Dynaco ST-70 totally restored vs Dynaco ST-70 Kit


Hi Everyone, I'm planning of buying a Dynaco ST-70 but I don't know which one sound better, the Dynaco ST-70 totally restored vs Dynaco ST-70 Kit(both are on sale here in Audiogon right now). I'm also thinking of Primaluna Prologue amp. How does this sound compared to the Dynaco?
pinoy6

Showing 2 responses by amandarae

I too use Mullard El-34's/6CA7's. I have accumulated 3 pairs all NOS and should be enough. Took me a while to shop, test, and burn in to see if it holds bias current to arrived at my "set". I never had any luck with the metal base ones though (Noisy and un-stable). Oh, btw, I highly recommend to have a reliable tester when buying NOS EL-34's.

FWIW, I never considered my power tranny as "very hot" when operating. I just got lucky perhaps because my unit is pristine (you can tell signs of burning looking at the original enamel paint of the power transformer and also how the original paper base input board looks like inside). I bought mine for $295 way back with original cage, Mullard 5AR4 rectifier, RCA 7199 drivers and Mullard El-34's and all test great.

You can see my unit on my system page here (Winged-C Output tubes) with the Curcio input board with Yageo metal film resistors, Orange Drop caps, and 6922 driver/splitter tubes. I was thinking of replacing the input board caps (from Orange drops to PIO's) but really like what I am hearing so I kept it as it is.

I tried my amp on Magnepan(1.6), Bozaks, Fostex base MLTL, and now my Altec 604's in OB and sounds really nice (except on MG 1.6 where I can only listen at low levels).
I have a friend who has a Polk Audio Vintage speaker (big ones with 4 woofers and 4 HF drivers) and so happened to try the ST-70 there, it sounds pretty nice. My friend wants to buy my amp on the spot. I replied by saying to give me a couple of weeks (I want to shop for a comparable unit to replace the one I have but all I saw during that time are not as mint). That was almost three years ago. I still have my amp.

One other thing, in mono mode (using mono cartridge, and phono preamp), the ST-70 will surprised you thinking that you bought a mega-dollar amp even if you use Winged-C (highly recommended provided that you burn it in for about 12 hours before critical listening)instead of the Mullard 6CA7's.

So in retrospect, give me an Original ST-70 or give me a different amp. Life is too short to waste time on copycat's.

Oh, with regards to "whatever his name" selling kits for the ST-70, follow the link below. If this is not "self promoting" post, I do not know what it is.

[url]http://db.audioasylum.com/cgi/m.mpl?forum=tubes&n=208085&highlight=bob+latino&r=[/url]

In a public forum, is it wrong to post something good about what you are currently selling? I do not know.
am considering a stereo 70 myself. i will only buy an original, stock stereo 70. if i want more "resolution", i'll buy another amp.

why take an orange and turn it into an apple, when you can buy an apple ?

Me too! The power tranny in the original model is fine, no need to step up to a larger rating. if not, why do they last more than 20+ years and counting?

For me, I am bias to the true original output transformers the ST-70 uses. I agree, that the input board needs to be replaced (I use one with 6922 drivers) as well as the power supply main caps (if not replaced already!) and the selenium rectifier. I heard and compared other ST-70 wannabees (not the original power and output transformers) and to me, there is no substitute for the original.

My opinion only.