I have some old speakers in the house that I wanted to test. So instead of messing with the real stereo unit from the 80s, I bought a $30 stereo from Amazon, and new speaker wire.

The speakers sound okay, but there’s a hum coming from them all the time. Even with the stereo volume knob turned all the way down. Is this normal for stereo systems and I just haven’t noticed?

  • sem@piefed.blahaj.zoneOPEnglish
    2·
    1 day ago

    They are AR something from the 70s or 80s (?). They might have been built from a kit. I’ll update when I get home.

    I’ll look for a ground conntector on the chassis.

    I have other speakers in the house, which connect to a whole home stereo system with wiring in the walls, which have a very very slight hum at 0 volume, compared to these. That may be the whole house being slightly ungrounded? But it is different from my test setup, which has a noticeable hum.

    This “test” setup is on top of the dining room table with the stereo plugged into a wall outlet via an extension cord. About 10ft each of 16 gauge twisted wire speaker cable connects the stereo to both the L and R speaker.

    The stereo is this one: Daakro AK45 Stereo Audio Amplifier,300W Home 2 Channel Wireless Bluetooth 5.0 Power Amplifier System, Home Amplifiers FM Radio, USB, SD Card, with Remote Control Home Theater Audio Stereo System : Electronics

    https://www.amazon.com/gp/aw/d/B0BX8TGZZF

    Thank you for sharing your expertise!

    • bridgeenjoyer@sh.itjust.works
      1·
      2 days ago

      I see! OK looking at that unit, it doesn’t appear to have a separate ground. Although it does seem to be a low build quality which could be causing your issue. If you wanted you could try running it on DC power since that would be filtered, it could fix your issue.

      Are the in wall speakers on a different amplifier?

      I am leaning toward it being your house wiring or the amplifier. The speakers and their wiring are likely fine.

      • sem@piefed.blahaj.zoneOPEnglish
        2·
        1 day ago

        Yes the house speakers (almost imperceptible hum, with the wires in the wall) are amplified by an Onkyo Tx-8011, which goes through a Niles audio HDS-6 high definition speaker selection system, with the protection toggle always engaged.

        For protection, it says:

        Disengaged:
        1-2 8 ohm
        1 4 ohm

        Engaged:
        3-6 8 ohm
        2-6 4 ohm

        But honestly I don’t have the users manual and I don’t know what it means.

        Back to the test setup (with the louder hum; speaker wire NOT in the walls, just draped over the dining room table), the speakers are AR18s, U028144. The 2 pronged plug is NOT polarized. I’ll look for a DC power supply and see how that goes.