I would tend to agree with that assessment. BTW, please tell your friend that I keep his book (The Tube Amp Book) close at hand!
I ran my Stereo 70 for many, many hours before I did anything to it beyond replacing the tubes, because one of the 7199's was defective and the EL-34s were a mismatched bunch of questionable lineage.
I eventually replaced the can cap, not because it wasn't working, but because a drop-in replacement of new manufacture became available and I really had no way of testing the actual capacitance of the sections on the original one at operating Voltages. IIRC, the original was an AeroVox, and as far as I know, it is still a functional part.
The Selenium rectifier was somewhat of a moral dilemma once I read that one that gives up often spews toxins into the air. Since I would be using the amp around others, I wasn't comfortable exposing them to an unknown risk. So, as a compromise, I left the Selenium in place, but simply took it out of service. Again, I had played the amp "as is" for hours at this point.
My decision to retain as much of the original amp as possible centered on its heritage. When I first acquired it, I naturally wanted to inspect it "under the hood". When I turned it over and removed the bottom plate, I discovered a name and date scratched into the underside of the chassis with an engraver. The date put it at Christmas of 1959, but the name was of an old acquaintance since passed who had owned the first music store in my town to sell drums, guitars, and amps!
At that point, I knew that fancy new driver and PS boards were out, and hunted up the NOS and new tubes I needed, set the bias, and put it into service!
Yours looks to be in very good shape, physically better than mine was.
The link should get you to a .pdf of the original manual, and the site has lots of good stuff:
www.curcioaudio.com/st7_mnl.pdf Happy New Year!
