Dynaco amplifier

[Mr. Ron]

I built a Dynaco ST 70 amp and a PAS 4 preamp back in 1962. I fell victim to solid state electronics and sold it. What a big mistake that was. Dynaco amps have been upgraded with a handful of parts to perform as good as any high end amp, like a Conrad Johnson, or McIntosh. That being said, I am thinking about looking for a used Dynaco amp and improve on it. McIntosh and other high end electronics are way out of my price range, but I think I can handle a Dynaco. I have noticed, they carry high prices, but no where as high as the high end ones. Does anyone here have Dynaco and what are your opinions? I'm trying after so many years of solid state devices to get back into tube electronics, RTR tape and vinyl. I have a big collection of vinyl that I have accumulated over the earlier years.

[Doc B.]

Not sure if you know this, but we design and sell our own tube amp kits. So I'm going to suggest you look into those before you go looking for a used Dynaco. I like to think we have learned a thing or two about tube amp design since the 60's.

https://bottlehead.com/bottlehead-products/

[aragorn723]

If you decide to build a kit from Bottlehead, the directions are fantastic, and if you run into an issue, you can get great tech support here .  I built a Bottlehead Quickie a few years ago, and have really enjoyed the sound (it is based on the 3S4 tube and battery powered).  Lots of great stuff here!  A lot of the folks on this forum have replaced their high end (sometimes even macintosh) preamps with bottlehead ones and enjoyed it more.  Plus you will get the benefit of tinkering with your preamp or amp to make it sound exactly how you would like!  That to me is invaluable (plus bottlehead will help you if something goes wrong-broke my preamp trying to upgrade some caps, and bottlehead helped me figure out what's wrong even though it was my fault 

Dave

[Zimmer64]

The bottlehead amps are very good. I have built 2 and they are in constant use. If you are looking for ST70, you may go here http://tubes4hifi.com/

Michael

[HF9]

I built a Dynaco ST 70 amp and a PAS 4 preamp back in 1962. I fell victim to solid state electronics and sold it. What a big mistake that was. Dynaco amps have been upgraded with a handful of parts to perform as good as any high end amp, like a Conrad Johnson, or McIntosh. That being said, I am thinking about looking for a used Dynaco amp and improve on it. McIntosh and other high end electronics are way out of my price range, but I think I can handle a Dynaco. I have noticed, they carry high prices, but no where as high as the high end ones. Does anyone here have Dynaco and what are your opinions? I'm trying after so many years of solid state devices to get back into tube electronics, RTR tape and vinyl. I have a big collection of vinyl that I have accumulated over the earlier years.

It really depends on what speakers you plan to use. Bottlehead kits are single-ended and intended for relatively sensitive speakers, whereas the Dynaco designs are push-pull and can handle somewhat more inefficient speakers. I've built the ST-35 with the original circuit, the ST-70 with the Tubes4hifi driver board, the MKIII with the triode electrics driver board, and I'm working on an MKIV with a DIYTube board. The ST70 is quite euphoric, the MKIII is a little more detailed and forward, and the ST35 is a great all-arounder. I also rebuilt a PAS pre-amp with the original circuit but modern pre-amps really out-gun it.

The Bottlehead instructions and support are very good, whereas with most of the other kits you have to know your way around a little more. The Bottlehead designs also have quieter power supplies than the 1960s circuits, no surprise there. Third, the Bottlehead kits are safer, no ungrounded chassis or high voltages to worry about. Still, refurbing an old Dynaco (or HH Scott / Heathkit) is it's own kind of fun, I honestly suggest trying both if you can swing it.