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    Anybody have experience with Curcio Audio?

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    muncybob

    Posts : 14
    Join date : 2015-04-21

    Anybody have experience with Curcio Audio?

    Post by muncybob on Thu Oct 01, 2015 9:39 am

    I am looking for somebody to do some work on my PAS4. I receieved an email from my inquiry to Curcio Audio and his reply seemed to be very knowedgable.

    stewdan

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    Age : 78
    Location : Houston Texas

    Re: Anybody have experience with Curcio Audio?

    Post by stewdan on Thu Oct 01, 2015 5:37 pm

    Hi --- Well, he is the Dynaco Doctor according to the web and his website.  There are lots of articles on his website dealing with rebuilding the original tubed Dynaco Units.  I don't remember seeing anything there on the PAS4 though.  

    He published several articles in the Audio Amateur Magazine back in the 1980s (at least I think it was the 80s).

    Many years back, I bought some of his blank PCBs for the Dynaco Mark III 60w Amplifier. The empty boards were affordable. But, I felt that his populated boards were too expensive and if he installed them, they were extremely expensive. IMHO

    There is no way around it, good tech support is expensive.

    Hope that I have helped.

    muncybob

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    Join date : 2015-04-21

    Re: Anybody have experience with Curcio Audio?

    Post by muncybob on Fri Oct 02, 2015 7:16 am

    Thanks for the info! He made several suggestions in his email back to me and I'm guessing my lack of experience with electronics is gonna cost me for sure. He wants $100 to fully check the unit before he makes any suggested changes.

    PeterCapo

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    Join date : 2008-12-05

    Re: Anybody have experience with Curcio Audio?

    Post by PeterCapo on Fri Oct 02, 2015 8:59 am

    Will he apply the $100 toward any changes he suggests?  If so, it's not so bad.

    muncybob

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    Join date : 2015-04-21

    Re: Anybody have experience with Curcio Audio?

    Post by muncybob on Fri Oct 02, 2015 10:09 am

    PeterCapo wrote:Will he apply the $100 toward any changes he suggests?  If so, it's not so bad.

    I don't think so.....here is his reply from my original inquiry:

    The PAS4 is a solid preamp with several opportunities for significant improvement.

    The first step would be to perform an initial analysis to make sure that the basic preamp has no issues in it's power supply and look for potential problems with leaky or weak capacitors, power resistors, tubes, connectors, switches and pots. Before any work begins, it is essential that the foundation of the preamp is sound (to prevent any future reliability problems)

    To begin the upgrades, I would first change the operating parameters in the line stage to provide much better linearity. This will manifest itself a improved dynamics and an overall more open sound.

    If you are using your phono stage, I would change the operating parameters of that stage as well plus correcting the RIAA filter.

    The final step would involve adding servo voltage regulation to all stages of both the phono and line amplifier stages. This will be the most dramatic improvement with much improved bass and mid-range definition and articulation gains.

    The cost will depend on the condition of the preamp (as identified in our first step) and which if the three options you elected to choose. They are interdependent such that the price depends on which of the three are chosen.

    Our standard policy would be to have you send your preamp to us and for a flat fee of $100, we perform the initial analysis and present a report to you along with the pricing for any remediation repairs. At that time, I can provide you with a price for any combination of the three options you choose.

    PeterCapo

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    Re: Anybody have experience with Curcio Audio?

    Post by PeterCapo on Fri Oct 02, 2015 10:30 am

    muncybob wrote:
    PeterCapo wrote:Will he apply the $100 toward any changes he suggests?  If so, it's not so bad.

    I don't think so.....

    I see what you mean.  Well, I suppose you still might specifically ask him if he'd be willing to apply the $100 towards the work and see what he says.

    Thing is, reading through his description, he is talking about making significant changes that I suspect could be fairly expensive.  If you value the preamp at all for its originality, and if it is a good preamp to begin with, then simply refreshing it with one-to-one parts replacement might be the way to go and less expensive.  You might ask Sal Brisindi, who builds the new dynakitparts products, as well as, IIRC, Bob's amps: http://www.dynaco-st70.com/

    peterh

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    Re: Anybody have experience with Curcio Audio?

    Post by peterh on Fri Oct 02, 2015 10:51 am

    muncybob wrote:I am looking for somebody to do some work on my PAS4. I receieved an email from my inquiry to Curcio Audio and his reply seemed to be very knowedgable.

    The dynaco pas4 is outdated and an environmental hazard. Send it to me and i will
    take care of it in an environmental friendly manner.

    As a special initiative to save precious metals we pay a bonus of 200 dollars to pay for
    shipping and destruction.


    pmarcin

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    Age : 69

    Re: Anybody have experience with Curcio Audio?

