Input Sensitivity: 600mV Signal to Noise ratio: 90 dB Output Impedance: 4 or 8 Ohms Power Consumption: 90 Watts Dimensions: (H x W x D): 150mm x 200mm x 355mm Weight: 6 Kg each Price when new: $1200 The M400S have a timber fascia and a green power LED. The body is stainless steel with two large transformers, one power and one output. The valves are a 6922 dual triode on the input, a ECC82 dual triode as driver, and two EL34 output valves used in a push-pull, class AB configuration. The measurement point and screw adjustment terminals for adjusting the bias are also on the top of the unit.