Dynaco ST 70

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  • 11-05-2006, 06:54 AM
    tin ear
    Dynaco ST 70
    Has anyone done this mod?
    http://www.avahifi.com/root/equipmen...uild_plans.htm
    Or the 70i kit or the Ultimate 70 kit?
    Any comments, complaints, raves?

    I am fortunate to find myself the new owner of a restored ST70. I'll use it like it sits -- until the warranty runs out. After that... :idea: :ihih:

    jon
  • 11-06-2006, 06:34 PM
    tin ear
    Anyone tried the Curcio Audio mods?
    http://www.dynaco-doctor.com/dynadr_3.htm
    ok
    jon
  • 11-11-2006, 07:40 AM
    likeitloud
    I have researched both of those shops after buying 2 Hafler vintage stereo amps, a
    DH220 115wpc and DH500 255wpc. Both amps worked in stock form, and was very
    impressed with how musical they were, out playing a $1200 Rotel 1090. That went
    to ebay, and the Haflers, after much reaserch went to musical concepts. They also
    upgrade the Dynaco chassis. They have 3 "levels" of performance for all budgets.
    Simple front end mods, rca upgrade, binding post etc. The DH220 was around $650
    for caps, rectifier upgrade. The DH500 was upgraded to dual mono, with the same stuff
    done as above. I took these amps to a shop that is a Macintosh/B+K vendor, repair
    dealer, and had them bench tested, the 220 is 132wpc, and the 500 312wpc! The
    guy told me to get that kind of performance from him would cost over $4000, for 1
    not 2 amps. Total cost, including original cost of amps $2200 and some change.
    My advice, do the upgrades, I've heard dyna's in stock form, and they rock, another
    Hafler product, upgraded, they will compete with any tube amp out there, no matter
    who you have do it. Hook it up to some vintage monitors, and your set. These curently
    drive my HPM100's, later model 200wpc, and surrounds. I found out one thing, power
    is everything, music is all I can say, very tight and crisp, is the only way to discribe
    it. Good luck.
  • 11-11-2006, 07:13 PM
    tin ear
    Thanks, LiL
    Quote:
    My advice, do the upgrades, I've heard dyna's in stock form, and they rock, another Hafler product, upgraded, they will compete with any tube amp out there, no matter who you have do it.
    Good advice. That's what I've read elsewhere too, while furiously searching the net for Dyna info. I'm a DIY kinda guy, so I'm looking for mods in kit form -- probably. A lot of these kits look like they're very well spelled-out for the DIYer.

    Thanks for the link (now bookmarked); I'll look into that soft-recovery SS rectifier for the ST-70 (more power :ihih:).
  • 11-12-2006, 05:38 AM
    likeitloud
    Quote:
    Originally Posted by tin ear
    Good advice. That's what I've read elsewhere too, while furiously searching the net for Dyna info. I'm a DIY kinda guy, so I'm looking for mods in kit form -- probably. A lot of these kits look like they're very well spelled-out for the DIYer.

    Thanks for the link (now bookmarked); I'll look into that soft-recovery SS rectifier for the ST-70 (more power :ihih:).
    Let me know how it goes, and BTW, what speakers will it drive? Later
  • 11-12-2006, 08:48 AM
    tin ear
    Right now it's driving PSB T-45s pretty nicely. IIRC they are 88-89 db efficient.

    I also have an old pair of KLH PR-950S 15" 4-way speakers that sound very nice with this amp, which is interesting because they are not very nice speakers. (Don't know efficiency.) And to think -- I was considering tossing them. :yikes: Just goes to show: never throw anything away.

    More efficient speakers would be nice, but some things may have to wait until after Christmas.
  • 11-12-2006, 09:39 AM
    kelsci
    Years ago, I built an original ST-70. I found it a fine power amp in conjuction with the Pas 3S. Nice professional like sound.
  • 11-12-2006, 10:22 AM
    tin ear
    kit
    Someone, I forget who, is offering a modernized (read modded) ST-70 clone in kit form for ~ $650. Not that bad a deal, considering what I paid for this resto/stocker. I'll look for the link...
  • 11-12-2006, 11:11 AM
    tin ear
    kit
    OK, it was on Ebay:
    http://cgi.ebay.com/ws/eBayISAPI.dll...m=110051659014

    I've not been able to find its homepage, though while googling, audiogon popped up as having ads for this product by Amplitube. google: amplitube dynaco

    Ah, here we go - audiogon:
    http://cls.audiogon.com/cgi-bin/cls....ube&1166204476
  • 11-13-2006, 03:37 AM
    likeitloud
    Forgot about audiogon, though there classifieds are usually very highend, and not
    usually geared toward vintage stuff. As far as efficient vintage speakers, the ones
    I've used became that way with lots of EQ tuning, and of course the amp helped
    in that area also. Keep us posted on your amp upgrade project. Later.