The circuit design is modified based on Audio Research preamplifier and the design values are optimized. It supports both single-end and balance input and output (RCA and XLR). Basically, the circuit is differential amplifier with two cascade stages. The input stage uses 12AU7 with moderate voltage gain, whereas the output stage uses 6DJ8 (6N11). The differential amplifier provides high PSRR and capability to noise rejection. The signal paths of this PCB layout are designed in symmetry for both channels. Dedicated power rails, ground, and signal paths, altogether are taken into designconsiderations so that all are to minimize the parasitic, cross interference, and influence of RFI.