Tried the 2SB649 (with 2SD669 current source) in my simulation, and that was very slightly worse than the MJE340/350. Also tried ZTX458/558 which was very good indeed.
A related issue is the decision on whether to use a current source VAS load, or a bootstrap as in the P101 circuit? I've tried both in my simulations, and haven't seen any difference in distortion.
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When I looked those up in Digi-Key it said “Tariff eligible”. Not that I’m against paying a tax, but I wonder if Made In China Toshiba is as good as Made In Japan Toshiba.
Made in Korea Fairchild seems to be decent stuff, but it has been that way for some time.
Made in China Toshiba power transistors are available in the form of TTC5200/1943, allegedly equivalent to the original 2SC5200/A1943. They were found to have a die that was 30% smaller but still rated the same as the Japanese parts which were soon discontinued, replaced by TO3P versions 2SC5200N/A1943N about 6 years ago. I'm not sure what goes on there because the original Japanese part numbers with a T0264 package are now back in the catalog too. That's 3 versions to choose from.
Anyways, the Chinese parts seem to perform OK within ratings. I haven't done any serious testing to find fault other than load testing a few amplifiers to just beyond full rated power after repair and replacements. Nothing has failed yet under those conditions.
Anyways, the Chinese parts seem to perform OK within ratings. I haven't done any serious testing to find fault other than load testing a few amplifiers to just beyond full rated power after repair and replacements. Nothing has failed yet under those conditions.
I use KSC/KSA parts in my amplifier. Now I have 100-100 of TTC/TTA004B to try. I'm interesting how they will work in practice. Hfe looks very consistent within a same polarity, but found pairs is not as easy...
Sajti
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