : 2011-08-18

    VTA SP12 and PH12 Build Thread - Page 6 Empty Re: VTA SP12 and PH12 Build Thread

    Post by KenH Thu Jan 05, 2012 10:34 pm

    Hi Roy,

    Just finished build on the SP12 Very Happy So far everything sounds good still need to test phono section. Will post some photos soon. Thanks for all your help and the users who have contributed to this forum.
    Thanks,
    Ken
    jdmoninger
    jdmoninger


    Posts : 15
    Join date : 2011-02-13

    VTA SP12 and PH12 Build Thread - Page 6 Empty Re: VTA SP12 and PH12 Build Thread

    Post by jdmoninger Thu Jan 05, 2012 11:01 pm

    WEll, Ed fixed my Sp12/Ph12 and my goodness!!! This is the perfect preamp for my modern ST-70 build from Bob Latino and 1990s vintage AR303A speakers. There is nothing not to like except the room in which I've got this stuff set up in, but I can't fix that right now. All music types are a joy with this. There is warmth without coloration or bloating, clean and crisp highs with no brittleness, smooth and detailed mids...it's all wonderful from 20 to 20k, or about whatever my ears' range is. If you've been considering one of Ed's preamps, DO IT.
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    Newportcycle


    Posts : 19
    Join date : 2010-09-29
    Location : Central Maine

    VTA SP12 and PH12 Build Thread - Page 6 Empty Re: VTA SP12 and PH12 Build Thread

    Post by Newportcycle Fri Jan 06, 2012 6:45 am

    Josh, glad to hear your up and running. Can you share what issues needed to be rectified?
    jdmoninger
    jdmoninger


    Posts : 15
    Join date : 2011-02-13

    VTA SP12 and PH12 Build Thread - Page 6 Empty Re: VTA SP12 and PH12 Build Thread

    Post by jdmoninger Fri Jan 06, 2012 12:49 pm

    I can't share the issues very well. I sent the unit to Ed. He can tell more. I know there were some cold solder joints on the Aikido board but newer versions of the kit don't use the aikido board. It's very thick. Ed thinks the solder I was using was no good. I agree. When I built my ST70 there were no problems with solder joints and 5 years later it still works wonderfully with no problems. Anyway, Ed could have a better answer. The original symptoms can be read about earlier in this thread.
    mantha3
    mantha3


    Posts : 302
    Join date : 2010-11-10

    VTA SP12 and PH12 Build Thread - Page 6 Empty Re: VTA SP12 and PH12 Build Thread

    Post by mantha3 Fri Jan 06, 2012 2:20 pm

    I had good luck soldering PCB using a Wellman 45 Watt soldering pencil and then using a real thin higher price sliver content solder. the 45 watt iron gets hot pretty quick and holds temp well so the soldering joint gets hot quick and flows the solder well and deep in the joint.

    tubes4hifi
    tubes4hifi
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    Post by tubes4hifi Sat Jan 07, 2012 3:59 pm

    hey Josh, just to remind you and everyone else that my name is Roy, here at "tubes4hifi", and I repaired your SP12 here in November, Ed is your fellow forum member that bought the very first SP12 preamp, you bought the 2nd one.
    You and Ed and John (John didn't have any problems and did alot of his own "improvements") were the only ones using the original AIKIDO PCB, and both had problems, which is why I came out with the improved design that everyone else is now using. If I remember you may have used "lead-free" solder or "silver-solder" neither of which works as well as good ole reliable Kester 60/40 which is the same generic stuff Radio Shack sells, those don't always melt and flow well.
    Those can work with a hot iron, it's always better to run a hot iron and solder fast than a cool iron and solder slow, if you can't do a good joint in 2-3 seconds something is wrong.
    I've already deleted all our emails from 2-3 months ago, I probably sent you a web page link but I can't find that either, I've got a photo record on my other computer of the service.
    jdmoninger
    jdmoninger


    Posts : 15
    Join date : 2011-02-13

    VTA SP12 and PH12 Build Thread - Page 6 Empty Re: VTA SP12 and PH12 Build Thread

    Post by jdmoninger Sat Jan 07, 2012 7:58 pm

    So sorry Roy! I'm terrible with names as a general rule. That was a huge oversight on my part. Of course, in retrospect I know who is who.

    I was using Radio Shack Silver solder but I won't be using it ever again.
    edgobb
    edgobb


    Posts : 71
    Join date : 2010-11-09
    Location : Texas

    VTA SP12 and PH12 Build Thread - Page 6 Empty Long Awaited Update

    Post by edgobb Sun Sep 08, 2013 4:42 pm

    After about a billion years, I am finally getting around to updating this thread with my impressions.

    After a few hundred hours of listening, I love my SP-12. It has a clarity that I never had with the original PAS-2s that I own. I can hear the individual brush bristles on the snare head when I listen to Coltrane or Chet Baker. I hear the clear breaths taken by vocalists and the soundstage is as accurate as my current speakers will allow. Plugged into my VTA Upgraded ST-70, I am thrilled with my home listening experience.

    My biggest problem is that I'm an early adopter of technology and of those gadgets that I just "have to have." I get excited about something and then dump my soul (and $$$) into it. You should see the pile of "newest and bestest" phones and pdas that I have in my closet...some caught on and some bombed big time.

