DIY SONY VFETS pt 3 - Got VFETs?

[guyome]

New boards can be optimized for 2sk82 2sj28 with change of two resistor values.

Any hope for the 2sj20 from NEC ?

Thanks !

 

[Nelson Pass]

If it comes in TO3 then I think so. I don't have data on it.

 

[Zen Mod]

I have only this

 

[Zen Mod]

found this too

most likely collected from forum

 

[Flikoman]

I have two matched pairs J18 and K60 from Sony. Maybe I will put them to good use

 

[HelmutHolz]

What about Yamaha 2SJ26 / 2SK76? They come in TO3 and the data is well known. I tried them and they sound promissing, but I don't know the best operation values.

 

[Soundhappy]

Does for this Part3 batch Diyers need CCS mosfets.. if yes.. what the reference is IRF250 etc. ??

Best regards

 

[Zen Mod]

post @17

https://www.diyaudio.com/community/threads/v-fet-sit-data-sheets.369005/post-6566014

 

[TungstenAudio]

Thanks for that link, been trying to remember where all those datasheets were.

 

[HelmutHolz]

Many thanks, I know this thread quite well, but I am not smart enough to find the sweet spot. May be I have to learn how to handle some mearurement
équipement. My drawers show some pairs of this Yamaha goodies, I am curious, but I fear a little bit, the sound will be identic to those Sony parts, so nothing new

 

[Zen Mod]

at first glance, Ugs range is lower comparing to Sonys, so that would need (trivial) rearrangement of biasing voltage divider

regarding sweet spot, I know Pa would answer ditto, but I didn't spent any time looking at graphs of Sony, neither got them on bench for measurement

even if I have some (both weaker and stronger ones) in boxes

 

[Nelson Pass]

I expect anything with a reasonable dissipation figure to work with minor adjustment.

It is, after all, just a follower.

 

[Zen Mod]

Papa has spoken. It is so.

 

[Soundhappy]

Does for this Part3 batch Diyers need CCS mosfets.. if yes.. what the reference is IRF250 etc. ??

Best regards

I mean for Diyers with 2SJ28 and 2SK82 who want build Part 1 and 2 versions
could be possible buy in the store the kit with pcb's ,aluminium brackets, FE transformers
and mosfets TO-3 IRF250 ?

 

[Nelson Pass]

I have not made a front end or PS filters for this, considering that there are
some available on the site, but if needed I can do so.

 

[guyome]

Thank you for your quick answer Mr Pass

I bought 4 2sj20 from jimsaudio

 

[martyh]

Will the front end and filters from diy vfet part 2 work with these boards? Any plans to make the part two front ends and filters available in the store?

 

[cjfrbw]

Great. I gots the 60/18 VFETs and the front end driver boards. Will get them into 4650 chassis for nostalgia if I can manage it. So, next, do the front end boards and set up test rig for my VFETs (they all pass the diode test).

 

[Nelson Pass]

Will the front end and filters from diy vfet part 2 work with these boards? Any plans to make the part two front ends and filters available in the store?

Yes, it's a similar situation, but the current sources are not constant - different vfets like different loads, and the 2sj18 and 2sk60 are more optimal into 16 vs the 8 Ohms of the 2sk28 and 2sk82.

 

[martyh]

Thank you. looking forward to the writeup.