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This design has two issues to keep in mind:
1) It requires a regulated power supply for bias stability.
2) The bias voltage is subtracted from the output voltage swing.
😎
Popular Electronics October 1971
Popular Electronics May 1969
Transformer and two sit's that the way i like it.
Popular Electronics yeah !!!
Popular Electronics Magazine
Thanks Mr Pass
Kind regards
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yeah
I always knew that there is some interesting biasing scheme in Universal Tiger , which I can use for SIT
I always knew that there is some interesting biasing scheme in Universal Tiger , which I can use for SIT
Given the choice between 20 extra degrees of heat or 10 extra parts - more parts and less heat will win the day most of the time.
That sounds like an opinion to me. I'll take less parts, more heat and a little bit of musical magic.
That sounds like an opinion to me. I'll take less parts, more heat and a little bit of musical magic.
Me 2!! Couldn't agree more.
me thinks Pa's BA amp , or poor man's FW SIT-2 ( MR's iteration also)
with right speakers ......
with right speakers ......
Citation "This exclusive Pass Laboratories commemorative amplifier employs complementary matched pairs (2SK82 and 2SJ28) of Sony VFETs, which were in storage for nearly 40 years. " from avcat??????? SONY?PASS LABORATORIES?VFET??ClassA????????????????VFET?40?? ???
Is it true ? Are those VFETs sold by Acroman that old ?
Is it true ? Are those VFETs sold by Acroman that old ?
Yes, the Yamaha B-1 with 2SK77 came first - mid 70ties(?). And the Sony TA-N88 was one of the last, and using these 2SK82/2SJ28 complementary devices. I think that one with PWM output and it all, was a 1977/78/79 thing. I remember I read a review of a Sony TA-N7 ca 1980. That was the last time I can remember hearing about these devices. That is, until Nelson Pass came up with his SIT-1 and SIT-2. And the Digital do MaiN with 2SK77B.
I wonder, the American and European designers must have wanted to try these devices in the late 70ties(?).
I am not sure about the sound quality of these old Japanese VFET amplifiers. Probably no match for a Threshold 400A of the day! And remember, the VFET era was not long. Hitachi soon rolled out their HMA9500 amplifier, and Borbely designed the MOSFET Hafler DH-200. I think the pros of the VFET was overshadowed by Japanese designers still not knowing their Otala, and American and European designers did.
Well, let's us have fun with our vintage super-silicon now, and not dwell to much with amplifier history.
I wonder, the American and European designers must have wanted to try these devices in the late 70ties(?).
I am not sure about the sound quality of these old Japanese VFET amplifiers. Probably no match for a Threshold 400A of the day! And remember, the VFET era was not long. Hitachi soon rolled out their HMA9500 amplifier, and Borbely designed the MOSFET Hafler DH-200. I think the pros of the VFET was overshadowed by Japanese designers still not knowing their Otala, and American and European designers did.
Well, let's us have fun with our vintage super-silicon now, and not dwell to much with amplifier history.
Very interesting, thanks !
Here are links to the arcticles that describe the schematic posted by Nelson.
Very interesting reading, and confirming what ZenMod figured out some posts earlier than me: interesting bias and protection circuit.
I also like the input stage..maybe with some 2sk170/2sj74's.
Radio Electronics March 1973
Radio Electronics April 1973
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Good news tonite.
Worked on the DIY Sony SIT Amp article (part 1) all day today. Maybe finish
tomorrow. Needs one pair 2SK82/2SJ28 per channel.
Time to get your parts from circuitdiy.com.
(Actually at last count they still have lots of pairs, but don't wait too long)
Worked on the DIY Sony SIT Amp article (part 1) all day today. Maybe finish
tomorrow. Needs one pair 2SK82/2SJ28 per channel.
Time to get your parts from circuitdiy.com.
(Actually at last count they still have lots of pairs, but don't wait too long)