No matter what your application, the M-1 will provide superior sound quality. The world's best input transformer (Jensen JT-16-B), best op-amp (990 discrete op-amp) and the elimination of all capacitors from the signal path combine to provide the highest performance. The M-1 has a 19" wide mainframe rack-mount chassis (1.75"H x 19"W x 8"D) and can be ordered with 1 to 4 channels. There are two meter options and the best Jensen output transformer (JT-11-BMQ) is also available as an option. Additional channels and options can be easily added later up to the total capacity of the mainframe. The M-1 was introduced in 1987 and while sonically identical to the M-2 there are a few control differences. The M-1 has a two-section gain-pot providing continuously variable adjustment in two overlapping ranges that are selected by the "HIGH GAIN" switch. (The M-2 has a 16 position gain-switch with 1% metal-film resistors providing accurate and repeatable gain settings. Since the "HIGH GAIN" switch isn't necessary, the M-2 is available with either a "20 OHM MIC" switch OR a "20dB PAD" switch).