ARRAROWN ZK-TB21 2.1 Bluetooth 50W×2 +100W Sub Amp

The ARRAROWN ZK-TB21 is a compact 2.1 Bluetooth 5.0 amplifier board that delivers 50W per stereo channel plus 100W for a subwoofer, with onboard treble and bass adjustment and multiple safety protections.

This small-form digital amp module is built for DIY home audio projects and upgrades where wireless streaming, a dedicated low-frequency channel, and hands-on tone control are priorities. The board combines Bluetooth 5.0 wireless input and a wired AUX option, a feature set intended to power bookshelf speakers, custom cabinets, or desktop systems with cleaner output and adjustable tonal balance.

How does the ZK-TB21 connect to sources and speakers?

The module supports Bluetooth 5.0 for wireless audio streaming and includes a separate AUX input for wired devices. It outputs in 2.1-channel configuration—left and right stereo channels plus a dedicated subwoofer output—so you can drive two satellite speakers and one powered or passive subwoofer with a crossover.

• Bluetooth 5.0 wireless pairing for phones, tablets, and laptops
• 3.5mm or RCA AUX input for non-Bluetooth sources
• Dedicated speaker terminals for left, right, and subwoofer outputs
• Use AUX only after disconnecting Bluetooth to prevent input conflicts

What tonal controls and sound-quality features are available?

The board has independent treble and bass adjustment knobs, letting you shape highs and lows without changing the playback device. Internally, a low-noise front-stage op-amp and shielding components help reduce interference and deliver clearer midrange and sub-bass performance.

• Onboard bass and treble controls for quick tonal tweaks
• Low-noise preamp stage to minimize hiss and distortion
• Shielding and inductance design to suppress AM interference
• 2.1 architecture separates bass duties to the subwoofer for tighter low end

Is the amplifier safe and easy to install for DIY builds?

The ZK-TB21 includes multiple protective circuits—over-voltage, under-voltage, over-temperature, and short-circuit protection—plus a fitted case with interface labels printed on the plate. Its small footprint and clearly marked connectors make mounting into speaker cabinets or compact enclosures straightforward even for first-time builders.

• Protection against voltage faults, overheating, and shorts
• Compact dimensions (about 4.72 × 3.94 × 0.7 in) for tight builds
• Printed interface labels on the protective plate speed installation
• Includes shielding and filtering for more stable operation

Who is this for? The ARRAROWN ZK-TB21 is aimed at hobbyists and small-scale installers who want a modern Bluetooth-capable 2.1 amp for custom speakers, desktop audio systems, or refitted vintage enclosures. It suits anyone looking for stronger bass management via a dedicated sub channel, hands-on tone control at the amplifier, and a compact unit that offers robust protections. Avoid using the AUX input while the board remains paired to Bluetooth—best practice is to clear the wireless connection before switching to wired sources.