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September 17, 2025
Question

Issues setting up ZY-2.1BT 2.1 Bluetooth amplifier with speakers

  • September 17, 2025
  • 1 reply
  • 502 views

Hi everyone,

I recently got a ZY-2.1BT 2.1 channel Bluetooth digital power amplifier board to test out as part of a DIY audio setup. The idea is to run two bookshelf speakers plus a subwoofer from a single board, mainly for a small home theater project.

Setup Details:

  • Power supply: 24V 10A DC adapter

  • Speakers: two 6Ω 50W bookshelf speakers + one 8Ω 80W subwoofer

  • Inputs: tested both Bluetooth (5.1) and AUX from a laptop

  • Connected using the provided DC power plug and screw terminals for speakers

Now here are my issues:

  • At medium to high volumes, I get distortion on the subwoofer even though the speakers sound clean

  • Bluetooth pairing works fine at first, but sometimes audio cuts out randomly for a second or two

  • AUX input works, but there’s a noticeable hum when no music is playing

  • The board gets warm after about 30 minutes of use — not hot enough to shut down, but I’m wondering if I need a heatsink or better airflow

What I’ve tried so far:

  • Swapped in a different subwoofer (4Ω 60W) — distortion still happens at higher volume

  • Tried another power supply (19V 6A) — same results, maybe slightly less hum

  • Moved the board away from other electronics to rule out interference

  • Checked wiring polarity and connections — all look fine

My questions:

  1. Is it normal for the subwoofer channel on the ZY-2.1BT to distort earlier than the stereo channels?

  2. Would running it at 12V vs 24V change the noise floor or stability?

  3. Any tricks for reducing the AUX hum — like grounding the input or shielding cables?

  4. Should I consider adding a small heatsink to this board, or is passive cooling usually enough?

Thanks in advance. I’m hoping to clean up the sound and make this stable for daily use.

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    1 reply

    Super User
    September 17, 2025

    you mean this ?

     

    AndrewNeil_1-1758122050321.png

     

     

    That's not an ST product - you need to go to the manufacturer and/or supplier for help with it.

    https://easyelecmodule.com/contact-us/