ZK-TB21 2.1 Channel Bluetooth 5.0 Amplifier Board 200W - Compact HiFi

Our review of the ZK-TB21 2.1 Channel Bluetooth 5.0 Amplifier Board finds it best suited to DIY speaker builders and hobbyists who want a compact, powerful amplifier with flexible inputs and tone control. The single biggest reason to consider this module is the combination of dual TPA3116D2 Class D outputs and Bluetooth 5.0 connectivity in a very small package, which delivers strong clean power for its size while keeping installation straightforward.

Key Features

• Bluetooth 5.0 wireless input: Quick pairing and stable streaming up to about 50 ft from phones or tablets thanks to the QCC3003 implementation.
• 2.1 channel output: Provides two channels of stereo plus a subwoofer output for fuller low end in compact speaker builds.
• Independent treble and bass adjustment: Onboard controls let you shape the tonal balance without touching the source device.
• Dual TPA3116D2 chips: Class D amplifier topology and shielding reduce distortion and deliver more efficient, low-noise power.
• Protective functions: Built-in over-voltage, under-voltage, over-heat and short-circuit protection help safeguard the module and attached speakers.
• Small form factor: At roughly 110 x 70 x 21 mm (4.4 in x 2.75 in x 0.78 in) the module fits into small enclosures and is easy to mount.

Who It's For

This amplifier board is aimed at DIYers assembling compact bookshelf systems, desktop speaker projects, or a powered subwoofer add-on who need a compact HiFi amplifier with both Bluetooth and AUX options. It is also useful for hobbyists who want onboard tone controls and protection circuits without building a separate preamp.

It is less appropriate for audiophiles who demand reference-grade components or perfectly transparent wireless performance; some users reported variable Bluetooth connectivity and a few noted sound differences depending on source. Also, those wanting a consumer plug-and-play powered speaker with factory support should look elsewhere.

Pros & Cons

Pros

• Compact but powerful output thanks to dual TPA3116D2 chips and class D efficiency.
• Onboard treble and bass controls provide quick tone shaping without additional gear.
• Multiple protections and a shielded layout reduce interference and protect connected speakers.
• Clear documentation on the protective plate simplifies installation for DIY builds.

Cons

• Bluetooth and sound quality received mixed feedback from some customers, so wireless performance can vary by environment and source device.
• AUX mode requires manual disconnection of Bluetooth, which is an extra step compared with automatic input switching.

Specifications

Model	ZK-TB21 2.1 Channel Amplifier Board
Channels	2.1 channel stereo + subwoofer
Output power	100W + 100W (stereo channels), subwoofer supported
Bluetooth	Bluetooth 5.0 with QCC3003 chip (approx. 50 ft range)
Size	110 x 70 x 21 mm (4.4 in x 2.75 in x 0.78 in)
Protection	Over-voltage, under-voltage, over-heat and short-circuit protection
Power input	DC 9-24V

Our Verdict

The ZK-TB21 is a strong value for DIYers who need a compact, protected Bluetooth amplifier with tone controls and genuine power for small speaker systems. It combines efficient TPA3116D2 class D amplification and useful protections in a small footprint, making it a practical choice for projects where space, power and basic tuning matter.

Frequently Asked Questions

Can this board run from a 12V car battery?
Yes, the amplifier accepts DC 9-24V, so a 12V supply is within the supported range, but ensure your power source can provide sufficient current for the desired output.

Does AUX input work while Bluetooth is connected?
The module requires Bluetooth to be disconnected to use AUX reliably, so switch off Bluetooth pairing when using the wired input.

Is this suitable for a powered subwoofer?
Yes, the 2.1 output supports a subwoofer channel and onboard tone controls help tailor the low end for a subwoofer application.