The SM-400S Bass Amplifier provides the power, performance, flexibility and portability needed by the professional bass musician for every style of playing and nearly every situation he/she will encounter. To accomplish the above statement, we had to use almost every imaginable type of electronic component available. This added up to an all TUBE preamp section, a limiter using Field Effect Transistors, tone and equalizer controls utilizing Integrated Circuits and two individual power amps employing discreet, solid state devices. The power amplifiers in the SM-400S can be used individually to provide full biamp capabilities when used with the built-in adjustable electronic crossover or can function as stereo, 250 watt power units. If you need more power, the amps can be bridged for 400 Watts @ 8 ohms or 550 watts @ 4 ohms. The power amps are cooled by a thermostatically controlled fan. Front panel features include Hi and Low Gain input jacks, Gain and Master Volume controls, Integral Limiter and an exclusive feature we call an Aural Enhancer. Tonal flexibility is achieved with Bass, Treble and Transparency controls and a 4 band Variable Graphic Equalizer. The Crossover Frequency Control adjusts the crossover points of the electronic crossover and the Balance control adjusts the levels of the two power amps when used in the stereo mode. The back panel features and XLR Balanced Out switchable for direct and line out, XLR Pad w/gnd lift, Crossover High and Low Frequency Output jacks, and Mono and Stereo Effects loops. A power amp assign switch selects stereo or bridge mode and for speaker outputs, there are two jacks each for left and right out or one banana jack for mono operation. The SM-400S is rack mountable, taking up two rack spaces (3 1/2") by 11 3/4" deep. It is housed in an all aluminum chassis for light weight and lasting beauty and weighs just over 18 pounds. It is easily carried by the handles secured to the front panel. The tube employed in the preamplifier is a specially selected Groove Tube 12AX7A.