Sources for Dynaco Stereo 70.

Hi folks. I need a project and thought that I might enjoy modding and upgrading a Stereo 70. When I look here on Audiogon, all of the 70s that have been for sale are alread done and completely tricked out. Likewise the auction sites. I have been to the thrift stores as well. So, can anyone suggest where I should look for one? Thanking you in advance for the guidance.
Looks like there are three units in pretty much stock condition available on eBay at this moment, plus one rebuilt. Be prepared to pay though. They are known to be popular and even ones in rough condition don't go cheap.

An alternative is to become an active estate/garage sale enthusiast. You may find one really cheap that way, but you're going to have to go to a LOT of sales before you find one.
If there is a local classified ad publication on the newstands in your area, for buying and selling of used items, place a want ad in it.

If you do so, you might want to word it more broadly, such as "wanted -- 1950's and 1960's tube hifi equipment, such as Dynaco Stereo 70." That way you may just turn up an even better treasure!

-- Al
Not knowing how much of a project you're looking for, take a look at one of the Dynaco Stereo 70 kits, which are updated and improved. I'm currently assembling a version of this amplifier, which I bought on Ebay, also available from ( The parts and assembly instructions are of high quality, and has been a good winter project for me. Buying an old unit for updating sounds like a real PITA, and who knows what you'll end up with. The XFMRs, components, and driver board are of higher quality in this kit, and resolve known problems with the originals. The chassis is an attractive polished stainless steel too.

Good Luck.

It seems the cat has been out of the bag a little while on these. I've seen several want-ads (even here) with buyers offering $250+ for ST-70's in any condition, presumably to rebuild and sell for much more.

I like Howard's suggestion, and second Al's suggestion of opening up to other brands. I've come home with a couple of less choice (but still worth working on) pieces of tube equipment from yard/church sales for very short money. A starter project such as one of those will also give you a better appreciation of what's involved, and give you a chance to experiment with various aspects (tools, techniques, parts etc.) of the restoration process, and by the time you DO happen upon something like an ST-70 at the right time and place, you'll either be ready to take it on, or will have lost interest. I'm somewhere in between those two endpoints.
Marty, I built an ST70 over the summer, and am delighted with it. It was fun, fast, and I often stay up late at night with a smile on my face listening to it. Of course, it's not the most powerful amp out there, or anywhere near it, and the low frequencies leave a lot to be desired, but in all honesty, I'm not really sure any of the amplifiers I've been around really surpass it in the midrange or in the total sense of musical enjoyment.

It took me getting an old set of 7199 drivers before it really lit my fire (the Sovteks really suck, and I've never heard a bigger tube improvement in audio than rolling this tube), and I'm told I need to upgrade the 5AR4 rectifier as well, though I haven't yet done that. The only upgrades I did were the input jacks, loudspeaker terminals, and power supply cap, all of which I got from Bob Latino, everything else came from Kevin. I also bought an upgraded driver board kit from Bob, but I'm so satisfied with the amp currently, I never felt the need to assemble it or make a few of the tweaks such as converting it to triode operation (more romantic) or lowering the values of the cathode bias resistors (supposed to really open up the sound). Obviously, I'd contact Kevin at DynaKit parts and/or Bob Latino about getting one.

Interesting to note how far we have not come in the past 50 years.
Thanks you all for all of the great insight and guidance. It's always great to participate in this forum to get a diversity of ideas. I have my work cut out for me.

I should clarify that a friend gave me a PAS preamp and I have done about half of the mods and upgrades that I want to and I am shocked at the performance. So I was just looking for a matching amp. I am comfortable with a soldering iron and have a good feel for parts selection, so I don't find these things too daunting.

Joe, pretty cool story, especially coming from someone with the broad experience with gear that you have. Any chance you can e-mail me some photos?

Warmest regards to all of my audiobuddies!

Marty Kohn
Portland, OR
Marty, I'll snap a few photos and send them off to you.

One thing that I didn't expect at all was that my wife was really keen on the look. It's stainless steel, and good bit smaller than the average 17" component, both of which made her happy. Personally, I don't consider it a good looking piece of kit, but it's not offensive in the way a lot of the Chinese stuff looks - especially, after a couple of years have passed.