The terminology in this case is confusion as those are vertical mosfets.
From page 1 of https://www.firstwatt.com/wp-content/uploads/2024/01/art_sony_vfet_40yr.pdf :
"Examples of “VFETs” were produced by Sony and Yamaha forty years ago and appeared in power amplifiers produced from about 1975 through 1980(3). These amplifiers are now prized for their exceptional sound, the credit popularly going to the linearity of the VFETs(4). They were called VFETs at the time because they have a vertical (not lateral) structure. The subsequent invention and dominance of vertical MOSFETs (Metal Oxide Semiconductor Field Effect Transistor) made use of the term confusing, so now they are generally referred to as Static Induction Transistors (SIT), except perhaps as reference to these original parts."
From page 1 of https://www.firstwatt.com/wp-content/uploads/2024/01/art_sony_vfet_40yr.pdf :
"Examples of “VFETs” were produced by Sony and Yamaha forty years ago and appeared in power amplifiers produced from about 1975 through 1980(3). These amplifiers are now prized for their exceptional sound, the credit popularly going to the linearity of the VFETs(4). They were called VFETs at the time because they have a vertical (not lateral) structure. The subsequent invention and dominance of vertical MOSFETs (Metal Oxide Semiconductor Field Effect Transistor) made use of the term confusing, so now they are generally referred to as Static Induction Transistors (SIT), except perhaps as reference to these original parts."
Okay, so I'm focusing in on a Babelfish XA252 SIT as a project for down the road. First the F5M, then my P3, Iron Pumpkin
M2X, Babelfish XA252 SIT though those two could flip. In any case I am reading about them but want to be sure to have parts that are becoming harder to source. I am speaking with a vendor re. THF-51S, what other parts for the M2X and XA252 should I be looking for?
M2X, Babelfish XA252 SIT though those two could flip. In any case I am reading about them but want to be sure to have parts that are becoming harder to source. I am speaking with a vendor re. THF-51S, what other parts for the M2X and XA252 should I be looking for?
When you hang around these circles, all of those mentioned projects seem fun and exciting. Looking forward to it!
Whenever a client says, " Is that all I need?" I say, nothing about this has anything to do with need
As long as it's fun!
Brother that is no fun! Indulge me in the audiopholery… how do you like it? What does it do well? All subjective and completely understand that, its all entertainment as pa says!
@Toys4Boys same thing, how are you liking the aleph? Unless pat put a gag order on you
I enjoyed building a more custom version of the F5m. It is still the amp that I listen to on a daily basis as I contemplate my next build.
Post in thread 'Pass F5m'
https://www.diyaudio.com/community/threads/pass-f5m.406472/post-7638137
Post in thread 'Pass F5m'
https://www.diyaudio.com/community/threads/pass-f5m.406472/post-7638137
I did see that. I also have in my back pocket the motor run caps between the outputs and the speaker terminals for both the F6 and the F5M. Which ones do you normally use? As that is definitely something I want to try.
Well, to be fair I haven't really put it through its paces, nor have I swapped it out. Haven't felt any need to 
. I'm running it directly from my Bluesound Node, which is a perfectly lovely/versatile piece but not my main source. I'm almost finished with my SP14 and have been too lazy, enjoying, to take the pre out of my SuperNait.
Enough preamble, my impression is that it is a very well-balanced amp capable of an excellent soundstage, very good bass and it is extremely quiet, judging by turning it up and ear to speaker, very quiet. It has a lovely mid-range and top end all somewhat reminiscent of tubes. It doesn't seem to be the last word in transparency, 2nd order?, and my recollection of the ACA Mini is that it was many of the above but more transparent and yet it maintained a harmonically rich tone. This is really unfair cause I did use the Mini like this but after a while hooked it up to the Naim and spun some records.
So, until I pump a better signal through it all comments are subject to change at a whim.
. I'm running it directly from my Bluesound Node, which is a perfectly lovely/versatile piece but not my main source. I'm almost finished with my SP14 and have been too lazy, enjoying, to take the pre out of my SuperNait.Enough preamble, my impression is that it is a very well-balanced amp capable of an excellent soundstage, very good bass and it is extremely quiet, judging by turning it up and ear to speaker, very quiet. It has a lovely mid-range and top end all somewhat reminiscent of tubes. It doesn't seem to be the last word in transparency, 2nd order?, and my recollection of the ACA Mini is that it was many of the above but more transparent and yet it maintained a harmonically rich tone. This is really unfair cause I did use the Mini like this but after a while hooked it up to the Naim and spun some records.
So, until I pump a better signal through it all comments are subject to change at a whim.
Don't get me wrong, it is transparent, I'm just not sure that it is as transparent as the Mini. A Node feeding it being a limiting factor at best also has an additional downside as volume is turned down you throw away bits. As to how it sounds w/ less than ideal recordings, I have a lot of bootlegs, many soundboard but still, it sounds fine to very good. On good recordings its absolutely lovely! One that caused me to sit up and take notice was Keith Jarrett Koln. The sense of his fingers on the keys and their location floating in space, seeming to follow as he ran the keys
Interesting description.
Thanks for the details.
Looping in @birdbox to see if he has any more details than Wow!
Me likey Aleph J ZM Ed. amp a lot!
[Edit: I'm not good at turning my impressions into well thought out descriptive language. "It has hints of cherry, orange blossom, with undertones of earthiness. The finish is outstanding, like a fine chocolate bar that you want to just continue to savor."]
[Edit Part Deux: "I like it a lot"]
[Edit Finale': You should definitely build one.]
[Edit: I'm not good at turning my impressions into well thought out descriptive language. "It has hints of cherry, orange blossom, with undertones of earthiness. The finish is outstanding, like a fine chocolate bar that you want to just continue to savor."]
[Edit Part Deux: "I like it a lot"]
[Edit Finale': You should definitely build one.]
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The XA252 amp is a sweet amp. I think you will like it. Coming from the Aleph J, I think you notice the bass, detail and immediacy of it. Read the thread carefully and be diligent to hook it up properly with the amp and preamp turned off etc. Also, it takes a bit more skill to assemble than the Aleph J as there are more parts that are scrunched closer together. Not too hard though. The output mosfets do not need insulators which is pretty nice and you don't need any standoffs as the boards can simply be held by the output mosfets since they are so large.
If you are looking to repurpose your power supply and chassis, the F5M or M2X are great options. You should be able to swap new amplifier boards in, bias them and go to town. Honestly, that is a cheap way to play around with different designs.
Surgar = Aleph J, M2, F6, F5 = transparency and detail
I built the ACA Mini and think it is pretty sweet. I think the distortion characteristics are part of what gives it it's detailed sound. It punches above it's 5 watts that is for sure.
If you are looking to repurpose your power supply and chassis, the F5M or M2X are great options. You should be able to swap new amplifier boards in, bias them and go to town. Honestly, that is a cheap way to play around with different designs.
Surgar = Aleph J, M2, F6, F5 = transparency and detail
I built the ACA Mini and think it is pretty sweet. I think the distortion characteristics are part of what gives it it's detailed sound. It punches above it's 5 watts that is for sure.