Vfet / SIT Amplifiers

Sony and Yamaha Vfet's are still my favorite amplifiers after all of these years. Trying to keep my B-2 running for the next generations! Just wondering if anyone has compared any other V-fet amps to the B-2x?

Well, both B-3s and the TA-N7 are fully restored, so I reckon they're in their prime. If I was to rate all V-FETs I've tested so far, it would be like this:

1. Sony TA-N7

2. 2x Yamaha B-3 in BTL

3. Yamaha B-2

4. Yamaha B-3

5. Victor JM-S7

6. Hitachi HA-500F

hi @fiesta75 the B-2X is a really nice amplifier indeed. I have compared in the sense that I do have a couple of B-2Xs amps and I am well aware of their sonic qualities but my units are not fully restored yet and it would be immature to state an opinion, one way or another, between my B-2Xs and the vfet units.

@kitr I have no doubt your units are in OK working condition. Full restoration with the specific key components addressed is a bit more than just a refresher and a recap.

As and example, the B-2 you compared to the 2XB3s and others, based on your video, that B-2 looked like it was no where near the state of back to prime (e.g original ill fated drivers and pre-drivers, original signal path routed via the original selector robbing you of details, etc). Comparing that B2 with anything else would only yield an opinion on the effective age of two different units and not how they would work in prime condition. This is particularly important is when you compare vintage units with modern gear.... it is important they have relatively close effective age so that the actual age can be ignored, rendered a non-factor. 

As far as properly restoring a TA-N7 or the B-3s, our definitions of proper restorations might vary. All I can tell you is that it is not as simple as replacing a bunch of parts and hoping it will sound OK. It is not about the bench tests either. It takes a good amount of time and research to make an already good sounding amp sound excellent. 

I have listen to all of those amps and very much any vfet amp ever made, and have done it numerous times, with different units in different conditions, with various degrees of restoration, etc.

Based on what I know today, I do not think I could come up with a similar pecking order, as that pecking order would have changed at least half dozen times over the years as I learned more about these units...their strengths and weaknesses, areas of improvement / that must be addressed, etc.

Then the rest of the other relevant factors would compound the problem even further..., such as the rest of the system components which could work with one amp but not the others (B2 and sissy preamps is an example that comes to mind...B-2 can sound awful with certain preamps..ask me how I know), the type of music, etc. 

Last but not list, the audio memory comes in play. We as human have a surprisingly short audio memory..so comparing something I heard a few months back with something I would be listening at today, it is no way a relevant comparison.

Now, those are things I learned based on my personal experience, based on my curiosity and depth of involvement with these vfet amps over the years which is extensive, yet it is not general by any means BUT, if I learned one thing for certain is that coming up with a specific pecking order would have to be done with the all the amps at the same listening session and with all other things being equal and even that might prove to be difficult.

For similar reasons I will never state who I think is the most beautiful woman in the world or which vfet amp sounds best ;)

Well I’ve an Absolute Audio Labs SIT-A15 SE power amp being built for me presently. Supposedly greater treble and bass extension than First Watt SIT3 and predominantly negative 2nd order harmonics which should give a more expansive sound stage than the SIT3 also, due to use of Tokin SIT’s. I’ll pair with a icOn 4PRO Unbalanced passive pre and Accurate Ultimate D1000 DAC. The pre has 3db gain and DAC very high output so it should be a favourable pairing. I believe this will be a significant upgrade over my Existing Pass Mini Aleph and 15W rather than 10W is nice also. ;)

mjw25a,

FW_SIT3 2nd harmonic is significantly dominant over the rest of the higher order harmonics. I do not believe that any more dominance of the 2nd would add any benefit. I have studied this quite a bit...on the bench with a proper audio analyzer and most importantly side by side comparison with other vfet amps.

I can't wait for your impressions of the new amp. Based on the few photos I see on the net it looks like a nice project and of good quality too. 

Please share your impressions.