The m501 from Grace Designs is a 500 series microphone preamp module, based on the company's m101 microphone preamp. While the 500 series market has plenty of colored preamp options, the natural, musical clarity of the m501 makes it a welcome addition. This circuit is for engineers who wish to capture their sources with as little coloration or distortion as possible.
The m501 module features a balanced, transformerless design, with 48V phantom, a 75Hz high-pass filter, and a 1/4" HI-Z instrument input. Also standard is a ribbon microphone mode, which raises the input impedance, bypasses the input decoupling capacitors and deactivates 48V phantom to protect delicate ribbon microphones from damage.