Ok I'm new to all this. i figured out how to bias a transistor, doing ok with R/C/ circuits and filtering. doing ok building transistor pre amps for guitar, clean and distorted. PROBLEM, OP AMP i cant figure out the offset voltage/current the best i can tell is. no resistor connecting the + or - power supplys to the op amp i understand the neg feed back and the gain ratio. just not sure if i shouid use 5K and 50K or 15K and 150 K for a gain 10 and explain the voltage divider for single power supply. i know how to make a divider, just not sure where to put it in the circuit.