for a school project I'm trying to adapt a universal mic preamp to a piezo mic: obviusly with the original circuit i've obtained a low distortion.
I've read in another topic that R1//R2 = 50k is the input impedance.
Generally piezo preamps have an input impedance of minimum 1Mohm/max 10Mohm so I'm asking myself: can I change R1 and R2 resistors and make it work like an high impedance input?
This preamp in particular has a peak of 40mV for the input and a piezo mic has clearly several volts when you play your instrument with an hard dynamic and generate distortions.
Hope my topic is clear and thanks in advance for your advices (: