I have a schematic of an Op being used as a buffer, I think. It is powered by twelve volts and seems to be biased by a voltage divider.
the non-inverting input receives the audio signal from a phone through an audio jack.

I would assume one could leave out the resistor R1 and R2 and just connect pin 6 to pin 2 to configure it as a 1AV (gain) op amp as well as the two rails.

so my question is:

what are the resistors being used for and what formulas are relevant if this is a biasing method.

feedback would help me greatly.

 

And posting the schematic would help us greatly.

 

OH JEEPERS haha... silly me.

 

Why would you assume you could remove R1 and R2?
Those resistors DC bias the op amp near 1/2 the supply voltage (for single supply operation) so that it can amplify both the positive and negative half of the input AC signal without clipping.

Typically the two resistors are equal value. You then calculate C1 to be large enough to give the desired low frequency corner with the equivalent resistance of R1 and R2 in parallel (fcorner = 1/(2πRC).

So you can't remove those resistors if it's operating from a single supply voltage.
You could if it were powered from a dual ±supply.

 

Oh i see, that makes sense. Thank you for your response.