    I was the first to buy this circuit and kit from Roy and it used the original Aldiko board. Unbeknownst to us, the addition of the PH-12 phono stage caused problems with noise when it was added to the circuit. I got the thing meticulously put together, as you can see from my chronicles in this thread, but when it turned it on there was noise that I just couldn't get to the bottom of. Throughout this process,
    Roy was right along with me; suggesting and emailing and doing everything that he could to help me troubleshoot this thing. In short, Roy was just awesome as I built and troubleshot. It was great to get to know him a little bit and I really enjoyed our exchanges...I learned a lot and had a lot of fun throughout.

    I ultimately ended up sending it to Roy to have it fixed because my efforts just weren't producing any results. This sucker still hummed and I felt like a failure. Roy found that I had not handled my ground bus properly on the input/output section and made some modifications to the power supply board and the physical layout of the preamp as well as added a choke. I compensated Roy for his efforts, and he was more than generous in the level of service and amount of time and resources that he invested getting my preamp in top performing shape. I know that I paid Roy way less than he invested and for that I am grateful and ecstatic with the final product.

    My "must have this now" personality has earned me a one-of-a-kind incarnation of the SP-12 with PH-12 phono stage that performs better than I could have ever hoped. I highly recommend and implicitly trust Roy Mottram and any of the VTA products. And I am happy that this little Dynaco community exists. My music listening experience has been profoundly impacted by the efforts of Roy as well as Bob Latino, who sold me and helped me upgrade the VTA board in my ST-70.

    Stay tuned. I want to build a headphone amp, and I've just acquired a pair of Dynaco Mark IIIs. Oh, and I've found a set of Paul Carmody speakers that I want to build. Gonna have to sell some stuff soon. Mad 

    My biggest complaint at this point is that Roy went and designed the SP-14 pre and PH-16 phono...and I want them now.

    Cheers,
    Ed

    duder1982
    duder1982


    Posts : 6
    Join date : 2009-07-12

    VTA SP12 and PH12 Build Thread - Page 6 Empty Re: VTA SP12 and PH12 Build Thread

    Post by duder1982 Wed Jan 12, 2022 4:08 pm

    I know this is an old thread, but just wanted to share my situation. About 5 years ago I purchased a used assembled SP12 with remote from Roy. There was very slight hum that I couldn't track down. In his defense he had taken it in on trade, so who knows what wasn't assembled correctly. I removed the remote and input pc cards and wired directly to the inputs, replaced the selector switch with one of Tubes4hifi's basic selector switch, replaced the volume switch with a Alps Blue, and added the PH6 phono pre amp board. Needles to say, besides the Phono input, this pre is dead silent. I currently have it hooked up to my freshly built Nelson Pass Amp Camp Amp and Klipsch Heresys. Now as for the phono input, this card was paired once with the PC5 board and as a stand alone phono pre amp. Neither of those 2 had any hum, so I have to believe that either its the tubes, the way the wiring is ran, or the 12 vdc just isn't enough. Any thoughts?
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    psvoboda


    Posts : 1
    Join date : 2022-04-10

    VTA SP12 and PH12 Build Thread - Page 6 Empty Re: VTA SP12 and PH12 Build Thread

    Post by psvoboda Mon Jun 06, 2022 2:26 am

    jjones3318 wrote:Apologies - it was post 74, not 73:

    jjones3318 wrote:
    I eventually figured out that my hum was not 60Hz; it was 120Hz, which I read was probably power supply ripple.  I strongly suggest you search the net for an online signal generator or sound files you can download of 60Hz and 120Hz sine waves to compare to the hum from your preamp - it's very helpful to know what frequency the hum is.

    From there the game was improving PSU filtering so I put a choke in the place of R17 (Hammond 155J) which eliminated the hum from the SP12, and significantly reduced it from the PH12.  To get rid of the rest of the hum from the PH12 I put another choke (Hammond 156G) in series from where I took the B+ from the center of the AIKIDO board, followed by paralleled (2) .33uF Nichicon caps.  That did the trick.


    One of my hum/noise issues was due to some cold solder joints on the board.  The other I isolated to being 120Hz, which was ripple on the B+.  After adding the extra filtering noted above, I can't hear any noise at all from the AIKIDO, and only a little from the PH12 when I get to step 22 of 24 on the attenuator - this is with no input.

    I'm very pleased with the SP12/PH12.


    Regards,
    JP  


    Hi. I would like to add the choke to my buzzing SP12 as I know my power is dirty. However I am not sure where is R17 in the diagram. I have TRIAD C-3x choke. Is this totally inappropriate?
    tubes4hifi
    tubes4hifi
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    VTA SP12 and PH12 Build Thread - Page 6 Empty Re: VTA SP12 and PH12 Build Thread

    Post by tubes4hifi Mon Jun 06, 2022 2:54 pm

    to duder1982
    the original SP12 did not have a large enough transfomer to power anything other than the SP12 board,
    adding a phono board would require adding another filament transformer and filament power supply.
    tubes4hifi
    tubes4hifi
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    Post by tubes4hifi Mon Jun 06, 2022 3:04 pm

    to psvoboda
    there is no R17 in an SP12, unless maybe you have one of the original two which were actually original Glass-Ware AIKIDO boards, I haven't looked at any of that documentation in over 14 years.
    Those didn't have a tube rectifier. The choke would go after the first cap in the power supply, before a 2nd cap. On a real SP12, after C11 and before U1.

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