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    In the spirit of "back to the future"...

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    Tube Nube

    Posts: 332
    Join date: 2008-12-07
    Age: 50
    Location: Calgary, AB

    In the spirit of "back to the future"...

    Post by Tube Nube on Sun Dec 07, 2008 5:16 pm

    . . . I'm interested to upgrade to by going forward to the past.

    I've long been interested in switching over to tubes. A friend recently introduced me to Dynaco (on the net, he no longer has one), and I'm captivated.

    From what I'm reading, the VTA modified ST70 would be a very nice way to go. I'm not yet ready to take the plunge, though -- I'm hung up on the pre-amp.

    My sources are a Linn Sondek (with Basic Plus arm, Adikt cartridge), and also a CD player.

    What do I need? I wonder if anyone has some suggestions? I thought about a Curcio Sarah phono pre-amp, but read elsewhere it's not for the novice buider. (I haven't picked up a soldering iron since highschool electronics)

    Thanks in advance,

    Brenton

    Bob Latino
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    Posts: 1909
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    Location: Massachusetts

    Re: Preamp

    Post by Bob Latino on Sun Dec 07, 2008 12:05 pm

    Brenton,

    A nice preamp for the money is the Transcendent Grounded Grid preamp. ($499 in kit form). I had one until about a year ago. It was very quiet with excellent quality sound. I only sold it because I wanted a preamp with a remote and the Transcendent doesn't have a remote. The Transcendent is an easy build. There are only two boards, three tubes and the wiring between the boards. A novice could put it together.


    Photo of the Transcendent Grounded Grid preamp below ...


    Link > http://www.transcendentsound.com/preampkit.htm



    A lot of people like a Dynaco PAS preamp to go along with their Dynaco amp but IMHO the PAS-2 or PAS-3 must be heavily modified to sound on a par with some of the more modern preamps.

    If you ever get an ST-70 the two things to do are to update the power supply with a new quad cap and upgrade the bias supply by replacing selenium rectifier with a UF1007 diode. If you just want to do the bias supply and the quad cap then www.dynakitparts.com sells both. If you want to do more extensive modifications I would replace the driver board. The old driver board was made of an inexpensive bakelite material with open solder traces on the bottom. It was prone to cracking and overheating. Nearly all the original Dynaco ST-70 driver boards are black under the 7199 driver tubes due to excess heat. If you DO replace the driver board with an updated board then the VTA driver board is IMHO presently the best updated driver board out there. If you stay with the old original board then you are stuck with the 7199 tubes. These 7199 tubes are not made any more and the remaining supply is slowly drying up and prices keep rising on 7199 tubes. A NOS (new old stock) RCA or Sylvania 7199 tube can go for $30-$40. If you go with the VTA driver board then you use the inexpensive and readily available 12AT7 tubes. You also get the advantage of individual biasing of the four output tubes and an on board bias supply. The VTA also has it's own power supply on 4 electrolytic caps on the back of the board. By having its own power supply it doesn't have to steal B+ power from the quad cap. The quad cap is then free to just run the two power hungry output transformers.


    Photo of VTA driver board top and bottom below - a mil spec board with no open solder traces



    Bob

    Tube Nube

    Posts: 332
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    Re: In the spirit of "back to the future"...

    Post by Tube Nube on Sun Dec 07, 2008 1:19 pm

    Bob,

    Thanks so much for this most helpful feedback. "Feedback", heh heh, a little bit of an audio pun there... (Sorry!).

    As soon as I've written this note, I'm off to look into this pre-amp you 've recommended. This is very encouraging that a nice sounding amp can be had at a good value and built by a novice.

    Maybe I should be asking you this in an email, rather than on the forum board, but do you still carry the ST 70 kit with the VTA mod you mentioned (which I've also read about elsewhere)?

    Brenton

    Bob Latino
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    Posts: 1909
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    Re: In the spirit of "back to the future"...

    Post by Bob Latino on Sun Dec 07, 2008 3:51 pm

    Tube Nube wrote:Bob,

    Thanks so much for this most helpful feedback. "Feedback", heh heh, a little bit of an audio pun there... (Sorry!).

    As soon as I've written this note, I'm off to look into this pre-amp you 've recommended. This is very encouraging that a nice sounding amp can be had at a good value and built by a novice.

    Maybe I should be asking you this in an email, rather than on the forum board, but do you still carry the ST 70 kit with the VTA mod you mentioned (which I've also read about elsewhere)?

    Brenton

    Hi Brenton,

    I do still carry the complete Dynaco ST-70 kit with the VTA driver board and triode/pentode switches. If you need more info about the kit just Email me directly at > Bob01605@aol.com or visit my web page on the tubes4hifi web site at the link below.

    http://www.tubes4hifi.com/bob.htm

    Bob

    Tube Nube

    Posts: 332
    Join date: 2008-12-07
    Age: 50
    Location: Calgary, AB

    Re: In the spirit of "back to the future"...

