JB Systems - AMP400.2 Mk2

AMP 400.2 Mk2 is the Mark II version of the well-known JB Systems AMP 400.2 professional power amplifier. It is a 2-channel class-D amplifier rated at 2 x 250 W RMS on 8 ohms and 2 x 450 W RMS on 4 ohms. Externally it maintains the particularly compact dimensions of the previous model, with a standard rack width of 19" and a height of 1 U (44 mm). Internally, however, the layout has been completely reworked to improve reliability and heat dissipation; By the way, three fans were used to keep the temperature controlled.

The project is based on the use of an extremely efficient soft start switching power supply. Three working modes: stereo, mono or bridged. Stereo mode is the conventional one in which both channels work separately. The mono mode is, basically, identical to the stereo one but with the inputs of both channels linked so that the output will be mono; in this case, only the LEFT channel input can be used to drive both output channels with the same signal. Finally, the bridge mode bridges the final stages for a power of 900 W on 8 ohms. A peak limiter prevents signal distortion, while a low cut filter cuts low frequencies at 75 Hz with a very steep filter at 24 dB/oct. The input sensitivity is variable according to values: 0.775 V / 1.0 V / 1.44 V to adapt to any source. There is also a rear switch for floating mass.

To prevent unauthorized persons from changing the input levels, a plastic cover (included) can be installed using 4 screws in front of the front controls. The amplifier inputs are balanced XLR, there is a link output for connecting another power amplifier in daisy chain, while the outputs are on speakON connectors.

Protections against short circuits, high temperatures and overloads.

Technical characteristics