Problem Aleph5

[svemir]

I have built Aleph 5 but there is a offset "problem˝ on one chanel i get 12 mV but on other 110mV. I know the reason for that " unmatched˝ IRFP9610 on the input but is 110 mV realy bad or iz it akceptible?
Sory on my bad english.

[Netlist]

In terms of 'bad', it is a bit bad.
Try to find a better matched pair.

/Hugo

[RoboMan]

Originally posted by svemir
I have built Aleph 5 but there is a offset "problemÝ on one chanel i get 12 mV but on other 110mV. I know the reason for that " unmatchedÝ IRFP9610 on the input but is 110 mV realy bad or iz it akceptible?
Sory on my bad english.

You can adjust the offset by changing the value of R14 (392) or R11 (221, Source Resistor of Q3). You can parallel a resistor (say 1K or other values) to R11 and see how it works. If it gets higher, try to do it with R14.

[svemir]

Ok, thanks for the advice. I wil wait few days and see if something changes if not, back to the matching IRF9610.