BLA packed 4 B12A mic pres into 1 rack space to build the Quad. Plug into 4 channels with 70 dB of punchy API 312A-style gain, Cinemag transformers and all.
What's better than a Black Lion Audio 1073-style mic preamp? Four of them! The B173 Quad gives you 70 dB of clean gain with plenty of rich vintage character.