UniEngineer

Hi, I am designing an audio preamplifier with the following specifications: Gain Stage: Input 1: Low impedance source (1.2k) balanced input (differential i/p plus ground) with a variable gain of 0dB to 60dB Input 2: High Impedance source (10k) unbalanced (signal plus ground) with a variable gain of 0dB to 40dB. I have decided to use an instrumentation amplifier for the first input, I have a designed circuit but im not sure on how to work out the component values of the resistors and POTs. Are there any rules of thumb i need to apply?