Great, you don't need it. Great, then you haven't already wasted money on it. Don't. No problem, it wouldn't help you anyways. What? You set the output of the amplifier to 2V? They were telling you to set the input sensitivity to the 2V setting....not that that info is necessarily "correct" anyways. You would set it based on Ohms Law, if you were using the DMM method....which isn't necessary. But even then if you are using a 0db test tone you will end up unhappy with the results, more than likely. Best to just set it by ear. Neither, set it by ear. If you absolutely feel you must use a DMM to set the gain, then you would set it according to Ohms Law... sqrt(Power*Impedance) = Voltage But, see above. 200, or leave the DMM in the toolbox and set it by ear. All this plus setting it by EAR! prob the best gain setting response I've ever heard haha, nice.