@quincy I have always wondered if vacuum tube technology was abandoned prematurely (for solid state), and never fully exploited to its full potential?
Vacuum tubes were not abandoned but slowly pushed aside. However the majority of reciever manyfacturers like Fisher, Sherwood, Marantz, Pioneer, Kenwood, Heath, Knight and Lafayette all went to SS sooner than they should have. Of that list I would say only Marantz made good on the change-over in that their early SS gear. Their early SS gear is quite good where the other early SS gear was quite bad. Kudos to Sid Smith who did a very good job to make the Marantz 7T sound as the 7C. However the current value of each does not reflect this because tubes are favored. Both 7s are quite good.
Other early SS designers were Dawson Hadley of Marantz, Jim Bongorino of SAE then GAS, Quatre was horrible, Bob Carver offered power and value but not good sound. Crown was ok, Mac Intosh made some great Autoformer SS amps (see my link via my profile)
In the early ARC preamps up to and including the SP-6 Bill J stole the Marantz 7 circuit topology, added a very unrelaible, poorly regulated power supply. Bill Johnson did nothing I find interesting and just made things worse in every way as time went on. CJ, I'm sorry, never impressed me. Two Economists do not make an EE. Getting them to talk about circuits is a non conversation. Their amps are pretty classic circuits. Its not that you have anything bad but frankly a Marantz 8 is hard to beat. Really really hard to beat. I cant even say I beat it with the RM-9 but I did give more power. I don't want to over do it but Sid Smith was a far better engineer than any of his contemporaries. A lovely man. I met and interviewed both him and Saul Marantz. Perhaps I should publish the tapes. The tube HK Citation amps have some serious flaws.
Who else shall we talk about? The RM-1 was way ahead of its time and I would love to have it reviewed if anyone wants to review legacy products. It is the first preamp to use the 6DJ8, is DC coupled, No output capacitor, response down to 0.1 HZ. Sadly ended by the folding of Beveridge ESLs. I have considered re-introducing just the line stage to sent to John Atkinson. He has never measured a line stage that does what the RM-1 does. Pardon my enthusiasm, but its really special.
If you want to give me a list of companies for a yes/no I would be happy to go down it. Some of the no’s will be no, no, no. like Counterpoint who rightly went bankrup. Sometimes the world takes care of itself. Counterpoint was a group of nasty people making a horrible product.
In short, some companies made a good transition some not. Current tube amps have some interesting ideas but none that really impress me.