    Post by Tube Nube on Sun Dec 07, 2008 9:45 pm

    Bob,

    Thank you for this.

    EMail sent

    JunkyJan

    Posts: 100
    Join date: 2008-12-09
    Location: BC, Canada

    Re: In the spirit of "back to the future"...

    Post by JunkyJan on Mon Dec 08, 2008 10:20 pm

    Hello Tube Nube

    For what it's worth, I am running one of the Latino ST-70 amps with a NAD 114 pre-amplifier. The NAd is a great pre-amp but IMHO it does not live up to the potential of the ST-70 power amplifer. For instance, I can detect a VERY SLIGHT tendency towards sibilance on female voice - which is totally absent when I drive the ST-70 directly from a CD player, or through a passive preamp.

    The Grounded Grid preamp mentioned looks great - I think staying with an all-tube layout is best.

    Also, if you do buy an ST-70 kit, you may as well go the whole hog and get the upgrade caps as well...

    -- JunkyJan

    Tube Nube

    Posts: 332
    Join date: 2008-12-07
    Age: 50
    Location: Calgary, AB

    Re: In the spirit of "back to the future"...

    Post by Tube Nube on Wed Dec 10, 2008 12:36 am

    Jan,

    Hey, thanks for this feedback.

    You know, NAD was my first introduction to real HiFidelity, back in...ohhhh, 1980 or 81, if I recall correctly now. A friend of mind had NAD, Nackamichi gear run through DBL speakers, which was the most astoundingly awesome audio gear I had ever heard to that point. I was really amazed how much better it sounded than "mass market" gear, which I know is a pejorative term these days, but let's face it, it really does give good value for money...at least compared to the early 70's.

    Anyhow, that started me a salivating, way back when.

    I'm delighted by your reports of the "Latino 70". I took the plunge today, and ordered up an ST 70 from Bob's shop, replete with the updated caps and the KT88 tubes. I've been reading good things about the grounded grid pre amp, so will probably be calling about that tomorrow. I'll be sure to report back hear about how it all comes together, though that won't be til early-mid January, since I'm about to be outta town for the holidays.

    I have to say Bob was most helpful to me both on and off the forum here with information and recommendations not only about the ST 70, but others things like the pre amp questions I had, cabling issues, etc.

    My adventure into Tubes, so far, has brought me in touch with good information and good people. I think I'm going in the right direction!

    Brenton

    JunkyJan

    Posts: 100
    Join date: 2008-12-09
    Location: BC, Canada

    Re: In the spirit of "back to the future"...

    Post by JunkyJan on Fri Dec 12, 2008 1:19 pm

    Hi Tube Nube

    I have two Dared MP-7 tube amps (don't ask why I have two of them - it's a long story). The MP-7 is a Single-Ended Triode design, and I expected the ST-70 to be LOUDER than the Dared, but not as detailed. I mean, that is supposed to be the big difference between Single-Ended and Push-pull designs, right?

    Turns out the Latino ST-70 is every bit as detailed as the SET amps - and then some. But now I have tons of headroom to spare as well (I listen to just about any type of music - Jazz, Electronic Rock, Dinosaur Rock, Classical) and I have become an ST-70 convert. Beats everything I have heard so far in a price range up to about $3,000 (well, I assume so - I haven't had the oppurtunity to listen to amps costing more than that yet)

    I share your enthusiasm for the NAD amps, the 114 at the time it was great, but the VTA front-end ST-70 is good enough to show up deficiencies in other parts of your system. I really need a new preamp...

    I think what baffles me most is the fact that the basic design dates back so many years, and with a litte bit of TLC plus some upgrades, still blows the pants of many modern designs.

    Regards
    -- Jan

    Tube Nube

    Posts: 332
    Join date: 2008-12-07
    Age: 50
    Location: Calgary, AB

    Re: In the spirit of "back to the future"...

    Post by Tube Nube on Sat Dec 13, 2008 3:39 pm

    Jan,

    I'm delighted to read your experience of the "Latynaco" 70 (Sorry, Bob, hope you don't mind!), especially since I've committed myself to one.

    I'm always tickled and intrigued by the discovery and rediscovery that new and complex is not necessarily best. When I got interested in HiFi about 20 years ago, I was surprised then to learn that simple designs with a minimal number of high quality parts was the goal. Elegant simplicity! Nothing exemplifies this better than tubes, I think. And it completely thrills me that such a retro thing as tube electronics happens to have sound characteristics that are so sweet to the ear and, arguably, unsurpassed by "modern technology." Sometimes the wheel doesn't need to be re-invented.

    Guess I'm a retro kinda guy, so I might be biased.

    I've taken Bob's advice, from above, and have taken a hard look at Transcendent pre amps and phono pre amps. Reviews found here and there on the web are very strong. Also, the kits are reportedly quite straight forward to build.

    I look forward to reporting back here on what I discover with the new gear. What I will be replacing is a Naim Nait 2 integrated amp that I've had since 1992, if I recall. Think my son could use that one next year at college.

