THAT1512 / Transformer 'blind test' mic preamp

[dmp]

Another thing I don't understand is how the circuit is unbalanced in the SPICE simulation when the pot is set exactly half-way. My understanding was that it's there to adjust for tolerances in the resistors, but in the simulation, the resistors are all exact values.

I feel like I'm missing something really fundamental here.

The top opamp is inverting while the bottom opamp is non-inverting. The gain is different, Rf/Rin vs 1+Rf/Rin

 

[Newmarket]

The top opamp is inverting while the bottom opamp is non-inverting. The gain is different, Rf/Rin vs 1+Rf/Rin

The cross coupling (see R32, R33) takes care of that.

Below is as implemented in DDA AMR24

 

[amplexus]

I’ve used both the DRV and THAT chips with no output coupling caps with no issues. Just make sure you have the caps to the SENSE lines and you should be golden.

 

[dmp]

The cross coupling (see R32, R33) takes care of that.

Then why do the top and bottom have different pk-pk magnitudes?