ITEM NAME:NE4558 Amplifier Board with Four Buttons for Treble, Bass, Balance, Overall Description: Module: DX338A series preamplifier volume control boardï ¼â€ºVoltage: dual AC12v Operational amplifier type: NE4558 (with four buttons for treble, bass, balance, total volume control). AA-type tone circuit technology, capable of driving composite dynamic impedance load headphones, combined with attenuated tones. With four 25V 1000UF filter capacitors. With equal loudness and through switch for improving sound characteristics. The circuit board has reasonable wiring, low noise, and beautiful component layout. Package Includes: 1 Piece Preamplifier Volume Control Board SKU: CKX0014913368008101.AA-type tone circuit technology, capable of driving composite dynamic impedance load headphones, combined with attenuated tones. The circuit board has reasonable wiring, low noise, and beautiful component layout.