This is Groove Tubes' award winning all tube mic preamp. Five unique and meaningful features that no other preamp offers. Eight-tubes, fully-differential (balanced) signal path with 75dB total gain via precision 1dB and 5dB stepped attenuators, four variable transformer impedances PLUS two balanced-bridged inputs, five variable rise-time settings, precise VU meter with five viewing options, separate +4dB and -10dB transformer outputs, microphone and +4dB line level balanced inputs. Separate instrument input with two options for input sensitivity.