even more lateral fets

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ed
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#76 Re: even more lateral fets

Post by ed »

post deleted...I now understand the previous post...

t means transistor!
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Mike H
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#77 Re: even more lateral fets

Post by Mike H »

Is it this capacitor that you were referring to. If so, do you think I can just move it from the output of the buffer to the output of the opamp
Yes, that is what I meant.

:thumbleft:

Re current drive to the MOSFET, you can put the ammeter probe over the MOSFET gate pin (or the 220R) and see what the gate current is with a 10 kHz squarewave. I'm guessing the gate cap could be 1,000 pF or more, would be interesting to see what it shows.
 
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#78 Re: even more lateral fets

Post by ed »

last installment, I hope...
mofo5 cct.jpg
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mofo5 pcb.jpg
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#79 Re: even more lateral fets

Post by Mike H »

Looks fab, have you done a frequency response plot?
 
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#80 Re: even more lateral fets

Post by ed »

mmmm...
mofo5 fr.jpg
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#81 Re: even more lateral fets

Post by ed »

and here is the original mofo...
I seem to have lost the plot
mofo1 fr.jpg
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#82 Re: even more lateral fets

Post by Mike H »

OK, looks flat in the right places. :thumbleft:
 
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#83 Re: even more lateral fets

Post by IslandPink »

Does the top-end sound a bit duff, Ed ?
It doesn't look like much , but I know from the current-sourced filament supply project a few years ago with Nick and Andrew that small phase rotations up there can make or break the sound.
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#84 Re: even more lateral fets

Post by Nick »

IslandPink wrote: Mon May 22, 2023 12:01 am Does the top-end sound a bit duff, Ed ?
It doesn't look like much , but I know from the current-sourced filament supply project a few years ago with Nick and Andrew that small phase rotations up there can make or break the sound.
Though I am not sure how we can know that that effect in a heater supply will have the same effect in a power amp (or for matter we also don't know it wont). But we do know that loads of folk are more than happy with output transformers that are more than 0.1dB down at 20k.
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