Update on Pa's new F5?

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The new ACA mini is based on the F5.
 

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Official Court Jester
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......

Because Pa is seldom present at Batsch, ZM goes wild all the year day and night!

:yes::yes::yes:

ha!

here it is - unnecessary complicated (so- Babelfish) F5

sole one trimpot for Iq and that's it

though - input JFet pair needs special matching attention :bawling:

have it filed few years already ..... and it'll stay that way
 

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Official Court Jester
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I wrote that before - minute changes of input JFet Idss or, in other words - if we include their source trimpot - minute changes of its position, are making dramatic changes in THD and THD Spectra

so, no way of Damn Greenhorn! making it, without first obtaining some hardware and learning how to use it, for setting THD Spectra of an amp

it seems Papa spoiled even me , of lately, tending to make more and more simpler Babelfishes

:rofl:

(No way, Jose! ZM is Omnicomplicator)
 
ZM: That makes sense:
The source trimpot in the original F5 modified the open-loop gain balance between the upper and lower halves.
Your Babelfish F5 eliminates degeneration of the output FETs and greatly increases the open-loop gain, thus magnifying the effect of the source trimpot.

This problem probably goes away if the F5 style feedback is replaced by one simple voltage divider to the JFET source pins, with or without the trimpot. But, then the amplifier is no longer has the unique characteristic of the F5.

Yes, with the Babelfish F5 emitter followers driving the gates of the output FETs, hocky puck input capacitances should be easy to drive.