I know this discussion is about current production SIT, but I had a Sony TA 5650 VFET amp in the day for ten years before it failed and was very fond of it. SIT and VFET are different designations for the same kind of voltage controlled transistor type.
I have had a variety of tube amps, both push pull and SET and own several SET amps at the moment and three DHT based preamps.
I recently acquired one of the Sony TA 4650 VFET amps to use as a phono amp in a second location.
The phono amp uses a small signal VFET in the RIAA gain circuit, which then goes to a single small signal FET gain stage, and then feeds the push pull amplifier stage in this model. One can switch in or out the tone control stage which adds another small signal FET stage.
My thoughts about the VFET on hearing it again is that it most definitely is superior to most standard solid state amps.
The sound is very "fast" with the ability to image with enormous specificity in the sound stage in three dimensions.
The tonality is natural, with a non fatiguing character, unlike most transistor devices. The VFET has an analog sounding pulse response.
The dynamics are open and liquid, like DHT tubes.
Where it differs is that it does not quite have the "charm" factor of good DHT designs, and the tonal decay is sharper, without the more sumptuous resonant tails that SET designs have. The tonality of the VFET device is natural but a bit on the shallow side compared to tubes.
I have found that coupling DHT preamps with good solid state amps is an outstanding combination for some reason. I would not have thought that DHT preamp would synergies well with solid state amps, but they do, and sound very good that way.
Haven't tried the DHT preamps with the VFET yet, they are at different locations, but may get another VFET to try with Manley 300b preamp*.
I have had a variety of tube amps, both push pull and SET and own several SET amps at the moment and three DHT based preamps.
I recently acquired one of the Sony TA 4650 VFET amps to use as a phono amp in a second location.
The phono amp uses a small signal VFET in the RIAA gain circuit, which then goes to a single small signal FET gain stage, and then feeds the push pull amplifier stage in this model. One can switch in or out the tone control stage which adds another small signal FET stage.
My thoughts about the VFET on hearing it again is that it most definitely is superior to most standard solid state amps.
The sound is very "fast" with the ability to image with enormous specificity in the sound stage in three dimensions.
The tonality is natural, with a non fatiguing character, unlike most transistor devices. The VFET has an analog sounding pulse response.
The dynamics are open and liquid, like DHT tubes.
Where it differs is that it does not quite have the "charm" factor of good DHT designs, and the tonal decay is sharper, without the more sumptuous resonant tails that SET designs have. The tonality of the VFET device is natural but a bit on the shallow side compared to tubes.
I have found that coupling DHT preamps with good solid state amps is an outstanding combination for some reason. I would not have thought that DHT preamp would synergies well with solid state amps, but they do, and sound very good that way.
Haven't tried the DHT preamps with the VFET yet, they are at different locations, but may get another VFET to try with Manley 300b preamp*.