OK, I got my TungSol RI 6SN7s. Visually, there was little difference. Eveything you can see looks identical except for the color of the plates. The EH have gray plates, the TS have black. I put 5 in one AtmaSphere MA1, and left the Electro Harmonix tubes in the other (I actually took them out and put them back in, in case that would make a difference, maybe by cleaning corosion off the contacts). I let the TSs bun in fo about 25 hours. I ran the outputs of my Wadia GNSC 850 to a Pass X1 preamp, which I set to mono. I then disconnected both speaker wires, and pulled them to one side so they were coming from the same spot, and I could not tell which was which. I labelled one A and the other B. I put one Talon Hawk with stand in the middle of the living room and did a blind test of the amplifiers with different tubes. I concluded the one with the Tung Sols sounded noticably better than the one with the EH tubes. The TSs sounded richer in the lows, more 3 dimensional, and more liquid. By comparison, the EHs sounded a bit metallic and flat. The difference was not huge; it was not like the change you get from changing a major component like an amplifier or CD player. The basic characte of the amplifers was the same, but one was a better version than the other. Unlike many comnponent changes, there seemed to be no tradeoff; I didnt' hear anything get worse going from the EH to the TS. The only question in my mind still is whether the difference was due to the design of the tube themselves, orr the aging of the EH tubes. The EH are about 1.5 years old, and have about 1200 hours on them (I estimate). I suppose I should buy a set of new EH to come to some real conclusions. I'll think about it.
