VOKTTA ZK-TB21 series 2.1 channel Bluetooth audio amplifier board module subwoofer midrange treble TPA3116

VOKTTA. Model-specific functions. ZK-TB21 Basic model. Mobile phone APP control: support timed shutdown/10-band EQ adjustment. Mode memory function: automatically save the last used status. Core features: APP intelligent control/three-mode input switching AUX/Bluetooth/USB). Applicable scenarios: home theater system/multimedia audio. ZK-TB21S Enhanced model. Core features: four-dimensional input expansion new USB flash drive/USB sound card mechanical knob switch. Applicable scenarios: car audio modification/professional listening room. U disk direct reading: supports MP3/WAV format playback. Mechanical knob: one-button power on/off no standby power consumption). ZK-TB21F professional model. Core features: potentiometer separation design/extension interface support. Applicable scenarios: DIY audio engineering/performance equipment. Potentiometer external connection: control line can be extended to 3 meters. Extension interface: supports external microphone/reverberation preamplifier boa