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.