AC Power Question

Discussion in 'Archived Threads 2001-2004' started by MikeTz, Mar 10, 2003.

  1. MikeTz

    MikeTz Stunt Coordinator

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    I have noticed recently that more and more components are coming with two prong AC power connectors to eliminate ground loop issues. Since there is substantial discussion about after market power cords and electrical noise in this forum, I wonder if this trend is being considered. Seems like an expensive power cord with layers of shielding would be nullified by a two prong power connector because one side of the shield would not be terminated to ground. Its been twenty years since my last transmission line class but I think an unterminated shield acts more like an antenna than a shield. Can anyone comment on two prong AC outlets for Home Theater equipment and their effect on cables and noise?

    Also, can someone tell me how the manufacturers of equipment with two prong AC connectors are grounding the component chassis?
     
  2. Brian OK

    Brian OK Supporting Actor

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    Mike,

    seems to me that the two prong IEC (yes these are listed as IEC connectors)...

    http://www.audioasylum.com/audio/twe...ges/43709.html

    consumer devices are not grounded at the component chassis end.
    Using a DIY power cord/aftermarket PC, shielded or not, which is grounded at the AC plug end only would act to drain EMI/RF to house ground. Thus no antenna effect to introduce/propogate noise into the audio chain. One should use an IEC 2-prong to 3 prong adapter (Harmonic Tech, VansEvers, and dedicatedaudio.com, offer such devices, the dedicatedaudio being cryo'd), and make certain that the power cords drain wire/shield is ONLY terminated at the AC ground.
    IME, no noise from my Panny DVD player with my dedicatedaudio 2- prong adapter to a DIY Belden 83802 with drain shield terminated at the AC plug only. I use a Pass&Seymour 4781.0100 IEC and a cryo'd Hubbell 8215C AC plug in between the 83802.

    I agree that too many consumer level components (DVD,CDP, mostly) are purposely under-engineered to meet a price point and can act as EMI/RF "amplifiers" in many instances. Great for waffle makers, not good for audio/video.

    BOK

    PS- here is the HT 2 prong to 3 prong adapter http://www.harmonictech.com/video_dvd_adapt.htm

    and here is the dedicatedaudio adapter (I have used both, and have the HT one for sale for $40. shipped (shameful plug, but in perfect condition, and broken-in;^)...
    http://cgi.audiogon.com/cgi-bin/cl.p...572&class&3&4&

    The HT adapter is more flexible for tight fits... the dedicated is close and neat to the component. Both work nicely.
     
  3. MikeTz

    MikeTz Stunt Coordinator

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    Thanks Brian. I hadn't thought about a three to two conductor IEC adapter, that's a good idea.

    MT
     

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