Bluetooth Power Amplifier Board Stereo 2.1 Channel 2X220W+350W - HiFi

In this review of the Bluetooth Power Amplifier Board Stereo ZK-AS21, the bottom line is simple: this board is for DIY audio builders and hobbyists who want a compact, powerful 2.1 amplifier with modern inputs and respectable Hi-Fi ambitions. The reviewer found the TPA3251D2 class D chips deliver clear, loud output without excessive heat, and the module's flexible inputs (Bluetooth 5.1, AUX, USB, U disk) make it easy to drop into a small desktop or bookshelf system. If you need raw power and multiple input options in a compact package, this board is worth considering.

Key Features

• High-power 2.1 output: The board supplies up to 220W to each left and right channel and 350W to a subwoofer, letting small systems reach high listening levels with solid bass support.
• Flexible inputs: Built-in Bluetooth 5.1, AUX, USB and U disk support allow connections from phones, PCs, TVs and USB storage without extra converters.
• Modern Bluetooth control: The upgraded Bluetooth supports APP control, adjustable volume and timed shutdown for convenient remote tweaks and playlist interaction.
• TPA3251D2 class D chips: Uses two high-performance TI amplifier chips for efficient operation and low distortion across the audio band for cleaner sound at high power.
• Protection features: Short circuit, overcurrent, undervoltage and overheating protection reduce the risk of damage and allow automatic recovery from faults.
• Speaker compatibility: Supports a wide range of speaker impedances and power ratings, accommodating L&R channels from 30-220W and subwoofers from 30-350W.

Who It's For

This amplifier board suits DIY audio enthusiasts building powered bookshelf, desktop or compact home theater systems who need a single board solution for left/right and subwoofer channels with both wired and wireless inputs. It also fits makers integrating a high-power audio stage into custom enclosures or media furniture where space is limited and efficiency matters.

Those who should look elsewhere include users seeking an all-in-one consumer receiver with built-in voice assistants, HDMI switching or polished consumer remote controls; this module is a technical component rather than a finished living-room appliance and requires a suitable 12-38V power supply and appropriate speakers.

Pros & Cons

Pros

• High rated power per channel and a robust subwoofer output provide room-filling sound when fed with sufficient power.
• Multiple input options including Bluetooth 5.1 and USB make source connectivity straightforward and modern.
• Good build quality and efficient TPA3251D2 chips mean lower waste heat and cleaner sound under load.
• Comprehensive protection systems help prevent damage from wiring or thermal faults.

Cons

• Realized output depends heavily on supply voltage/current and input signal level, so users must provide an adequate power supply to reach rated power.
• Not a finished consumer product: some users may find the need for external enclosures, wiring and cooling inconvenient compared with ready-made amps.

Specifications

Model	ZK-AS21
Channels	2.1 (L + R + Subwoofer)
Output Power	2x220W + 350W (max, with sufficient supply)
Bluetooth	Version 5.1 with APP control
Audio Inputs	Bluetooth, AUX, USB, U disk, USB sound card
Power Supply	DC 12-38V, 10A recommended
Protection	Reverse connection, undervoltage, overcurrent, overheating, short circuit

Our Verdict

The Bluetooth Power Amplifier Board ZK-AS21 is a compelling choice for experienced DIYers who want a compact, high-power 2.1 solution with modern wireless and USB inputs. It delivers strong volume, clear sound courtesy of TI TPA3251D2 chips and useful protections, but needs a proper power supply and a bit of technical assembly to reach its full potential, making it a good value for builders rather than plug-and-play buyers.

Frequently Asked Questions

What power supply does this board need?
The board accepts DC 12-38V; for high output use a supply capable of delivering adequate current (10A or more) to reach rated power.

Can it drive passive subwoofers and speakers?
Yes; it supports both active and passive output modes and is rated for L&R speakers 30-220W and subwoofers 30-350W.

Does it include overheating and short-circuit protection?
Yes; the board includes protection for short circuit, overcurrent, undervoltage and overheating with automatic recovery when conditions safe return.