The CJ tube amps were a mono pair of Premier 16's. Bob Carver was able to achieve an excellent null using his 1.5 amp. The Stereophile crew then listened to the modded 1.5 and the CJ 16's and found them to be indistinguishable! A rather remarkable feat! Carver then applied the mods to production 1.5's - hence the "t" designation. He then did the same thing with a pair of Levinson ML2 monos (class A 25 watts). These mods were incorporated into a new series - the TFM's (Transfer Function Modified). I have one - a TFM 125cb (calibrated). It is an excellent sounding amp and drives my KLH Nine full-range electrostats with ease - a difficult load! It also works well with my Ohm Walsh Sound Cylinders. Does the TFM 125cb sound like a pair of Levinson ML2's? Who knows? Not having ML2's on hand for an in-room test ...
Educate Me
I would like to tap into the historical knowledge of the group. Back in my twenties I was a hungry enthusiast and a devout reader of Stereophile Magazine. I recall Bob Carver's challenge to the Stereophile staff that he could build an amplifier that would exactly equal in total sound the best amps being made at the time at a fraction of the cost.
Stereophile took him up on his challenge and I seem to recall they chose an anonymous high end amp which was later identified as Conrad Johnson as the target. They both agreed upon a fairly complicated null test that would identify any differences between the amplifiers and used a 3rd speaker that would literally replicate any sound, including any distortion, between the two amplifiers.
Initially the difference between the two amplifiers was very obvious when heard thru the 3rd speaker, however after a couple of days of tweaking, Carver was successful in producing an amplifier that passed the null test, and the resulting amp was later mass produced as the Carver Magnetic Field M-1.5t amp.
Even the writers for Stereophile had to admit Carver's success. I also recall Carver claimed by using this same process he could replicate any high end amplifier being made at the time, including any tube amplifier.
It first seemed that this "experiment" might be an industry game changer, but apparently it was not? So the question is why not? Was it considered "unethical" to take a high end amp created from many hours of R&D, and simply duplicate the sound by trial and error? Or do audiophiles just like spending more money on their gear for bragging rights? So educate me.