The Sound Town STPA3L-400D Class-D plate amplifier enables you to build your own powered speaker cabinet. The STPA3L-400D power amp is equipped with two 1/4” line inputs, two 1/4” mic & XLR combo inputs, one 1/8” AUX input and one XLR loop output connector. The built-in Bluetooth allows you to connect with your Bluetooth enabled mobile devices instantly. The onboard two-band EQ per input channel helps tune the sound to your preference. Simply turn the treble or bass knob and adjust the level of high or low frequencies to match your audio signal perfectly.

The plate power amp generates 400W RMS (8-ohm) and comes with overload protection. When paired with the right speaker driver and enclosure, it produces clear and massive sound to reinforce your PA system.

  • 400W Class-D power amplifier plate
  • 2-channel 1/4" line inputs, 1 XLR and 1/4" mic combo input and 1 1/8” AUX input
  • 1 XLR loop output
  • Bluetooth connectivity
  • 2-band EQ with bass and treble control


Model STPA3L-400D
Description 3-channel input plate amplifier
Type Class-D
Impedance Supports 4Ω & 
Power 400W RMS
Feature Bluetooth, 3-channel input
Input 2-channel 1/4" (LINE) / 1/4" & XLR combo (MIC) + 1 channel 1/8" (AUX) / Bluetooth
Output XLR (3-channel loop out)
Control Master volume; each channel: treble, bass, gain
Protection Overload and overcurrent protection
Technical specifications Crossover point: 2.5k hz
Voltage 110V-220V switchable
Speaker model# reference KALE-112BPW

Dimension & Weight
Product Width (in.) 6.5"
Product Height (in.) 16.5"
Product Depth (in.) 3.5"
Product Weight (lb.) 6.7 lbs

Manufacturer Warranty 1 Year