It is a useful tool for everyone who want to gain more dB in low frequencies. The system has the option to select the cutting frequency in the given range. Values of the components were selected in tests. There is also an indicator of the output stage and a transformer to supply the small tubes which illuminate the front and inside of RACK.
This device is perfect for both small parties (two full-bands) and big events (additional two basses powered from a separate amplifier through a filter cutting higher frequencies).
+/-12V supply of filters system, + of which is also used to supply the indicators (U 267) on LEDs. Input and output sensitivity – 0dB. Transformer for tubes – 12V 50W switched by a separate switch.