Here's my Issue:
I finished the build but now i’m running into problems calibrating the ms76.
PSU-voltages are fine and of course i’m sticking to the calibration-guide
CH1:
Input-meter works fine.
when trying to calibrate the q-bias, i’m unable to adjust the output-level to 0dB, maximum is about -20dB on the MS76-Meter
in my DAW the input reads 10dB less than the DAW-output.
when trying to adjust zero, the meter stays at around -7dB, it doesn’t move at all when adjusting the zero trimmer.
CH2:
In VU-In mode, the needle jumps to maximum right, even if there’s no signal present.
when trying to adjust zero, the meter stays at around -7dB, it doesn’t move at all when adjusting the zero trimmer.
VU-Out max. Level is also around -20dB on the Meter, in the DAW it’s almost 10dB less on the input.
Unfortunately I’ve made a silly mistake when hooking up the PSU. I accidentally connected -15 to GND, +15 to -15, +30 to +15, -10 to +30, +12 to -10 and GND to +12
Well, this is what happens when you’re almost done and get careless.
I could hit myself for doing this...
FYI: i’ve added the LL5402 in my build.
And here's Gustavs reply (by mail):
In the areas around the transistors, there are approximate voltages. Check those first.
Then, I would look for fried ICs.
Your note on the Q-bias seems odd, maximum is -20? You should set it, so reading is +1, and you adjust it Down to 0 in GR mode.
If that doesnt Work out – try adjusting the q-bias out of the way, then calibrate the meter, and try Again.