Weseixas, We did a few Stereophile shows but none of them were in '94. There may have been someone there using one of our amps though.
These days at home I use a speaker that is 16 ohms and goes to 20Hz. It uses field coil drivers with beryllium domes for the midrange drivers. There are no breakup in the speakers anywhere in the audio band, so they are quite smooth, very detailed and fast, owing to the fact that there is no magnetic sag in the magnetic field of the magnets- not unlike the way ESLs work. Clearly in its own way it expresses state of the art operation, even though it is not a low impedance planar or the like.
There are not a lot of published specs of our amps that are the result of independent measurement. One of the bigger problems we have run into is the fact that output of the amplifier floats, and so if the scope or analyzer used on the amp has a ground connection into the AC wall power, the result is that one of the speaker terminals will be at ground. This causes the amplifier to have high distortion and low power due to the resulting unequal drive of the power tubes in this condition. This was a problem with the Soundstage.com tests done about 10 years ago. In that test the amp only made about 100 watts- not the 140 that it did when we got the amp back from them and double-checked the results.
About nine years before that, an engineer in Salt Lake City sent us the results of a test that he did on one of our early MA-2s. That amp had a feedback switch that allowed that amp to run 8 db of feedback. The output impedance that resulted was under 0.5ohms. You can make a voltage source out of an OTL IOW, but to my ears it never sounded right when you engaged the feedback. I did notice that there were certain speakers that needed the feedback, but I found that if the speaker needed it- there was no way it would sound as good compared to a speaker that did not need the feedback.
That precipitated the investigation into the why of that matter, but I really did not feel comfortable in explaining the results of that investigation until about 5 years ago.
These days at home I use a speaker that is 16 ohms and goes to 20Hz. It uses field coil drivers with beryllium domes for the midrange drivers. There are no breakup in the speakers anywhere in the audio band, so they are quite smooth, very detailed and fast, owing to the fact that there is no magnetic sag in the magnetic field of the magnets- not unlike the way ESLs work. Clearly in its own way it expresses state of the art operation, even though it is not a low impedance planar or the like.
There are not a lot of published specs of our amps that are the result of independent measurement. One of the bigger problems we have run into is the fact that output of the amplifier floats, and so if the scope or analyzer used on the amp has a ground connection into the AC wall power, the result is that one of the speaker terminals will be at ground. This causes the amplifier to have high distortion and low power due to the resulting unequal drive of the power tubes in this condition. This was a problem with the Soundstage.com tests done about 10 years ago. In that test the amp only made about 100 watts- not the 140 that it did when we got the amp back from them and double-checked the results.
About nine years before that, an engineer in Salt Lake City sent us the results of a test that he did on one of our early MA-2s. That amp had a feedback switch that allowed that amp to run 8 db of feedback. The output impedance that resulted was under 0.5ohms. You can make a voltage source out of an OTL IOW, but to my ears it never sounded right when you engaged the feedback. I did notice that there were certain speakers that needed the feedback, but I found that if the speaker needed it- there was no way it would sound as good compared to a speaker that did not need the feedback.
That precipitated the investigation into the why of that matter, but I really did not feel comfortable in explaining the results of that investigation until about 5 years ago.