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Old 9th August 2020, 07:00 AM   #61
EUVL is offline EUVL  Europe
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SJEP120R100
Ciss — 670pF
Coss — 103pF
Crss — 97pF

6x 2SK1058 parallel
Ciss — 3600pF
Coss — 2100pF
Crss — 60pF

But then if you have no Semisouth, maybe 6x matched 2SK1058 plus a Cascode is worth considering.


Good idea,
Patrick
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Old 9th August 2020, 08:32 AM   #62
petoluk is offline petoluk  Czech Republic
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Weeell, but the SJEP data sheet gives the capacitances at Vds = 100V / Vgs = 0V, while 2SK1058 is quoted at Vds = 10V / Vgs = -5V. If you correlate the data based on the charts (at least for Ciss, there's no Coss / Crss chart in the 2SK1058 data sheet), you get:

SJEP120R100
Ciss = ~850pF

2SK1058
Ciss = ~330pF x 6 = 1,980 pF

Still a lot, but not 5.5x as much, "only" 2.5x. So perhaps 4 in parallel selected for the highest yfs would just about cut the mustard... (2SK286, with 1.4 typ / 2.5 max yfs and Ciss of ~400pF, could still be a cheaper / easier to find option.)
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Old 9th August 2020, 10:00 AM   #63
claudio52 is offline claudio52  Italy
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Can this silicon carbide power mosfet be a candidate?
https://www.mouser.it/datasheet/2/90...0d-1795432.pdf
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Old 9th August 2020, 10:19 AM   #64
petoluk is offline petoluk  Czech Republic
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P.S. Found the capacitance charts for the 2SK1058 in TO-3, née 2SK135, so at comparable Vds / Vgs (10V / 0V), we'd get:

SJEP120R100
Ciss = ~850pF
Coss = ~300pF
Crss = ~300pF

2SK1058
Ciss = ~330pF
Coss = ~310pF
Crss = ~10pF
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Old 24th August 2020, 07:53 PM   #65
Antoinel is offline Antoinel  United States
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F8 is innovative, an example of unmatched simplicity and efficiency-performance.

Let's broaden the view of this innovation by considering a classical power amp which has the familiar 3 stages. An input diff amp, followed by the last voltage amp and followed by complementary buffers. Let's do unto this classical amp what Mr. Pass did to J2.

Disable one semi from the the input diff amp, and return loop feedback to the source or emitter of the remaining semi in diff amp. Maybe easier written than done; but its an experiment!

Best
Anton
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Old 24th August 2020, 08:18 PM   #66
Zen Mod is online now Zen Mod  Serbia
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heavyhearted, I must admit - F8 is equal to (my beloved) M2 in sheer wit and elegance, and that even without Iron in signal path

go figure ........... nothing to Babelfish there


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Old 24th August 2020, 08:27 PM   #67
Nelson Pass is offline Nelson Pass  United States
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Don't feel bad. Initial front end to Last Sony Vfet Amp is M2 front end w/ Edcor.

Just for you....
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Old 24th August 2020, 09:03 PM   #68
Zen Mod is online now Zen Mod  Serbia
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Quote:
Originally Posted by Nelson Pass View Post
Don't feel bad. Initial front end to Last Sony Vfet Amp is M2 front end w/ Edcor.

Just for you....
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Old 25th August 2020, 06:44 AM   #69
2 picoDumbs is online now 2 picoDumbs  Australia
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Quote:
Originally Posted by Nelson Pass View Post
Don't feel bad. Initial front end to Last Sony Vfet Amp is M2 front end w/ Edcor.

Just for you....
Nice one.
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