Sorta strange that it has insulation around it that would reduce its coupling to the air temperature. Wouldn't you want the thermostat on one or both heatsinks?
I believe insulation is integral in part from factory , at least I've seen them like that
as I understand position - it hangs on air in case , not heatsink
I have two idiot Cats , liking to lay on Papa's Koan M2 even in mid of Summer ....... so, while sinks are hot , innards can become scorching hot
as I understand position - it hangs on air in case , not heatsink
I have two idiot Cats , liking to lay on Papa's Koan M2 even in mid of Summer ....... so, while sinks are hot , innards can become scorching hot
I have a guess as to why he used them:
The laterals have enough tranconductance to do job, have around 0R5 internal resistance, and have a positive temperature coefficient. All of these factors facilitate an amplifier with so few parts.
Yes of course.
I had the same idea 9 years ago for the exact same reason (but without positive feedback).
I prefer simple circuits (I also prefer low gain amps for my efficient speakers), lateral mosfets allow that. They also tend to give lower distortion per Siemen of transconductance. The only reason to want more is for the damping factor, I achieved it through paralleling a pair of devices with an appropriate amount of feedback.
Nelson is brainier so he did it with positive feedback.
Edit: One other thing that can be said for the laterals (at least mine), is they match extremely well, so for the DIYer they may even work out to be cheaper than IRFP240/9240
I had the same idea 9 years ago for the exact same reason (but without positive feedback).
I prefer simple circuits (I also prefer low gain amps for my efficient speakers), lateral mosfets allow that. They also tend to give lower distortion per Siemen of transconductance. The only reason to want more is for the damping factor, I achieved it through paralleling a pair of devices with an appropriate amount of feedback.
Nelson is brainier so he did it with positive feedback.
Edit: One other thing that can be said for the laterals (at least mine), is they match extremely well, so for the DIYer they may even work out to be cheaper than IRFP240/9240
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Yes the 8 I bought some time ago were fairly close in the curve tracer....
And thanks to Nelson for allowing this deep insight in his newest creature....!
And of course also to Srajan and comrades enjoying us at 6moons so often......!
And thanks to Nelson for allowing this deep insight in his newest creature....!
And of course also to Srajan and comrades enjoying us at 6moons so often......!
I know it was just an accidental slip of the tongue. (or fingers in this case.) 😀
Of course we know the cats are much more smarter than we are. 🙂
fact (by default) that they're smarter than me , is not changing fact that they're two funny idiots
fact (by default) that they're smarter than me , is not changing fact that they're two funny idiots
Bright enough to know that the amp case needs more damping! 😎
And they don't ride motorbikes...much too cold.
I have updated my schematic of post #218 using information gained from the 6Moons photos and everything simulates fairly well.
I estimate the open-loop gain of the jfet and output fet stages into an 8 Ohm load to be 42dB with all feedback removed. This was measured as the V(Out+,Out-)/V(gates,fbnode), where gates is the jget gate node, and fbnode is the wiper of potentiometer P3. With a closed-loop gain of 14dB that means that there is 28dB of negative feedback, which is a huge feedback factor. Perhaps I am incorrectly estimating the open-loop gain, but that gain factor is fairly consistent with the F5.
I estimate the open-loop gain of the jfet and output fet stages into an 8 Ohm load to be 42dB with all feedback removed. This was measured as the V(Out+,Out-)/V(gates,fbnode), where gates is the jget gate node, and fbnode is the wiper of potentiometer P3. With a closed-loop gain of 14dB that means that there is 28dB of negative feedback, which is a huge feedback factor. Perhaps I am incorrectly estimating the open-loop gain, but that gain factor is fairly consistent with the F5.
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Ihquam
What is the function of P1 & P2 pots ? , it serve for biasing of output LatFet`s pair ? , or ...?
What is the function of P1 & P2 pots ? , it serve for biasing of output LatFet`s pair ? , or ...?
Output FET bias adjustment, similar to the same pots in the F5, but without the additional resistor, thermistor, and current limiter circuit.
Ihquam
I guess than P3 serve for output AC balance adjustment ?
and additional question , if let`s say we supply that F7(#317) with +/- 24VDC ,and with OPS - Iq = 1A , what is the approximate values for P1 & P2 than ?
Edit , I think that now you are very close to original F7
I guess than P3 serve for output AC balance adjustment ?
and additional question , if let`s say we supply that F7(#317) with +/- 24VDC ,and with OPS - Iq = 1A , what is the approximate values for P1 & P2 than ?
Edit , I think that now you are very close to original F7
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That will depend on the Idss of the jfets, the jfet idle current with degeneration, and the output fet Vgs at 1A. It is a pretty easy calculation:
Rdrain_load = Vgs_1A/Ijfet