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Old 5th November 2012, 05:24 PM   #41
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Because... A Darlington would be interesting to try - it's been in the back of my mind. I'd want to try a simulation first.
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Old 5th November 2012, 06:39 PM   #42
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Because... A Darlington would be interesting to try - it's been in the back of my mind. I'd want to try a simulation first.
Thank you wrenchone. Please do a simulation; it'll be mighty interesting. I'll send a hypothetical schematic; my humble contribution. best regards.
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Old 5th November 2012, 06:57 PM   #43
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Thank you wrenchone. Please do a simulation; it'll be mighty interesting. I'll send a hypothetical schematic; my humble contribution. best regards.
Please ignore schemo. It is flawed. I'll clean up.
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File Type: pdf TriodishBJT.pdf (29.7 KB, 69 views)

Last edited by Antoinel; 5th November 2012 at 07:08 PM.
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Old 5th November 2012, 07:06 PM   #44
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at least one important resistor is missing
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Old 5th November 2012, 07:10 PM   #45
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at least one important resistor is missing
Thank you Zen Mod. I'll clean up first the schematic above. It is not right.
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Old 5th November 2012, 07:40 PM   #46
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Attached is a sim - food for thought. At the excitation level shown, THD is about 0.08%, mostly 2nd and 3rd Order. Gain is ~8X. You need a small negative supply to properly bias things, but so did the original SIT circuit.
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Old 5th November 2012, 08:00 PM   #47
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Attached is a sim - food for thought. At the excitation level shown, THD is about 0.08%, mostly 2nd and 3rd Order. Gain is ~8X. You need a small negative supply to properly bias things, but so did the original SIT circuit.
Thank you wrenchone. You are way ahead of me. Will it demonstrate the classical triode characteristic curves? Your schemo is worthy of prototyping. Will it sound like a triode amp?

My "too late" schematic is attached for completeness. My apology for naming each bjt and simultaneously showing its emitter arrow. Best regards.
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File Type: pdf TriodishBJT.pdf (39.9 KB, 56 views)
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Old 5th November 2012, 08:59 PM   #48
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The Darlington should have a pentode-like characteristic (current-driven rather than voltage driven), but with more tilt than the mosfet solution. The Schade-connected implemenntation with buffer will still have triode-like characteristics.
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Old 5th November 2012, 11:00 PM   #49
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The Darlington should have a pentode-like characteristic (current-driven rather than voltage driven), but with more tilt than the mosfet solution. The Schade-connected implemenntation with buffer will still have triode-like characteristics.
wrenchone: You have expanded the range of Schade Feedback in the preceeding posts to inclute the forgotten bjts. I hope that this approach continues to be new, unprecedented and practical. Triode-like sound which is mediated by bjts may become a common occurence in our diy world.
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Old 9th November 2012, 03:47 AM   #50
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I'm working on a switching voltage/current regulator to fix a fuse -blowing problem with L'Fake Lite that happens when I snap on AC power. I noticed the problem the afternoon befor the latest Burning Amp, and brought the amp configured as L'Fake rather than L'Fake Lite as a result. L'Fake powers up in the living room with no problems, as it has a current source rather than a paralleled light bulb load.

The solution I mention will rguale from a higher DC supply to a lower and limit the startup current. More details will emerge when I get to complete and test the thing...
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