my old Yamaha subwoofer, was a beast when it used to work properly, there are some marks, but have tried my best to clean, the sub powers on but no audio output, it's currently wired for passive connections, so the sub will need to be opened up to go back to active if fixed, but the subwoofer speaker is in fully working condition so could be used DIY as it is a great driver, drop me any messages happy to answer.
eBay
500w CLASS-D digital power amplifier module ,subwoofer amplifier board subwoofer board
Aliexpress UK
In addition, this power amplifier board is also equipped with reverse phase subwoofer and closed subwoofer switch, so that each subwoofer can achieve good results. The materials are sturdy, with an aluminum backplate and almost no bottom noise.
eBay
Professional Digital Power Amplifier 4x1800W Class D Audio DJ Pre-Subwoofer Amp 2/4 Channel Line Array Speaker Sound Amplifier
Aliexpress UK
CT Sounds engineered the CT-2000.1D Compact Class D Monoblock Car Amplifier for anyone in need of a powerhouse amplifier that fits just about anywhere in your vehicle and won’t destroy your wallet. CT Sounds CT-2000.1D Compact Class D Car Audio Monoblock Amplifier, 2000 Watts RMS.
eBay
ShennDare D1650 Professional Digital Power Amplifier 4x1650w 8Ohm 4 Channel DJ Subwoofer Amplifier Line Array Speaker Sound Amp
Aliexpress UK
Enclosure Type - Slim Fit Bass Enclosure. Type - Active bass enclosure. • Auto sense circuit allows the amplifier to turn on and off when using high level input without the need for a remote turn on wire.
eBay
PA-80D Universal Car Amplifier Board 12V 1000W Mono Car Audio Power Amplifier Powerful Bass Subwoofers Amplifier For Car Modi
Aliexpress UK
(170 W) Powerful Bass, without losing space. This unique feature generates three selectable Bass Modes: DEEP, NATURAL and DYNAMIC, producing 170 Watts of strong, rich, deep bass that you can feel, without giving up space.
eBay
ShennDare PFA3001+CQ260DA Professional DSP Power Amplifier Module 1x1800W 8OHM Active Speaker Amplifier Module Subwoofer Amp
Aliexpress UK
NEW MODEL 12 “Twin Active Amplified Double Bass Box Sub Car Subwoofer Amp Amplifier 3600W. 2 x 12” WOOFER WITH TWO 40 OZ MAGNET. MAX POWER: 3600 WATTS. 2” VOICE COIL WITH PP CONE. FACTORY MATCHING CARPET TRIM.
eBay
Paulkitson PD43000 4x3000W 8Ω Professional Digital Power Amplifier 4 Channel Amplifier Line Array Speaker DJ Subwoofer Amp
Aliexpress UK
12” WOOFER WITH 50 OZ MAGNETS. Premium Quality OE AUDIO 12" Built in Amplified Active Single Subwoofer Box 1800 watts. SINGLE 12" ACTIVE ENCLOSURE Version 2. Depth at Bass: 36cm. 2” VOICE COIL WITH PP CONE.
eBay
12V Universal Car Amplifier Board 600W Mono Car Audio Amplifier Powerful Automobile Stereo Subwoofers Amplifier Car Accessories
Aliexpress UK
This is a high-quality subwoofer amplifier board. A low-cut is also designed, which cuts all the frequency below 18Hz, and converts the energy to the frequency range of 25Hz-60Hz, which makes people sound endless and full of energy.
eBay
AIYIMA Audio A1001 Subwoofer Amplifiers 100W TPA3116 Mono Power Amplifier Speaker Sound Amplificador Amp DIY Home Theater
Aliexpress UK