Common Mode Rejection
In the specification list, Voltage Gain: 120 dB refers specifically to the Open-Loop Gain (\(A_{OL}\)) of the amplifier.
What Open-Loop Gain Means
This is the raw, theoretical amplification power of the op-amp when there is absolutely no feedback loop connecting the output back to the inputs.
Expressed mathematically, a gain of 120 dB translates to a voltage multiplier of 1,000,000:
This means that if you were to apply a mere \(1 \mu V\) (one microvolt) difference between the inverting and non-inverting inputs without any feedback network, the op-amp would try to swing its output by \(1 V\).
Why This Matters for Your Circuit
In audio electronics and boutique pedal design like Bloodhoney, you will almost never run an op-amp in an open-loop configuration because the gain is so massive that even microscopic background noise would instantly drive the output into severe clipping against the power rails.
Instead, this massive open-loop gain provides the "headroom" necessary to make Negative Feedback work effectively. By routing a portion of the output signal back to the inverting input (Pin 2 or Pin 6) through a resistor network, you "tame" the amplifier down to a highly predictable and stable Closed-Loop Gain.
The huge surplus of gain (the difference between your closed-loop gain and the 120 dB open-loop gain) is what the op-amp uses to actively correct distortion, widen the bandwidth, and keep the audio signal incredibly linear and transparent.