Features 1、Onboard bass frequency regulator potentiometer can make a relatively wide adjustment, so that subwoofer can be blend in the mid‑to‑treble harmoniously without a sense of violation 2、Phase switch designs, both noninverting amplifier and see‑saw amplifier are compatible to use 3、Dual 5532 2.0 full‑tone + 0.1 bass structure can control the volume of each channel of 2.0+0.1, adjustable bass frequency phase with powerful bass 4、Both full frequency and bass output signals have independent interfaces, which is very convenient 5、Support both DC 12‑30V and AC 9‑20V input voltage, powerful and practical Specification Item Type: Preamp board Material: Synthetic cardboard Chip Model: NE5532 78M12 Architecture: Dual 5532 2.0 full tone + 0.1 bass Frequency Range: Full tone 20-20KHz / bass 20-200Hz Features: 2.0+0.1 Controllable volume, adjustable bass frequency and phase Package List 1 x Preamp Board