HELP! low freq hum on the sub

ohskigod
ohskigod Posts: 6,502
edited April 2006 in Subwoofer Hookup & Bass Management
just noticed a low frequency hum on my sub. hums even if i disconnect the subwoofer cable. if i touch the imputs with my finger, the hum diminishes slightly. the volume and crossover settings have no effect on the hum. if i turn the phase control to 0, (all the way to the left), the hum gets louder. if i turn it to 180 degrees, the hum gets much lower in volume (but still there). I changed the power cable with no change. cant be a ground loop since it does it even when disconnected from the sub cable.

please help, this is driving me nuts, do i need a new plate amp?

i use a parts express 250W plate amp (the one without the bass boost i believe) if this helps


desperatly
Lou
Living Room 2 Channel -
Schiit SYS Passive Pre. Jolida CD player. Songbird streamer. California Audio Labs Sigma II DAC, DIY 300as1/a1 Ice modules Class D amp. LSi15 with MM842 woofer upgrade, Nordost Blue Heaven and Unity interconnects.

Upstairs 2 Channel Rig -
Prometheus Ref. TVC passive pre, SAE A-205 Amp, Wiim pro streamer and Topping E50 DAC, California Audio Labs DX1 CD player, Von Schweikert VR3.5 speakers.

Studio Rig - Scarlett 18i20(Gen3) DAW, Mac Mini, Aiyma A07 Max (BridgedX2), Totem Mites
Post edited by ohskigod on
· Share on FacebookShare on Twitter

Comments

  • PolkThug
    PolkThug Posts: 7,532
    edited August 2004
    Sounds like the amp has an issue, if it sits their and hums even without an input.
    Never Forget
    · Share on FacebookShare on Twitter
  • ohskigod
    ohskigod Posts: 6,502
    edited August 2004
    funny thing is, if i jiggle the input jacks, sometimes the sound goes away. wierd. also, if i touch the top of the plate amp, the sound goes away too. ???
    Living Room 2 Channel -
    Schiit SYS Passive Pre. Jolida CD player. Songbird streamer. California Audio Labs Sigma II DAC, DIY 300as1/a1 Ice modules Class D amp. LSi15 with MM842 woofer upgrade, Nordost Blue Heaven and Unity interconnects.

    Upstairs 2 Channel Rig -
    Prometheus Ref. TVC passive pre, SAE A-205 Amp, Wiim pro streamer and Topping E50 DAC, California Audio Labs DX1 CD player, Von Schweikert VR3.5 speakers.

    Studio Rig - Scarlett 18i20(Gen3) DAW, Mac Mini, Aiyma A07 Max (BridgedX2), Totem Mites
    · Share on FacebookShare on Twitter
  • ohskigod
    ohskigod Posts: 6,502
    edited August 2004
    WTF???? sound is gone, jiggled the jacks yesterday as noted below, and today, no noise. oh well, i guess i should be happy.

    my guess now that it is a ground issue since i was able to touch the amp with my finger in some places (on the outside of course) and the sound went away

    friggin wierd!

    at least all is well

    thanx for the help anyway :)
    Living Room 2 Channel -
    Schiit SYS Passive Pre. Jolida CD player. Songbird streamer. California Audio Labs Sigma II DAC, DIY 300as1/a1 Ice modules Class D amp. LSi15 with MM842 woofer upgrade, Nordost Blue Heaven and Unity interconnects.

    Upstairs 2 Channel Rig -
    Prometheus Ref. TVC passive pre, SAE A-205 Amp, Wiim pro streamer and Topping E50 DAC, California Audio Labs DX1 CD player, Von Schweikert VR3.5 speakers.

    Studio Rig - Scarlett 18i20(Gen3) DAW, Mac Mini, Aiyma A07 Max (BridgedX2), Totem Mites
    · Share on FacebookShare on Twitter
  • pare
    pare Posts: 11
    edited April 2006
    Thanks
    I was keeping the subwoofer on the carpeted floor in my apartment. I kept it on a table just to test and its silent now. thats such a relief.
    · Share on FacebookShare on Twitter
  • pare
    pare Posts: 11
    edited April 2006
    Sorry I replied to the wrong thread.
    I noticed a very low hum from my sub and its silent after I put it on a platform instead of on the carpet.
    · Share on FacebookShare on Twitter
  • Zen Dragon
    Zen Dragon Posts: 501
    edited April 2006
    ohskigod wrote:
    WTF???? sound is gone, jiggled the jacks yesterday as noted below, and today, no noise. oh well, i guess i should be happy.

    my guess now that it is a ground issue since i was able to touch the amp with my finger in some places (on the outside of course) and the sound went away
    QUOTE]

    Definitely sounds like a grounding issue. If jiggling the jacks took care of it it may be a bad shield on a cable or on the jack. If it returns check the shield connections on the jacks internally or with a multimeter. Might check the resistance end to end on the low side of the cable. Flex the cable while taking the measurement and watch for changes in the value.
    The Family
    Polk SDA-1C's
    Polk SDA-2
    Polk Monitor 10B's
    Polk LSI-9's
    Polk Monitor 5's
    Polk 5 jr's
    Polk PSW-450 Sub
    Polk CSI40 Center

    Do not one day come to die, and discover you have not lived.
    This is pretty f***ed up right here.
    · Share on FacebookShare on Twitter