Vfet / SIT Amplifiers

Pass Labs SIT amps are very appealing.
@ericteh  thanks for posting your impressions! 

The warm and full sound seem to be consistent across most vfet amps and the resemblance to the "tube sound" is not by coincidence since the SIT I-V curve characteristics are similar to those of a triode.

I cherish my vintage SIT amplifiers and C-1, the only Vfet preamplifier, and put them through rotation in my listening space. I have most of the SIT amps ever made by the five Japanese manufactures from Japan (except the newer B-1a from Digital Do Main)

One of these days I will look to build a Pass design SIT amplifier, as I have a few transistors that can be put to better use than to rest comfortably in my storage bins.

The list of my curent SIT Amps collection:

Yamaha B1, B2, B3 (C1 preamp)

Sony TA-N7, TA-N8550, TA-5650

Victor (JVC) JM-S7

Sansui BA-1000

Lo-D (Hitachi) HA-500F

@ericteh ,

I now have a First Watt SIT-3 in my room right next to the other Vfet amps :)
I concur that it has great finesse and yes, it is a low gain amplifier.
The low gain is not a problem if you ran the SIT-3 with the proper preamp and efficient speakers.
I have the SIT-3 hooked up to a Yamaha C-1 that can push out like 3v, For speakers I am using Yamaha NS-2000 that are 90dB+ .
The all vfet sound of the preamp and the amp is addictive. An excellent match for the Beryllium drivers of the NS-2k..

I recently acquired a First Watt SIT-3 and I like my F2-J much better. I know I am in the minority in not loving the SIT-3.

It may be that the SIT-3 doesn’t like the impedance swings of my particular speakers.  Not saying it’s not a good amp, just not good synergy in my system.

In my system, the SIT-3 sounds like a computer simulation of an SET amp.

Yes, SIT-3 likes linear and higher efficiency speakers. More important is what you use to drive it with, since SIT-3 has relatively low gain.
There is lot of synergy between the SIT-3 and the Yamaha C-1 I drive it with. 

It sounds sublime in my setup and fits well with the pack of classic Vfet amps.

I have a FW SIT-3 amp, which I really like. It has plenty of power for my Horning Eufrodite Elipse Speakers. They have 98db efficency with a 4 ohm flat load, which is in the SIT-3 sweet zone.
The sound is detailed, smooth, airy, with beautiful tonal colors and has no electronic signature whatsoever.
I also run 300b mono's, which have a little more texture but, the FW comes very close.
It will be a classic in years to come!