{"product_id":"bluetooth-power-amplifier-board-2-1-channel-50w-x2-100w-compact","title":"Bluetooth Power Amplifier Board 2.1 Channel 50W x2 +100W - Compact","description":"\u003cp\u003eIn this review of the ZK-MT21 Bluetooth power amplifier board, the bottom line is simple: it is for DIY audio builders and small home theater setups that need a compact 2.1 amplifier with modern wireless input and noticeable low-end power. The board pairs Bluetooth 5.0 connectivity with a 3.5mm AUX input, delivers up to 2x50W for left and right channels plus 100W for a subwoofer, and includes bass and treble controls to shape the sound. For anyone building store audio, square speakers, or a compact living-room subwoofer system, this module offers a straightforward upgrade path with built-in protection and robust connector choices.\u003c\/p\u003e\n\n\u003ch2\u003eKey Features\u003c\/h2\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eBluetooth 5.0:\u003c\/strong\u003e Reliable wireless streaming up to about 49 ft without obstruction for simple pairing with phones and tablets.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eAUX input:\u003c\/strong\u003e A 3.5mm AUX port provides a wired option for devices that lack Bluetooth or for lower-latency connections.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e2.1 channel power:\u003c\/strong\u003e Delivers a maximum of 2x50W for stereo channels plus 100W for a powered subwoofer to produce fuller home theater bass.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eTone controls:\u003c\/strong\u003e Separate bass, treble and subwoofer frequency and volume knobs let users tailor the sound for music or movie playback.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eProtection features:\u003c\/strong\u003e Built-in short circuit, over-current, overheat and anti-reverse protections protect the board and connected speakers under fault conditions.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eDurable connectors:\u003c\/strong\u003e Uses a copper DC connector and fence-type terminal with a common 5.5mm x 2.1mm power jack to handle higher current without heating.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch2\u003eWho It's For\u003c\/h2\u003e\n\u003cp\u003eThe ZK-MT21 suits hobbyists and installers building a compact home theater, store solicitation audio, or square speaker system who want both Bluetooth convenience and a proper subwoofer channel. Its tone controls and sub channel make it useful where a punchy low-end is desired without a bulky receiver.\u003c\/p\u003e\n\u003cp\u003eThose who need calibrated, room-correction features, network streaming, or integrated user interfaces should look elsewhere; this board is best used by people comfortable wiring a module into speakers and a 12V-24V power source, and who accept basic physical controls rather than software tuning.\u003c\/p\u003e\n\n\u003ch2\u003ePros \u0026amp; Cons\u003c\/h2\u003e\n\u003cp\u003e\u003cstrong\u003ePros\u003c\/strong\u003e\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003eCompact 2.1 design gives clear stereo plus a dedicated sub output for stronger bass impact.\u003c\/li\u003e\n\u003cli\u003eBluetooth 5.0 and AUX provide flexible input options for phones and wired sources.\u003c\/li\u003e\n\u003cli\u003eMultiple protections reduce the risk of damage from short circuits, overcurrent, overheating, or reverse wiring.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003e\u003cstrong\u003eCons\u003c\/strong\u003e\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003eModule-style form factor requires DIY installation and a separate enclosure for permanent use.\u003c\/li\u003e\n\u003cli\u003eNo onboard digital room-equalization or network streaming options for advanced systems.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch2\u003eSpecifications\u003c\/h2\u003e\n\u003ctable\u003e\n\u003ctr\u003e\n\u003ctd\u003eModel\u003c\/td\u003e\n\u003ctd\u003eZK-MT21\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eOperating Voltage\u003c\/td\u003e\n\u003ctd\u003eDC 12V-24V\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eOutput Power\u003c\/td\u003e\n\u003ctd\u003e2x50W + 100W (max)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eSpeaker Impedance\u003c\/td\u003e\n\u003ctd\u003e4-8 Ohm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eBluetooth Version\u003c\/td\u003e\n\u003ctd\u003e5.0 (up to 49 ft without occlusion)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eAudio Inputs\u003c\/td\u003e\n\u003ctd\u003eBluetooth + 3.5mm AUX\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eProtection\u003c\/td\u003e\n\u003ctd\u003eShort circuit, over-current, overheat, anti-reverse\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/table\u003e\n\n\u003ch2\u003eOur Verdict\u003c\/h2\u003e\n\u003cp\u003eThe ZK-MT21 is a practical, value-oriented amplifier board for DIYers and small home theater builders who want Bluetooth streaming plus a dedicated subwoofer channel. It combines useful tone controls, solid protection features, and durable connectors into a compact module; while not a polished consumer receiver, it represents good value where flexibility and raw power per dollar matter most.\u003c\/p\u003e\n\n\u003ch2\u003eFrequently Asked Questions\u003c\/h2\u003e\n\u003cp\u003e\u003cstrong\u003eWhat power supply does this board require?\u003c\/strong\u003e\u003cbr\u003eUse a DC 12V-24V supply capable of supplying at least 5A or higher depending on speaker load and desired output.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eCan I connect passive 4 ohm speakers?\u003c\/strong\u003e\u003cbr\u003eYes, the board supports 4-8 Ohm speakers; ensure the supply current and speaker power ratings are suitable for 50W channels and 100W sub output.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eDoes it have protection against wiring mistakes?\u003c\/strong\u003e\u003cbr\u003eYes, it includes anti-reverse connection protection plus over-current, overheating, and short circuit safeguards.\u003c\/p\u003e","brand":"DiGiYes","offers":[{"title":"Default Title","offer_id":46759913357531,"sku":"B0CW5ZF6FD","price":18.79,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0724\/1043\/1707\/files\/61-SEZXiivL._SL1500.jpg?v=1747854420","url":"https:\/\/gearmusthave.com\/products\/bluetooth-power-amplifier-board-2-1-channel-50w-x2-100w-compact","provider":"GearMustHave","version":"1.0","type":"link"}