Pioneer GM-X552 Service Manual - Page 21

GM-X552 21 Setting the Unit Gain Control If the sound level is too low, even when the volume of the car stereo used along with this power amplifier is turned up, turn gain control on the front of the power amplifier clockwise. If the sound distorts when the volume is turned up, turn the gain control counter-clockwise. • When using with an RCA equipped car stereo (standard output of 500 mV), set to the NORMAL position. When using with an RCA equipped Pioneer car stereo with max. output of 4 V or more, adjust level to match the car stereo output level. • If you hear too much noise when using the speaker input terminals, turn the gain control counter-clockwise. Power Indicator The power indicator lights when the power is switched on. BFC (Beat Frequency Control) Switch If you hear a beat while listening to an MW/LW broadcast with your car stereo, change the BFC switch using a small standard tip screwdriver. (GM-X552/X1R/EW,ES) LPF (Low-Pass Filter) Select Switch Set the LPF select switch as follows according to the type of speaker that is connected to the speaker output connector and the car stereo system: LPF Select Switch LPF (left) OFF (right) Audio frequency range to be output Very Low Frequency range Full range Speaker Type Subwoofer Full range Remarks Connect a subwoofer.