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Old 25th April 2008, 06:48 PM   #21
maxpou is offline maxpou  Canada
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And now at 100Khz
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Old 25th April 2008, 08:07 PM   #22
peufeu is offline peufeu  France
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Tiny bit of overshoot but otherwise looks good.
And the sound ?

Anyway, inserting a 100R in the output is always a smart move, just in case you get a short at the output (easy with RCAs), to avoid smoking the JFETs... it will also protect against oscillations.

If you use it to drive headphones (but the JFETs seem a bit wimpy for that) you must add a resistor since headphone jacks short for a brief time on connection.
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Old 25th April 2008, 10:37 PM   #23
maxpou is offline maxpou  Canada
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Hi Peufeu,
i don't know how it sound because i take all mesurement on my breadboard. thank you Maxpou
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Old 25th April 2008, 11:08 PM   #24
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Hi maxpou,

Pulse response looks good, no ringing at all, try some small compensation capacitor over local feedback resistors to take care of overshoot.
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Old 26th April 2008, 09:30 AM   #25
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Hi Maxou,
You could as well try without the output followers. The overshoot will most probably vanish, the stability (into capacitive loads) is amazing. I would probe the output while it is connected to the following amp and check the sound both with complimentary output follower and without.
Nice work, keep it going!
Rüdiger
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Old 28th April 2008, 06:24 PM   #26
maxpou is offline maxpou  Canada
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Hi Guys,
here the pic without the output stage with 3.9K//300pf. thank you! Maxpou
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Old 28th April 2008, 06:50 PM   #27
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At what freq?

Rüdiger

Edit:
if it's 10kHz, it's not good. I have a very simple version of this with 170/74 in the front and BC550/BC560 as VAS, set for 6dB of gain, and the square is fine up to several tens of khz!

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Old 28th April 2008, 09:30 PM   #28
maxpou is offline maxpou  Canada
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Hi Rüdiger,
sorry i forgot the frequency: 100Khz. Thank you! Maxpou
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Old 30th May 2008, 09:08 PM   #29
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Hi Maxpou,
you could swap the bases of Q14 and Q18 to the corresponding FET drains. increases (ol-) gain and decreases distortion.
Rüdiger
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Old 30th May 2008, 10:14 PM   #30
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Quote:
Originally posted by maxpou
...

Hi Maxpou,
in my opinion
please f*** 2nd, 3rd, 4th harmonics
but beware of this 15kHz peak!
Better use OLG,
true
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