    Post by pmarcin on Fri Oct 02, 2015 2:19 pm

    I actually had a PAS-4. The linestage is good and  the phono is spot on. I don't see how he
    could add voltage regulation to each stage since each is on a single circuit board.

    I think he confuses the PAS4 with the PAT4. I did. 'Update my Dynaco' has the PAT4 updates.

    Mr. Curcio sounds like he's selling  you a bill of goods.Per chance are you interested in Florida reall estate? Sam Kim had some interesting things too say about Mr, Curcio's 'designs. The PAS4 was largely designed by John Nunes.


    Goldpt wrote:The task of updating the circuitry for the vacuum tube Stereo 80, Stereo 160, and PAS-4 was accomplished by John Nunes in San Jose, California. The PC board designs were done by Arn Roatcap in Sunnyvale, California. The factory assembly of these three products was done for Dynaco by TIBI Electronics in Los Angeles.

    pmarcin

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    Re: Anybody have experience with Curcio Audio?

    Post by pmarcin on Fri Oct 02, 2015 2:24 pm

    BTW:Mr. Curcio dropped the word "Witch" before his title.

    Tube Nube

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    Re: Anybody have experience with Curcio Audio?

    Post by Tube Nube on Fri Oct 02, 2015 8:19 pm

    The trouble with the Curcio plan is that you don't have a ball park estimate of what these mods will cost you. You have to pretty much commit to it by sending your amp away and paying the $100 plus postage.

    If he could give you at least typical price range, then you could compare the costs against getting a newer pre-amp, say, from Roy.

    Of course, if the Dyna pre amp is preferred for reasons of sentiment, or authenticity, or something, then maybe cost doesn't matter much.

    Tube Nube

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    Re: Anybody have experience with Curcio Audio?

    Post by Tube Nube on Fri Oct 02, 2015 8:22 pm

    Of course, perhaps there's a few other options, here on this forum, since you're already a member here. We've got a few technical wizards who build, repair, modify VTA-based amps. I wouldn't be surprised if some of these fellas would discuss your amp with you and give you a better idea of costs.

    Just a thought.

    tubes4hifi
    Admin

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    Re: Anybody have experience with Curcio Audio?

    Post by tubes4hifi on Sun Oct 04, 2015 5:16 pm

    well, it's been about 30 years since I last bought any Curcio products, but based on his email, I would expect that his changes to your preamp
    would cost in excess of $400 in parts and labor, if not more. And likely would reduce it's value from $600 to $200 (yes, you read that correctly).

    PeterCapo

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    Re: Anybody have experience with Curcio Audio?

    Post by PeterCapo on Sun Oct 04, 2015 10:56 pm

    muncybob wrote:
    .....here is his reply from my original inquiry:
    ...
    If you are using your phono stage, I would change the operating parameters of that stage as well plus correcting the RIAA filter.
    ...

    I don't know what he has in mind for the RIAA in this case, but if it is anything like what he has to say about the original PAS, you might want to read the following: http://www.audioregenesis.com/documents/PAS_Phono.pdf
    .

    peterh

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    Re: Anybody have experience with Curcio Audio?

    Post by peterh on Sun Oct 04, 2015 11:49 pm

    PeterCapo wrote:
    muncybob wrote:
    .....here is his reply from my original inquiry:
    ...
    If you are using your phono stage, I would change the operating parameters of that stage as well plus correcting the RIAA filter.
    ...

    I don't know what he has in mind for the RIAA in this case, but if it is anything like what he has to say about the original PAS, you might want to read the following: http://www.audioregenesis.com/documents/PAS_Phono.pdf
    .

    This relates to PAS2/3. PAS4 is totally different, but given the schematics i would say
    that it's fairly close to RIAA and not subject to any mods needed.

    In short i do not think Curcio is aware of the fact that this is a PAS4.

    pmarcin

    Posts : 131
    Join date : 2009-01-20
    Age : 69

    Re: Anybody have experience with Curcio Audio?

    Post by pmarcin on Mon Oct 05, 2015 5:55 am

    I don't see he can correct the RIAA, when it's correct and don't see how he can add the servo voltage additions without altering the circuit boards. I concur with tubes4hifi's assessment.



    tubes4hifi wrote:well, it's been about 30 years since I last bought any Curcio products, but based on his email, I would expect that his changes to your preamp
    would cost in excess of $400 in parts and labor, if not more. And likely would reduce it's value from $600 to $200 (yes, you read that correctly).

    pmarcin

    Posts : 131
    Join date : 2009-01-20
    Age : 69

    Re: Anybody have experience with Curcio Audio?

    Post by pmarcin on Mon Oct 05, 2015 6:35 am

    I concur with peterh
    muncybob wrote:
    .....here is his reply from my original inquiry:
    ...
    If you are using your phono stage, I would change the operating parameters of that stage as well plus correcting the RIAA filter.
    ...

