Rupert Neve Designs Portico 5017, Microphone preamplifier, Two channel operation, Silk function, Mic gain from 0dB to 66dB, DI Gain from 0db to 30dB, DI input balanced or unbalanced Hi-Z for instruments, high pass filter: Signals below 80hz can be attenuated at a rate of 12db / octave, switchable 48v phantom power, phase invert switch, Vari-Phase, threshold: When signals exceed the "threshold" level, the gain is reduced at a controlled 2:1 ratio, with attack and release time constants set to standard or fast depending on the internal jumper setting