    Cheers,

    Brenton

    tubes4hifi
    Admin

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    Re: In the spirit of "back to the future"...

    Post by tubes4hifi on Sat Jan 03, 2009 6:34 pm

    Brenton (tubenub)
    if the spirit of DIY, the GG Pre really is a great preamp, I bought the one Bob used to own, as I used it to evaluate and compare about a dozen different tube preamps in my quest for the best "bargain" available for a new tube preamp kit, other than buying old 30 or 40 year old classics.
    If you're into building your own completely, rather than a kit, (different types of people, I love kits, I also love creating everything from scratch) then I can offer a couple of very good alternatives. For one, the GG Pre is line stage only, if you want a phono preamp they also sell a great phono preamp for an additional $650, as a kit.
    I also evaluated and have have a new usused GG Pre chinese clone PCB fully stuffed, just needs connection to a transformer, volume control, input/output jacks, and a chassis. I put lots of preamp PCBs into an old PAT4 chassis because they often go for about $30-50 on ebay.
    My other suggestion if you're looking for a COMPLETE preamp (phono, line, preamp) is my VTA SP6 PCB for around $250 complete kit, just add a chassis (again, stuffs nice into an old PAT4).
    One of my customers was also evaluating several tube preamps, and had purchased 6 or 8 classics, including an Audio Research SP8 on ebay for $1000, and I loaned him my GG Pre and my VTA SP6.
    He wrote back and told me he couldn't believe it, he liked them both better than the Audio Research, one of the best classic tube preamps made, but he decided to build my complete SP6 into my custom chassis for around $800 invested, and has never been happier. It was alot of work compared to a ready to go kit (I haven't written a decent manual for my SP6 yet, stuffing a PCB is easy stuff, but all the various connections and mechanical assembly work can be a drag if you're not into that.
    Just thought I'd offer up these alternatives to anyone searching for the best deals on tube preamp kits!
    Roy www.tubes4hifi.com/pre3.htm

    Tube Nube

    Posts: 332
    Join date: 2008-12-07
    Age: 50
    Location: Calgary, AB

    Re: In the spirit of "back to the future"...

    Post by Tube Nube on Mon Feb 16, 2009 8:47 pm

    Hi Roy,

    Sorry I didn't notice your message til it was too late, and I'd ordered the Transcendent GG.

    If I find myself itching to build another pre-amp, you can expect me to give you a call.

    You Dyna-Guys give terrific service and assistance, by the way.

    Brenton

    Tube Nube

    Posts: 332
    Join date: 2008-12-07
    Age: 50
    Location: Calgary, AB

    Re: In the spirit of "back to the future"...

    Post by Tube Nube on Thu Feb 26, 2009 11:07 am

    While I commented on my progress in another thread with Junky Jan, I wanted to post an update on this thread I started back before Christmas.

    Mission Accomplished!

    First thing I did was obtain the ST 70 kit from Bob, with the VTA board. I also went for the upgraded PIO caps, and selected the KT 88 tubes. I was persuaded not only by the value for the dollar, but I frankly like the beefier look of these tubes over the standard ones.

    The Dynaco was an easy build for a guy who hasn't done much soldering since highschool (27 years and counting). Fortunately some things never change!

    I made a few mistakes and caught them all. Usually you can't help but catch your mistakes, since, if you attach a wire in the wrong place, it becomes obvious on a subsequent step when you're told to make a connection to a spot that's already occupied.

    The instructions are complete, well laid out, easy to follow, and easy to back track -- to find those mistakes! Also, Bob Latino is readily available if you need any help, and it has to be said that he's quick and generous in his customer support. In my experience, he was exemplary in all aspects from the enquiry stage, through ordering, giving support during the build, and offering other helpful suggestions on related matters.

    When finished, the amp looks simply great, and not the least bit home spun.

    The sound of this amp is magnificent. Detailed, warm, soothing. "Soothing"? I know that's not audiophile lingo. Wait, ok, the highs have a distinctly nutty palate, and the lows have a crisp finish that would make even a stripper blush. Hmmm. I don't think I quite have the language, but you know what I mean.

    There really is satisfaction in having built it myself, and I encourage others not to hesitate. Something more: There's a loose connection in my new DAC. I was nervous about putting my fingers inside it before I built the ST 70. I have since felt no hesitation about going in, poking around, and re-soldering the pins of the SCR that proved to be the culprit.

    In addition to the ST 70, I followed Bob's suggestion, and looked into the Transcendent Pre amp. It's highly recommended all over the place, so I went for that one, as well as their phono stage.

    So, to sum it all up, I am greatly gratified to have a truly wonderful stereo that I've built myself, saving thousands of dollars, learning valuable lessons and dusting off some dormant skills in the process.

    There is not one single down side to any of this. No regrets or equivocations. Now, how often do you get to say that?!

    Brenton

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