{"product_id":"zk-st21-100wx2-200w-2-1channel-bluetooth-amplifier-board-high-power","title":"ZK-ST21 100Wx2+200W 2.1Channel Bluetooth Amplifier Board - High Power","description":"\u003cp\u003eIn this review the ZK-ST21 2.1 channel amplifier board is evaluated as a compact, high-power option for hobbyists and DIY installers who need a reliable amplifier for car or small home theater use. The bottom line is that it delivers genuinely powerful sound for its size thanks to dual TPA3221 HIFI chips, and the wide 12-30V input range makes it especially attractive for vehicle installs. It is best for someone who wants a plug-and-play amp with multiple inputs and simple tonal control, rather than a finished consumer-facing amp enclosure.\u003c\/p\u003e\n\u003ch2\u003eKey Features\u003c\/h2\u003e\n\u003cul\u003e\n \u003cli\u003e\n\u003cstrong\u003eHigh output:\u003c\/strong\u003e The board provides 100W per stereo channel plus a 200W subwoofer channel for a true 2.1 configuration capable of driving bookshelf speakers and a powered subwoofer with authority.\u003c\/li\u003e\n \u003cli\u003e\n\u003cstrong\u003eDual TPA3221 chips:\u003c\/strong\u003e The use of dedicated TPA3221 HIFI chips ensures cleaner amplification and improved headroom compared with single-chip designs at similar power levels.\u003c\/li\u003e\n \u003cli\u003e\n\u003cstrong\u003eWide voltage compatibility:\u003c\/strong\u003e The 12-30V DC input supports stable operation in varied vehicle electrical systems and many home battery setups without a separate regulator.\u003c\/li\u003e\n \u003cli\u003e\n\u003cstrong\u003eVersatile inputs:\u003c\/strong\u003e Bluetooth, AUX, and USB drive connectivity let the board accept audio from phones, TVs, laptops, and USB storage for flexible source options.\u003c\/li\u003e\n \u003cli\u003e\n\u003cstrong\u003eTone control:\u003c\/strong\u003e Dedicated bass and treble knobs allow quick, on-board adjustment to refine low-end impact or high-frequency clarity to suit room or vehicle acoustics.\u003c\/li\u003e\n \u003cli\u003e\n\u003cstrong\u003eBuilt-in protection:\u003c\/strong\u003e Short-circuit, over-current, overheat and reverse-polarity protections help safeguard speakers and the board during extended use or accidental wiring errors.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch2\u003eWho It's For\u003c\/h2\u003e\n\u003cp\u003eThe ZK-ST21 is aimed at DIY installers, mobile audio enthusiasts, and anyone building a compact 2.1 system who needs substantial power without a bulky amplifier chassis. Its wide voltage range and Bluetooth make it particularly useful for car conversions, marine projects, and custom home theater cabinets where space and flexibility matter.\u003c\/p\u003e\n\u003cp\u003eIt is not aimed at users who want a finished, rack-ready consumer amplifier with cosmetic trim, remote control, or built-in speaker outputs in an enclosed case. Buyers who need ultra-compact low-power desktop audio or full-featured AV receivers with room correction should look elsewhere.\u003c\/p\u003e\n\u003ch2\u003ePros \u0026amp; Cons\u003c\/h2\u003e\n\u003cp\u003e\u003cstrong\u003ePros\u003c\/strong\u003e\u003c\/p\u003e\n\u003cul\u003e\n \u003cli\u003eHigh combined power for a board-level solution, delivering strong stereo and subwoofer output.\u003c\/li\u003e\n \u003cli\u003eFlexible connectivity with Bluetooth, AUX, and USB drive support for multiple audio sources.\u003c\/li\u003e\n \u003cli\u003eOn-board bass and treble controls give quick tonal shaping without external EQ gear.\u003c\/li\u003e\n \u003cli\u003eRobust protection circuitry reduces risk from wiring mistakes or thermal stress during long sessions.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003e\u003cstrong\u003eCons\u003c\/strong\u003e\u003c\/p\u003e\n\u003cul\u003e\n \u003cli\u003eBoard-level format requires the user to provide mounting, enclosure, and speaker wiring, so it is less plug-and-play for non-technical buyers.\u003c\/li\u003e\n \u003cli\u003eNo included remote or display for source navigation on USB or Bluetooth playback.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch2\u003eSpecifications\u003c\/h2\u003e\n\u003ctable\u003e\n \u003ctr\u003e\n\u003ctd\u003eChannels\u003c\/td\u003e\n\u003ctd\u003e2.1 (stereo + subwoofer)\u003c\/td\u003e\n\u003c\/tr\u003e\n \u003ctr\u003e\n\u003ctd\u003ePower Output\u003c\/td\u003e\n\u003ctd\u003e100W x2 + 200W subwoofer\u003c\/td\u003e\n\u003c\/tr\u003e\n \u003ctr\u003e\n\u003ctd\u003eAmplifier Chips\u003c\/td\u003e\n\u003ctd\u003eDual TPA3221 HIFI chips\u003c\/td\u003e\n\u003c\/tr\u003e\n \u003ctr\u003e\n\u003ctd\u003eInput Options\u003c\/td\u003e\n\u003ctd\u003eBluetooth, AUX, USB drive\u003c\/td\u003e\n\u003c\/tr\u003e\n \u003ctr\u003e\n\u003ctd\u003eVoltage Range\u003c\/td\u003e\n\u003ctd\u003e12-30V DC\u003c\/td\u003e\n\u003c\/tr\u003e\n \u003ctr\u003e\n\u003ctd\u003eTone Controls\u003c\/td\u003e\n\u003ctd\u003eBass and Treble knobs\u003c\/td\u003e\n\u003c\/tr\u003e\n \u003ctr\u003e\n\u003ctd\u003eProtections\u003c\/td\u003e\n\u003ctd\u003eShort-circuit, over-current, overheat, reverse polarity\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/table\u003e\n\u003ch2\u003eOur Verdict\u003c\/h2\u003e\n\u003cp\u003eThe ZK-ST21 board is a strong value for DIYers and installers who need a powerful, flexible 2.1 amplifier without a full chassis. Its dual TPA3221 design, wide voltage range, and multiple inputs deliver room- or vehicle-ready performance, while on-board tone controls and safety protections make it practical for extended use. Recommended for those comfortable with board mounting and wiring, but not the best choice for buyers seeking a finished consumer amplifier.\u003c\/p\u003e\n\u003ch2\u003eFrequently Asked Questions\u003c\/h2\u003e\n\u003cp\u003e\u003cstrong\u003eCan this run directly from a car battery?\u003c\/strong\u003e\u003cbr\u003eYes, the 12-30V DC input means it can run from typical car electrical systems when installed with correct wiring and fusing.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eDoes it support playback from a USB thumb drive?\u003c\/strong\u003e\u003cbr\u003eYes, the board accepts USB drive input for direct playback from stored audio files.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eIs a separate crossover needed for the subwoofer?\u003c\/strong\u003e\u003cbr\u003eThe board provides a dedicated sub output and onboard tone controls, but users may choose an external crossover for more precise subsonic filtering depending on the speaker setup.\u003c\/p\u003e","brand":"Wuzhi Audio","offers":[{"title":"Default Title","offer_id":48235554504923,"sku":"B0F7W7M17G","price":35.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0724\/1043\/1707\/files\/71OooJeNPqL._SL1500.jpg?v=1770837693","url":"https:\/\/gearmusthave.com\/products\/zk-st21-100wx2-200w-2-1channel-bluetooth-amplifier-board-high-power","provider":"GearMustHave","version":"1.0","type":"link"}