Sound Town STP Series Power Amp Plates for PA Speakers and Subwoofer (700W RMS,Class D, w/High-Pass Filter Outputs) : Amazon.co.uk: Electronics & Photo
Final s110 Subwoofer + diy plate amp. 45€ total : r/BudgetAudiophile
Seismic Audio SA-APEF01 1200w PA Subwoofer Speaker Plate Amplifier | Reverb España