Sorry if this has been covered elsewhere but I did try and I couldn't find it.
I'm just finishing assembly of my Aleph 5 clone monoblocks and all appears to work fine on the bench.
Two questions, what level of DC offset is typical or acceptable on the output and ho can I adjust it if it's wrong?
Secondly I have read Nelson saying that Aleph 5's work better with higher bias curent. Assuming I have the thermal capacity in the sinks how can I adjust the bias up?
I'm just finishing assembly of my Aleph 5 clone monoblocks and all appears to work fine on the bench.
Two questions, what level of DC offset is typical or acceptable on the output and ho can I adjust it if it's wrong?
Secondly I have read Nelson saying that Aleph 5's work better with higher bias curent. Assuming I have the thermal capacity in the sinks how can I adjust the bias up?
Did you really search. I asked because it has been covered really recently. B ut here are the links:
http://www.diyaudio.com/forums/showthread.php?s=&threadid=3589&highlight=Aleph+bias+increase
http://www.diyaudio.com/forums/showthread.php?s=&threadid=5007&highlight=Aleph+bias+increase
http://www.diyaudio.com/forums/showthread.php?s=&threadid=8727
RALPH
http://www.diyaudio.com/forums/showthread.php?s=&threadid=3589&highlight=Aleph+bias+increase
http://www.diyaudio.com/forums/showthread.php?s=&threadid=5007&highlight=Aleph+bias+increase
http://www.diyaudio.com/forums/showthread.php?s=&threadid=8727
RALPH
To answer the questions anyway,
about 50 mv is my standard for DC offset in Alephs. If
you need to trim it you can do so in a number of places,
but adjust the the Source resistance in the current source
which biases the differential input transistors is a good
place.
Yes, you can increase the bias easily enough using the
resistor which feeds the Base of the NPN transistor on the
positive current source. I forget the number, but its the one
which goes from the Base to a capacitor which is charged
by a resistor to the positive supply.
Simply removing this will up the bias without any other
alterations needed.
about 50 mv is my standard for DC offset in Alephs. If
you need to trim it you can do so in a number of places,
but adjust the the Source resistance in the current source
which biases the differential input transistors is a good
place.
Yes, you can increase the bias easily enough using the
resistor which feeds the Base of the NPN transistor on the
positive current source. I forget the number, but its the one
which goes from the Base to a capacitor which is charged
by a resistor to the positive supply.
Simply removing this will up the bias without any other
alterations needed.
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