Is opamp nulling in pre-amp circuit necessary?

[radioslicer]

Context: Pulse Induction circuits.

Is opamp nulling in the pre-amp circuit necessary?
I see it again and again, copied from one design to another. The signal is AC coupled to the next stage. You can see a cap before the next differentiator stage.
When left uncorrected, according to the DS https://www.onsemi.com/pdf/datasheet/ne5534-d.pdf
max offset is 3mV. Even if it's 30mV, the next stage takes a difference in voltages, so both the main and EFE sample voltage will offset the same amount.
What is the motivation for offset correction? What am I missing?

[Skippy]

Missing?
Disclaimer : I'm not a PI expert, but:
Take that middle circuit. DC gain is 1000 ( actually 1001 ... ) , so if the op-amp has 2mV input voltage offset, that means the two input pins need to be 2mV different, in order to get a sensible ( ie not saturated against the power rails ) opamp output. Which means the opamp out pin has to be 1000 x 2mV = 2 volts ( + or - as required ). Not ideal if you've got +/- 5V power rails, and an opamp that can't get within 1.5 V of the rails.
And that's not allowing for input bias currents into the opamp input pins, which flow through any resistors that surround the opamp, generating voltages, that get amplified, producing an output voltage, too.

[waltr]

Yep, what Skippy said. Offset nulling is needed due to the high gain to keep the output within the op-amp rail Voltage.

Just build the circuit and play with it to see.

[Carl-NC]

Even if you use a super-low offset opamp, you may be sampling a signal that has not fully settled to zero. Therefore, the offset adjust might be needed for signal offset instead of opamp offset.