Simplistic NJFET RIAA

Update:
After fixing the MOSFET pin wiring,

1. I have voltage in and out. Didn't have good solder joint at Vin turret. Doh!

2. It does't regulate. Vin = Vout (39.5 volts) regardless of pot setting from min to max R.

3. LEDs light up, although the third one is not as bright as the other two.

3. Read some voltages at MOSFET Pins:
For Q1, gate = 34.9 V source and drain = 39.4 V
For Q4 gate and source - 39.4 V, Drain = 0 volts.

My probe slipped, briefly shorting S and D on Q4.

Any suggestions.
 
Sorry off topic cant post picture on PM
 

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I'm back.

I misspoke earlier; It is actually the first LED that looks dimmer. Each drops 1.8-1.9 volts. 5.65 V all together.
R4 shows 20.5 V drop.
R5 shows 0.6 V drop.

Yes I have a spare Q2.

FdW: got it now thanks. that makes sense.

Doug

Q3 change fixed a number of voltages. Before changing Q2 which is inline loading it and if there is a hit in the error amp they form they usually die together, please look is there completed resistive path from Q5's drain through R7 and trimmer to V+ force AND sense when not tied together at a dummy load? What value is the dummy load again?
 
AAARRRGGGHHHH

OK. Replaced Q2 before I got your last message Salas.
Vin now reads 21 V instead of 40. (Voltage sag??) Diodes read OK in raw supply.

Anyway, Q1 now gets warm. Q4 still cold.

Pot resistance measures 0 to 4.7 kohm.
Q5/R7 node to Force (+) is big, about 8 megohm or OL.
Q5/R7 node to Sense (+) goes from 3.3 kohm to 8 lohm depending on pot setting.

V drop across R4 is 20.4 V
V drop across R5 is 0.55 V
Vdrop across R7 is 2.7 V
V drop across R1 is 2.2 V

Vin about 21 V
Vout with load (500 ohm) is 3.5 V
Vout with no load is 10.8 V

Q1 G to S = 3.3 V
Q4 G to S = 3.4 V

Q2 G to D = 3.4 V
Q3 B to E = 0.7 V
Q5 G to D = 0.7 V
Q6 B to E = 0.6 V
Q7 B to E = 0.54 V

What next boss?