Blue Robbie - Class A discrete tube microphone and instrument preamplifier, one of the quietest (-131 dB EIN @ 50 Ohm) and most detailed (THD 0.006%) tube preamps available. The front panel features only a large backlit potentiometer (gain) and 1/4" hi-Z instrument input. On the back, you’ll find the power connection, power switch, balanced XLR mic input, balanced XLR line output, polarity switch, -20 dB pad, input selector switch (mic/instrument) and phantom power on/off. Maximum input level (8dB gain, 20Hz-20kHz): +22dBu w/o pad; maximum output level (20Hz-40kHz @ 10 kOhms): +34dBu. Dimensions: 8 1/2"x8 1/4"x5 1/4"