Two way adapter and preamp for using plug in power microphones (like the Roland CS10-EM) with a Tascam Dr-40. 48 volt phantom from the Tascam is used to power the preamps and supply the requisite bias voltage. Gain in this circuit is 10, also converts from stereo TRS to dual balanced XLR. When adjusting gain, all the feedback resistors need to maintain the same ratio to make sure both sides of the balanced audio have the same amount of gain. Basically, account for the difference between the inverting and non-inverting gain formulae. For example: (Non inverting feedback resistance [8.2K]) + (inbetween feedback resistance [1K]) = (Inverting feedback resistance [10K])