    I don't know what he has in mind for the RIAA in this case, but if it is anything like what he has to say about the original PAS, you might want to read the following: http://www.audioregenesis.com/documents/PAS_Phono.pdf
    .
    This relates to PAS2/3. PAS4 is totally different, but given the schematics i would say
    that it's fairly close to RIAA and not subject to any mods needed.

    In short i do not think Curcio is aware of the fact that this is a PAS4.

    PeterCapo

    Posts : 386
    Join date : 2008-12-05

    Re: Anybody have experience with Curcio Audio?

    Post by PeterCapo on Mon Oct 05, 2015 10:49 am

    Mr. Curcio may very well realize that it is a PAS4.  For instance, in his response to muncybob he referred to it basically being "a solid preamp," though still with opportunities for improvements.  I've frequented Mr. Curcio's forum and read many of his posts, and I tend to doubt that he would think of the original PAS nowadays as being basically a "solid preamp" before having any modifications.

    Be that as it may, I suspect Mr. Curcio would likely just gut muncybob's PAS4 and install his own circuits as opposed to attempting to build anything onto the original circuit board.  On his website, he advertises that he can repair or modify several different makes and models of audio gear, not just the original, classic Dynacos.

    The point of my post about the RIAA thing is to show that Mr. Curcio's claims about the RIAA accuracy in the original PAS are now in serious doubt based upon the convincing Audioregenesis study.  Therefore, it suggests to me that any thought of his "correcting" the RIAA in a PAS4 may likewise be unnecessary.

    muncybob

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    Join date : 2015-04-21

    Re: Anybody have experience with Curcio Audio?

    Post by muncybob on Mon Oct 05, 2015 10:58 am

    An interesting read...thanks! I'm sure he knows what I have is the PAS4 but it would appear he has no experience with it. When he mentioned RIAA correction I was taken back because to my ears the phono stage on this thing is where it truly shines.

    PeterCapo

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    Join date : 2008-12-05

    Re: Anybody have experience with Curcio Audio?

    Post by PeterCapo on Mon Oct 05, 2015 11:03 am

    Right, and, of course, he doesn't really need a lot of experience with it to gut it like a fish and just install his own circuits.

    My suggestion would be to enjoy your PAS4 as it now is and just do one-to-one parts replacements if needed. Seems like it's a pretty nice preamp.

    pmarcin

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    Re: Anybody have experience with Curcio Audio?

    Post by pmarcin on Mon Oct 05, 2015 12:16 pm

    PeterCapo wrote:Right, and, of course, he doesn't really need a lot of experience with it to gut it like a fish and just install his own circuits.

    My suggestion would be to enjoy your PAS4 as it now is and just do one-to-one parts replacements if needed. Seems like it's a pretty nice preamp.

    I concur 1-1 and Amperex 6922s

    muncybob

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    Join date : 2015-04-21

    Re: Anybody have experience with Curcio Audio?

    Post by muncybob on Mon Oct 05, 2015 2:03 pm

    yea, I need to roll some tubes.

    peterh

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    Re: Anybody have experience with Curcio Audio?

    Post by peterh on Mon Oct 05, 2015 5:58 pm

    PeterCapo wrote:Right, and, of course, he doesn't really need a lot of experience with it to gut it like a fish and just install his own circuits.

    My suggestion would be to enjoy your PAS4 as it now is and just do one-to-one parts replacements if needed.  Seems like it's a pretty nice preamp.
    That is a *very good* advice.

    Enjoy the music and buy some records for the money instead.

    muncybob

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    Join date : 2015-04-21

    Re: Anybody have experience with Curcio Audio?

    Post by muncybob on Tue Oct 06, 2015 10:41 am

    No problem there Peter, wife is asking how much more music do we really need. My reply is I'll keep collecting as lng as it still sounds good!

    Still, the curiosity keeps me wondeing due to it's age how much better it possibly might sound.

    PeterCapo

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    Join date : 2008-12-05

    Re: Anybody have experience with Curcio Audio?

    Post by PeterCapo on Tue Oct 06, 2015 10:49 am

    muncybob wrote:

    Still, the curiosity keeps me wondeing due to it's age how much better it possibly might sound.

    If it is gutted and different circuits installed, then you'll never know how an original PAS4 could sound.

    Here are just a few ideas to refresh it and bring out its potential...

    Replace electrolytics 1:1 with low ESR parts of the same or higher voltage rating and the same or moderately higher capacitance.  Polypropylene bypass capacitors on the electrolytics is also a good idea.

    If the coupling caps in the audio circuit are Mylar, replace with polypropylene.

    There are other 1:1 parts upgrades possible: resistors, diodes, volume pot, selector switch, new tubes...

    Just some more food for thought.

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