Dynaco ST-70?

mmadden28

Is the Dynaco ST-70 a good Tube amp for ~$700? Or are there better out there for the money??

Face

Depends on the condition and mods. Do you have a link to the one in particular you're looking at?

It wouldn't happen to be this one? http://www.audiogon.com/cgi-bin/cls.pl?ampstube&1224698082

mmadden28

Actually no, but the yellow one similar to that looked nice.

I was originally looking at this one - unmodded but restored. http://www.audiogon.com/cgi-bin/cls.pl?ampstube&1224594675&/Dynaco-st-70-fully-restored--u

Not sure how it compares to a tube or SS amp of today for the same value.

F1nut

A true classic.

gidrah

I just had a great reply, but I guess I logged back off.

The ST-70 is a good amp (I have one that I love), but I wouldn't pay that much money without it being heavily modded with the documentation to prove.

There are plenty of amps out there that might be a better option depending upon your needs and wants.

mhardy6647

The ST-70, stock, sounds like what people who make fun of tube amps think a tube amp sounds like :-) Warm, boozy, bluesy, round and a little fuzzy. There are zillions of mods and upgrades; a veritable cottage industry, so I think you can make one sound good. For $700, an ST-70 had better be cosmetically excellent, tweaked with good parts,and equipped with good old European tubes (IMNSHO).

If you want to taste Dynaco amps, the ST-35 is a better-sounding (though unfortunately relatively uncommon) alternative to the ST-70. I recently picked up an SCA-35 (the integrated amp 'version' of the ST-35) and it sounds pretty good. Not quite as wonderful as my EICO HF-81, but the SCA-35 is mostly original (only coupling caps have been changed, AFAIK). Both the ST-70 and the ST-35 have very good output transformers.

Finally... You can buy, and build, an easy-to-assemble ST-70 or ST-35 kit from www.dynakitparts.com for very reasonable prices. EDIT: The base model ST-70 kit, brand-new, is $650. The iron won't be quite up to the quality standards of the vintage transformers, but it'll be quite good.

If I wanted a really fine vintage EL34 pushpull Williamson stereo power amp, I'd look hard for an EICO. Which one was that? HF-87? HF-89? I'd have to check.

schwarcw

I like the Dynaco ST-70, but I would buy this one Here

I know this seller personally. He has eBay feedback of 100% positive for more than 1,000 transactions. He rebuilds Dynaco, Scott, EICO, Fisher, Sherwood and more. I have several pieces from him. He is a true expert in rebuild/refreshing old audio tube equipment. Tell him Carl sent you!

schwarcw

BTW Mr. Madden, he lives close enough for you to pick it up. Probably about a 2 hour drive, it's worth it instead of shipping.

Carl

mmadden28

Thanks all, thats basically the info I was looking for.

hmmm

sucks2beme

My Audio Research VT-60 was $600, and was in very good condition.
I hope that provides an idea what's out there. The AR stuff sounds
more neutral in tone than some other offerings.

Face

mhardy6647 wrote: »

The ST-70, stock, sounds like what people who make fun of tube amps think a tube amp sounds like :-) Warm, boozy, bluesy, round and a little fuzzy. There are zillions of mods and upgrades; a veritable cottage industry, so I think you can make one sound good.

What do you expect for something released in 1959?

I agree, the modded ones can sound much better. I haven't heard a original ST-70, but my Welborne modded ST-70 doesn't fit that description above.

Systems

$700 for a stock ST70 is too much IMO.If it were a Mac MC240 however...

mhardy6647

Face wrote: »

What do you expect for something released in 1959?

I agree, the modded ones can sound much better. I haven't heard a original ST-70, but my Welborne modded ST-70 doesn't fit that description above.

Nor does my Marky modified HF-81, dating to about 1959 as well...

sucks2beme

Time for some research. There's a lot of offerings in that price range.
Finding a Mac might be hard work, but there's lot of decent tube amps out
there in that price range. Take your time and enjoy the trip. If not this one,
a better deal will come along soon. It always does. There's a lot of stock
stuff that's pretty good, and a lot of modded vintage and modded Chinese stuff
that might fall right into your preferred price range.

schwarcw

Mr. Madden, if you are planning to use a tube amp with the LSi9's in your sig, I would recommend using a tube pre-amp, and a solid state power amp. Those LSi9's are a load for an EL34 based amp. These speakers are 4 ohm and not very efficient. The Dynaco would power them, but it may not be as dynamic as you would like. A lot would depend on your listening levels. Just some more food for thought.

Anyone else used a tube amp with the LSi9's?

mmadden28

schwarcw wrote: »

Mr. Madden, if you are planning to use a tube amp with the LSi9's in your sig, I would recommend using a tube pre-amp, and a solid state power amp. Those LSi9's are a load for an EL34 based amp. These speakers are 4 ohm and not very efficient. The Dynaco would power them, but it may not be as dynamic as you would like. A lot would depend on your listening levels. Just some more food for thought.

Anyone else used a tube amp with the LSi9's?

Thanks for the advice. The LSi9s are already being fed by a tube pre and an SS amp--right now I am just considering a tube amp-not seriously looking-however keeping an eye out for a good opportunity while trying to learn what's what for when I am ready. I suppose when I'm ready for a tube amp, that I might get a pair of speakers suitably matched.

What I have read in parts so far is that it's the first watt that counts the most, since it takes a doubling of the wattage to gain 3dB. I am under the impression that Tube amps can drive more with less wattage.

