BGD400 bargraph audio displays are an effective and economical means of displaying multiple audio lines. They can give you that warm comfortable feeling that there really is audio going out with your video, audio is feeding the switcher, and there definitely are outputs to your phone. 

Along with providing a nice touch of color for your studio, the BGD400-VU provide a good visual match to the ballistics of a standard ASA VU meter in bright, three color, and ten segment displays. 

The BGD400 is a four-channel unit with vertically oriented displays.  Two sections of a quad bi-fet IC, National LF347N, form a selectable gain, instrumentation amplifier input stage. The instrumentation amplifier provides precisely equal loading to each side of a balanced line with good common mode hum rejection yet will easily bridge a high impedance IHF level audio line (RCA connectors) from HI input to GND without the necessity of also grounding the LO input terminal.

Three position jumper plugs for each channel (JX02) select input stage gain for nominal 0 VU or 0 dB displays at -10, +4 or +8dBu input (0dBu reference is .775Vrms). Trimpots accessible through the front panel allow precise level trimming.