Thanks PRR.I will give the values
according to the mirrored image and values you kindly posted)
R1:10ohm
R2:10k
R3:600ohm
R4:10ohm
R5:100ohm
R6:3k
R7:5k1
R8:3k
R9:3k
R10:3k
R11:10ohm
R12:10ohm
Opps! Sorry! I flipped it to make more sense to my eye when going from topside to copperside view.
R3 is 600 ohms? That seems very odd. Either this is a mix-amp or someone was wedded to 600O systems (which were already going out of fashion). I would arbitrarily replace R3 with 10KO for now.
My best guess is that it starts to work right at +/- 22.8 volts. +/-24V therefore seems reasonable, but the current in the output stage goes up very fast as the supply voltage goes up. (The downside of the simple resistor in the input emitters.)
It is still starved at +/-18V. Even though it may "work", it will have crossover distortion.
Consider replacing R1 and R4 with 100O resistors. It gives a little more supply decoupling, and "softens" the tendency to run-away if the supply voltage is over +/-24V.
If you have a +/-18V supply, start with that. With the external resistor connected, the output should sit very close to 0 volts. More than a tenth volt off of zero means it isn't working. If you can sweep the power slowly up to +/-24V, it may "snap" to zero volts around +/-22 or 23V. Or just try it on +/-24V, but keep a finger on it in case the output transistors (furthest from the connector) want to overheat.
PRR
I had a chance to look at the 101 amp.
It is similar in some respects to the Flickinger, but I'd say the Flick is quite a bit better.
They both use the (2nd) diff amp to do the phase splitting to drive the quasi-comp output stage, but instead of having differential drive to it, the SS drives just the base of one half, the other base tied off to a voltage reference.
The input stage is just one transistor instead of a diff pair, which puts the feedback at the emitter of the input transistor rather than into another high impedance node as provided by the (1st) diff pair in the Flickenger design.
It's a lot easier to see it and go "a ha" then it is to describe it though. I don't have a scanner...
Dan Kennedy