Thanks, hehe...reading on some interesting material on newer Dynaco ST 70 that were made in the early 90s. In 1992 a new Dyanco ST 70 was selling at 1095.00 USD. Wow !
Yes, I have listened to newer Dynaco ST70 from late 80s/early 90s. Used solid state rectifier instead of tube. Sounds a little rougher. (it was a nice Mullard tube retifier, very nice..NOS Mullard 5AR4 is about $200 USD each now) They also changed the driver tube 7199, cuz it's no longer in production. The out put transformer is no longer hand wound with precision. It sounds more modern lol..... The pre-80 Dynaco ST70 is not hard to find and they are better. With proper modification, can go head to head against Marantz 8B ! (8B still has an edge unless you are very very good tech and a music lover/hi fi fan who knows about the ST 70)
Mine was one of a kind overhaul plus modification. Film caps, metal resistors, good power choke and nicely shielded..You don't really see that in the market. People who can spend that kinda time to do it if they know how, hehe....will keep it. Why I gave it to my brother in law instead of selling it. Few years later, put in new Mullard EL34 tubes, was nice. This particular amp will most likely kick 8b's arse with the Chinese tubes, after 100 hours of burning in. As we all know, lots of premium tube amps are based on the ST 70's design lol...
補充內容 (2013-11-13 00:58):
The 6AN8A driver tube can replace 7199, about same performance, but different pin assignment. I heard that 6GH8A does the same too.
Dynaco ST 70 amplifier undergoing THD measuements. Measurements are taken at 20, 25, 30, 2KHz and 20KHz using Tektronix SG505 oscillator and AA501 distortion analyzer.
I do not know how this is theoretically, mathematically, or realistically possible. A 35 watt class AB became 28 watt class A by changing the "Q" point (situation point). Class A's theoretical limit is 50% efficiency, about half in real life. 10 watt of class A power is more or less like it.
樓主: 柒喜
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發表於 2013-11-12 18:20:08
發表於 2013-11-12 19:53:11
果然好膽机