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Old 26th June 2004, 10:08 AM   #1
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Join Date: Mar 2004
Location: Como
Default Modify Aleph 2 to run in class AB?

It's possible to modify the output stage of aleph 2 (or 5...) to run in ab class?

I won't ti use this amplifier in car but in class A the power consumption is to much!
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Old 26th June 2004, 11:07 AM   #2
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Join Date: Mar 2004
Location: Como
Not only the Aleph 2 ecc...

I'm interested of modify if one of Aleph 0,1,2,3,4,5...
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Old 26th June 2004, 12:08 PM   #3
uli is offline uli  Austria
diyAudio Member
Join Date: Dec 2002
Location: Vienna, Austria
Default theoretical formula

Related to Aleph 2 circuit diagram:

(R22/R40)*(R20/R21) = current gain factor of the CCS.

in case of Aleph 2 its 0.69.

Factor 0.5 -> pure classA

Factor 1 -> theoretical limit before oszillation.

Try 0.9 - 0.95 by changing R21 to ~510R without changing

anything else.

EXCEPT: R19 -> 18k - 22k. (influences idle current)

It is a good starting point: ~ 1A Bias, about 10A - 12A peak

As I said its theoretical, try at your own risk!



'Jazz is not dead, it just smells funny' F.Zappa
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Old 26th June 2004, 06:52 PM   #4
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Join Date: Mar 2001
An AB Aleph is not a pretty sight. It takes a lot of feedback
to make such a circuit low distortion in AB, and it pretty much
negates the point.
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