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Green rectangular amplifier board with silver heatsinks, black knobs and antenna wire

ZK-MT21 2.1 Channel 50W x2 +100W Bluetooth 5.0 Amplifier Board

SKU CH-STES-DFN9A

A 2.1 channel amplifier board delivering 50W per stereo channel and 100W to a subwoofer, with Bluetooth 5.0 and 3.5 mm AUX input, plus treble and bass controls

  • 1 channel stereo plus 100 W subwoofer output for full-range sound
  • Bluetooth 5.0 wireless streaming up to 49 feet without cables
  • 5 mm AUX input for wired sources when Bluetooth is off
  • Independent treble and bass knobs let you shape the tonal balance
  • Over-voltage, under-voltage, over-heat and short-circuit protection built in

Compact 2.1-channel amplifier board

The ZK-MT21 is a stereo-plus-subwoofer amplifier module rated at 50 W per channel and 100 W for the subwoofer output. It accepts a DC supply between 12 V and 24 V, making it suitable for DIY speaker builds or compact home-audio upgrades. Bluetooth 5.0 provides wireless streaming up to 49 feet without obstructions, while a 3.5 mm AUX jack offers a wired alternative when Bluetooth is disconnected.

Sustained thermal protection

The board integrates over-voltage, under-voltage, over-heat and short-circuit protection circuits that engage continuously during extended playback. A large-capacity energy-storage capacitor and four low-noise preamplifiers help keep distortion low even when the module runs at higher output levels for long periods. The included enclosure shields the circuitry and assists with heat dissipation so performance remains stable during movie marathons or all-day listening sessions.

On-board tone controls and antenna option

Independent treble and bass knobs sit directly on the module, allowing real-time frequency shaping without external hardware. An antenna-holder solder joint is provided for an external antenna, which can extend wireless range in difficult layouts. The 2.1-channel speaker terminals support loads from 4 to 8 ohms, so the board works with a wide variety of bookshelf or satellite speakers paired with a passive subwoofer. It is not for buyers who need balanced line inputs, multi-room synchronisation or integrated DSP presets.

Highlights

  • 1 channel stereo plus 100 W subwoofer output for full-range sound
  • Bluetooth 5.0 wireless streaming up to 49 feet without cables
  • 5 mm AUX input for wired sources when Bluetooth is off
  • Independent treble and bass knobs let you shape the tonal balance
  • Over-voltage, under-voltage, over-heat and short-circuit protection built in

Specifications

No published specifications for this item yet.

Questions about this item

How much heat and power draw should I expect from the ZK-MT21 when running continuously at full output?

The board operates on a DC 12-24V supply and delivers up to 50W per channel plus 100W for the subwoofer. Built-in over-heat protection will shut it down if temperatures exceed safe limits during extended use.

What power supply and speakers do I need to have ready before this amplifier will work?

You must provide a DC power source between 12V and 24V. Connect passive speakers rated 4-8 ohms for the stereo channels (20-100W) and a matching passive subwoofer for the 100W mono output.

Will the ZK-MT21 integrate with my older 3.5mm source devices and existing passive speakers?

Yes. A 3.5mm AUX input is provided for wired legacy sources, and the speaker terminals accept standard passive speakers rated 4-8 ohms. Remember to disconnect Bluetooth before using the AUX input.

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