Of course I like to listen loud (but not brain splattering loud (well not all the time anyway).;)

Right now a tube amp is way over my head for me at this point. Just info gathering for now.

Thanks

Face

I'm not sure a ST-70 with LSi9's would be a good match either. I would check out Manley.

organ

Depending on the speakers being used, IMO, the Dyna ST-70 is the best amp at $1k and under. If that was my budget, I wouldn't look elsewhere.
BUT $700 is a lot of money for a stock one which probably needs new caps. They usually go for 400ish (beater, stock) to over $1000 (modded/restored/etc).

Polk's RT speakers sound absolutely amazing on the ST-70. Both could be had for under 1000 which is extremely hard to beat(used speakers, of course).

Things to look for would be the earlier versions with the "A470" transformers.
The sound of the EL34 tubes (used in the ST-70) is one of my favorite.

Many claim the amp to be "slow" sounding. This depends on the loudspeakers being used. I feel like the ST-70 need speakers that are 95db and up to have them cruisin' at high speed.

The Dyna ST-70 will remain in my collection forever. The "dreamy" sound they put out is pure pleasure to listen to. btw, you can buy brand new kits again which is great if you're into DIY. www.dynakitparts.com

Face

Here's my baby.

Right now it's being used in my bedroom, but I may move it back into the main rig to bi-amp.

mmadden28

Face wrote: »

Here's my baby.

Right now it's being used in my bedroom, but I may move it back into the main rig to bi-amp.

That juicy looking picture is not helping me abstain.

mmadden28

So is $700 for a fully restored, yet unmodded ST-70 good?

Face

I paid $100 for my Welborne modded ST-70, but YMMV.

mmadden28

Face wrote: »

I paid $100 for my Welborne modded ST-70, but YMMV.

Thanks that's helpful . Rub it in why don't ya

mhardy6647

mmadden28 wrote: »

So is $700 for a fully restored, yet unmodded ST-70 good?

umm, no. See post #6 above.
http://www.polkaudio.com/forums/showpost.php?p=911215&postcount=6

$100 for a Welborne-ized ST-70 is a pretty good deal :-)
(even if the tubes are Chinese and Russian...)

organ

Face,
Beautiful. I really like the looks on the modded circuit boards that have 4 signal tubes. It looks like a nice city at night. NICE Mac pre btw.

I traded an Onkyo HT receiver for mine.

Madden,
It really depends on on how much restoration was performed. For $700, I would expect a compeletely new front circuit board with quality coupling caps, new set of tubes, new tube sockets, re-wired internally with good wires, new output binding posts, new PS supply caps and a super clean "like new" chassis where it is polished to look like new.

What speakers are you using?

mmadden28

Take a look at the description of the link in post #7 and tell me what you think about the condition of that one. For just a hair above a new kit... Just trying to put this into perspective.
If I went with that one, I would likely follow Carl's advice and drive out to get it, but then again who knows??

Not sure I have plans to purchase ATT, still pondering-And not saying I wouldn't go for some other type either--Already did a lot of purchasing recently that the wife would not be happy about :eek: . No dedicated speakers for it either-I think I'll keep my Tube pre and SS amp with the LSI9's-I'd certainly try the LSi9s on the ST-70 or similar to hear the difference. I have a couple other spare speakers around as well I could try-but nothing very efficient.

Alright so lets say that was the one I was going to get, would I be wasting my money or would that be a half decent deal. Again just trying to get perspective ATT.

Thanks

organ

What do you mean by ATT?

The ST-70 in the link on post 7 is an excellent price for what you're getting. The chassis has been painted along with the transformer casings. The work looks very profesional. Caps and wiring are also above ones that come with the kits.
Noticed the seller is using a 5U4GB rectifier. Don't know if it's a direct substitute of the proper rectifier, which should be the 5AR4. People like to roll different types of tubes on it.

I also had my 70 hooked up to my LSi9's when I first got it. It worked very well for me because I was really into soft vocals at the time. The LSi9/Dyna combo is very, very mellow and warm. Too vintage for a lot of people.

mmadden28

organ wrote: »

What do you mean by ATT?
The LSi9/Dyna combo is very, very mellow and warm. Too vintage for a lot of people.

ATT=At This Time

Thanks

I guess I don't know what Vintage sounds like. I wish I did.

organ

Ok, I'll keep that in mind.

Vintage sound for tubes usually means slow, euphoric, smooth, thick and very warm sounding with some slight roll off in the high frequencies and a bit of flabby bass.

schwarcw

organ wrote: »

The ST-70 in the link on post 7 is an excellent price for what you're getting. The chassis has been painted along with the transformer casings. The work looks very profesional. Caps and wiring are also above ones that come with the kits.
Noticed the seller is using a 5U4GB rectifier. Don't know if it's a direct substitute of the proper rectifier, which should be the 5AR4. People like to roll different types of tubes on it.

I'll throw in a little more info about the seller here. He has rebuilt, modded and repaired many of the ST-70 amps. I think he has two or three currently for sale. I know he has about ten more waiting to be rebuilt. Tell him what you want in the ST-70 and I'm sure he'll give you whatever you want. Transformer type, tube set, colors, plating, special caps, connectors, whatever. Contact him and ask for some recommendations. His quality and price are excellent.

organ

Yup, judging by the pics, he does VERY good work on those amps.

I'm going to get a complete overhaul on mine by my dealer. Gonna stay with the stock design though.