Robert, Thank You for fixing the UM10155 schematic to get the circuit to
amplify an input signal. So Raymond will know what was done I will
mention you eliminated C6 and C8 and corrected a wiring mistake. The
wire going from the emitter of Q12 to the anode of D3 was connected to
the wrong terminals in Raymond's schematic. The problem with C6 and
C8 seems unusual. Dave Allen version of the UM10155 power amplifier
includes C6 and C8 and he says his version works. This seems to imply
it makes a difference as to what type of transistors are used as
whether C6 and C8 are required.
Howard
Good morning,
The UM10155.asc file in the temp directory is the one I uploaded yesterday.
This is as per the datasheet except that I didn't follow the circuit
references exactly!
The models of BF824 and BF721 were posted in my reply to Helmut yesterday
... though for some reason I have them in my standard.bjt file.
I never downloaded Raymond's original circuit so C6 and C8 don't register
with me. The 100u 100n combination? Reservoir for the gate switching?
I was originally interested in the circuitry driving the output devices as
this gives a rapid discharge of the gate capacitance.
Regards
Dave
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