http://www.diyaudio.com/forums/showthread.php?postid=944958#post944958
that is just a rough sketch;
mebbe you can comment something, wakoo/short/hugger
mugger....?
here or there
or everywhere
or even
nowhere
TIA ,as always......
that is just a rough sketch;
mebbe you can comment something, wakoo/short/hugger
mugger....?
here or there
or everywhere
or even
nowhere
TIA ,as always......
Re: Papa-seems that you already burn your free time here,so maybe you can take a peek at
You have to re-write,
"Dear Nelson, could you please review it and give me any advice?"
Muhahahahahahahah . . . . . . . . . .
choky said:[B
mebbe you can comment something, wakoo/short/hugger
mugger....?
...
[/B]
You have to re-write,
"Dear Nelson, could you please review it and give me any advice?"
Muhahahahahahahah . . . . . . . . . . 
It so happens that I built almost exactly the same circuit, although
I don't seem to have my curves here on the computer. I used
9240's and 240's, .47 ohm Source resistors, and pots to trim
the (1k) resistors instead of trimming between the JFETs. This
allows trimming of all parameters. Also, I did not degenerate
the Sources of the JFETs with the 22 ohm resistors.
It worked fine and sounded good. The performance will be very
bias dependent, and you will want to put as much bias on the
output stage as you can. I recall that I ran the outputs at
about 2A each, and I got about 100 watts out of it.
I don't seem to have my curves here on the computer. I used
9240's and 240's, .47 ohm Source resistors, and pots to trim
the (1k) resistors instead of trimming between the JFETs. This
allows trimming of all parameters. Also, I did not degenerate
the Sources of the JFETs with the 22 ohm resistors.
It worked fine and sounded good. The performance will be very
bias dependent, and you will want to put as much bias on the
output stage as you can. I recall that I ran the outputs at
about 2A each, and I got about 100 watts out of it.
Papa -if I may ask another one question....
what is your opinion/attitude about using diodes/zenner/led as level shifters in active stages?
example-if I need to use weeny jfet in place with higher voltage,and I can achieve that only with cascoding or I can use mentioned elements connected to source(s)......?
I saw that already somewhere on the net,but I'm interested what you'll say........
even if lack of this arrangement in your constructions is evident
what is your opinion/attitude about using diodes/zenner/led as level shifters in active stages?
example-if I need to use weeny jfet in place with higher voltage,and I can achieve that only with cascoding or I can use mentioned elements connected to source(s)......?
I saw that already somewhere on the net,but I'm interested what you'll say........
even if lack of this arrangement in your constructions is evident
jh6you said:
Still sleeping . . . ?
Are you sure your nut is healthy?
I meant what is the tech background of the resistors . . .
How they reduce the offset . . . ?
you were present in X thread from beginning.....as I saw ;
anyway....everything is there,and I anyway can not explain it better
this is really just on paper,or something more in my head.....
we will see........
OK. I went back to the old thread.
Learned the purpose of the resistors, reading Papa's comments:
¡°In any case, so we're clear, resistors from both outputs
can be fed to the node which attaches the two Sources
for the diff pair and the Drain of their current source.¡±
¡±Works quite well, as any absolute DC offset results
in opposing bias to the diff pair. This technique also
presumes a DC impedance to ground associated with
the input so that the feedback is not unity gain at DC.¡±
¡°The common-mode feedback to the diff pair sources for
reducing absolute DC offset works better than I would have
expected, but there it is. In conjunction with resistive
loading of the output, DC drift is well under control.¡±
¡°I have used as low as 5K without things going to hell.¡±
Choky, are you actually building this now?
Learned the purpose of the resistors, reading Papa's comments:
¡°In any case, so we're clear, resistors from both outputs
can be fed to the node which attaches the two Sources
for the diff pair and the Drain of their current source.¡±
¡±Works quite well, as any absolute DC offset results
in opposing bias to the diff pair. This technique also
presumes a DC impedance to ground associated with
the input so that the feedback is not unity gain at DC.¡±
¡°The common-mode feedback to the diff pair sources for
reducing absolute DC offset works better than I would have
expected, but there it is. In conjunction with resistive
loading of the output, DC drift is well under control.¡±
¡°I have used as low as 5K without things going to hell.¡±
Choky, are you actually building this now?
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