How did you check the drivers?
there is a risk that they test OK with the DMM or battery powered component tester, but as soon as you push hard, the drivers blow up
Here are the picture.
you can see that the orange input cap has a very ESR - about 38 ohm and 90 nf capacitance.
the other pictures should that some caps were simply open on the Atlas tester and show a very high ESR on the SR715.
Some caps were in very good condition also.
Strange actually...
Here is the model I got on a web page
.model 2sc945 npn
IS=3.577E-14 BF=2.382E+02 NF=1.01 VAF=1.206E+02 IKF=3.332E-01 ISE=3.038E-16 NE=1.205 BR=1.289E+01 NR=1.015 VAR=1.533E+01 IKR=2.037E-01 ISC=3.972E-14 NC=1.115 RB=3.680E+01 IRB=1.004E-04 RBM=1 RE=8.338E-01 RC=1.557E+00 CJE=1.877E-11...
Great catch indeed
here is the new simulation:
Steve: as you mentioned - not much change.
I will re--open up the 1060 I have the bench and measure - this weekend.
Thanks for the feedback!! need new glasses :)
not much change.
Maybe my 2SC945 spice model is not correct - I found it on a forum - Microcap did not have it.
but is plays the same role as a diff amp - that is why I called the 1060 diff amp.
I guess that is the way they cut costs - rather than a true diff amp with transistor+diode/zener based current source in the tail like in the 510
Here I know how to calculate the circuit... as the current in...