Dynakit 70 Stereo Question


I recently bought a house and found two Dynakit 70 Stereo amps? in the attic. I don't know what I've got and am looking for guidance and some education. I can see tubes through the cover and thought there might be some interest from collectors.
DenverMax
denvermax
These amps have been a popular and relatively inexpensive way to obtain a tube amp with moderate power. The design dates back to the 1960's and there were many of these produced. However, IMHO the sound is the old school tube sound, which means rolled off in the high frequencies and very "warm" sounding. These amps don't have nearly the collector interest of, say, the old McIntosh or Citation tube units. I have a couple of refurbished ST70's of my own sitting in storage.

If your units have been sitting in an attic for years, subjected to extreme heat and cold, the passive components (resistors, capacitors, switches, etc.), which were never high quality to begin with, have almost certainly deteriorated to junk status. That means the only real value might be the chassis and the transformers, which is a fair starting point for a total rebuild. That won't be hugely expensive for somebody who is willing to do the work.
If the tubes are original and test good they may be worth more than the actual amps.
Denvermax, Maybe it was meant to be for you to have these.
There are a few very respected qualified technicians that specialize in these and can bring these up to better than new performance. A great sounding system can reasonably be built around these if you are adventurous and patient.
Contact Jim McShane about his Mods for this model.
As Jakegt3 points out, they are not worth that much as is.
On the other hand... your new system may become the most important thing in your life and your sole reason for living like SOME of the people around here... HA
DONT PLUG THEM IN! They need some care before powering up on a Variac. With that said, look around for Dynaco ST-70 to get an idea. These are great amps but most likely will need restored. You could get anywhere from $200 to $700 each depending on condition.
As Jjrenman said, the tubes could be worth a bundle. If you take these in for service, don't let them keep the tubes if they tell you they are no good...
The amps with cloth-covered wire on the transformers go for more. Otherwise the chassis must not be rusted.

These amps have plenty of bandwidth and fixed up properly will give any Mac or tube Marantz a run for its money. The output transformers in the ST-70 work very well.

The amps can be monostrapped, doubling the output power. Instructions on how to do so are in the ST-70 manual.
Two Dynakit ST70s in your attic are a real find! If you choose not to keep them, they'll certainly fetch you a nice windfall on a site like Audiogon, ebay, etc.

In my opinion, the ST70 has superior tone to the vast majority of amplifiers, tube or solid state, marketed today. Of course, they're neither the last word in power nor bottom-end, but there's a couple novel and dirt cheap methods to bring the latter up to modern standards. In the end, I feel the ST70 is one of those products that shows how far off the road high-end audio actually wound up.

If the condition of the chassis are not to your liking, you can always purchase new polished stainless steel units for about $125 at http://www.dynakitparts.com/
Kevin, does a phenomenal job with the polish. His previous iteration was great, but since going to a new method about two years ago, he's taken it up maybe two more notches. Outside of tubes, he obviously also sells anything else you would need to get your amps back to where they need to be.
As in life, condition is everything. If you sell, but sure to make no representation as to functional or operational condition. If an e-Bay sale, safest to say sold as parts only. If stored in an attic, the temperature would often be of the extremes, making condition very problematic. As for sound, I have knockoffs of the design and they are great sounding amps.
Thanks to all for taking the time to respond! Your great comments, suggestions and insights are very much appreciated. Now I have some thinking to do...maybe a new hobby.
DenverMax
Another idea is to send the these amps to Will Vincent he gives you credit for original transformers. Will's Stereo 70 and Triode Stereo 70 are great sounding amplifiers, and his build quality is a work of art...