Now that the dust has settled on the DIY Sony VFET project, parts 1 and 2
we come to the design which accommodates the 2SJ18 and 2SK60 parts
which you may recall are the 1 die versions of the 2SJ28 and 2SK82 (which
have two of the same devices in parallel in the TO-3 package).
This design is for those transistors, and also for some other variations we might
want to play with, and like the parts 1 and 2 come in the flavor of the N or P
channel parts.
I have tested prototypes and purchased the pc boards and mounting brackets
for 300 channels, (150 of each polarity) and kits will be offered in the store soon.
This kit assumes that you have some of these Sony parts, whether hoarded for
years or freshly scraped out of an old receiver.
Also there are plans for versions using other fets in plastic TO-247 packages
for the store's UMS mounting pattern.
More information and documentation to follow shortly.

we come to the design which accommodates the 2SJ18 and 2SK60 parts
which you may recall are the 1 die versions of the 2SJ28 and 2SK82 (which
have two of the same devices in parallel in the TO-3 package).
This design is for those transistors, and also for some other variations we might
want to play with, and like the parts 1 and 2 come in the flavor of the N or P
channel parts.
I have tested prototypes and purchased the pc boards and mounting brackets
for 300 channels, (150 of each polarity) and kits will be offered in the store soon.
This kit assumes that you have some of these Sony parts, whether hoarded for
years or freshly scraped out of an old receiver.
Also there are plans for versions using other fets in plastic TO-247 packages
for the store's UMS mounting pattern.
More information and documentation to follow shortly.

Been waiting for ya Poppa. 🙂 I have both actually. 😛 I sent everything I have off to a friend who can do proper testing to make sure they are all real and what they are... sometimes you have real, but mislabeled, I know you ran into that before.
JT
JT
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This could be a fun way to use a pair of Semisouth parts 😀…
Also there are plans for versions using other fets in plastic TO-247 packages
for the store's UMS mounting pattern.
…
I have a few spare from recent TA-5650 rebuilds, so looking forward to this.
Which is going to be the better option, N-Type or P-Type?
Which is going to be the better option, N-Type or P-Type?
Yes! I would love to know if Nelson thinks this is possible since I have a stash now.This could be a fun way to use a pair of Semisouth parts 😀
Best,
Anand.
A big welcome.
Hope the store also will sell/give a link for the beautifully designed cases…
Jason, I cross my fingers, so much it is sore.
Hope the store also will sell/give a link for the beautifully designed cases…
Jason, I cross my fingers, so much it is sore.
As with the first series they are pretty similar. Biggest difference is these vfets are biased by current sources which roughly double the appearance of the load impedance. As the optimal impedance for the 2sk82 and 2sj28 was roughly 8 Ohms, the 2sj18 and 2sk60 are more like 16, this because the former has 2 of the die in parallel. So in the case of the 2sj18 we use a mu follower to make the vfet think the load is 16 ohms, and a variation of that for the 2sk60.I have a few spare from recent TA-5650 rebuilds, so looking forward to this.
Which is going to be the better option, N-Type or P-Type?
This is great news! I hope that I am able to buy one. I (very nobly) did not enter the lottery because I have the 2sk82 and 2sj28 VFETs. Now the time has come. Really looking forward to building the amp into that gorgeous chassis. Just hope I am not too late to the store.
Question: could we modify the CCS that you mention above, Nelson, for the 2sk82 or 2sj28? I want to build the pt.1 or pt.2 version. Thanks!
Question: could we modify the CCS that you mention above, Nelson, for the 2sk82 or 2sj28? I want to build the pt.1 or pt.2 version. Thanks!
I have the 2SJ28 - can I use it in the new offer of boards? With a modulated source of course?
If correct, I understand my pair of 2SK180 needs to stay in the drawer then, talk being only about a solution for SITs in TO-3 packages (and some TO-247 flat packs).
If correct, I understand my pair of 2SK180 needs to stay in the drawer then, talk being only about a solution for SITs in TO-3 packages (and some TO-247 flat packs).
Did the DIY Audio round 3 “VFET-less” kits die on the vine?
I, too, passed on the lotteries since I already had VFETs.
Keeping my various VFETs and SITs tightly grasped…
I, too, passed on the lotteries since I already had VFETs.
Keeping my various VFETs and SITs tightly grasped…
Perhaps I am confused, and very ignorant. He mentioned VFETs other than 2SJ28, and 2SK82s, that I am hoarding. Perhaps it will accommodate either, with other component value changes.
Yes, that would be perfect.Perhaps I am confused, and very ignorant. He mentioned VFETs other than 2SJ28, and 2SK82s, that I am hoarding. Perhaps it will accommodate either, with other component value changes.
Grredy boyz at work

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