New Parasound 2250 v2 Amp - Hum

Bad1550
Bad1550 Posts: 10
in 2 Channel Audio
Just picked up a Parasound 2250 v2 amp to drive my Polk LSIM 707s. I have it connected to the Onkto TX-NR838 preout and my Cable TV

I am getting hum and do not know what to do as I am a newbie to amps. I have the Center, 2 surrounds and 2 heights connected to the Onkyo.

Any help to finally hear the 707s shine and without hum would be greatly appreciated. Ive attached a pic of Parasound Amp and Onkyo connection

Thanks,

Bobyr4jzw51gik5.jpg
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Comments

  • tonyb
    tonyb Posts: 32,963
    Could be a ground loop....but your cables seem on the entry level side too so you may want to consider better quality cables. Do you have the amp in bridged mode ? If so, take it off.

    Get yourself a 2 buck cheater plug at any hardware store. A 3 prong to 2 prong adapter and see if that helps with the hum.
    HT SYSTEM-
    Sony 850c 4k
    Pioneer elite vhx 21
    Sony 4k BRP
    SVS SB-2000
    Polk Sig. 20's
    Polk FX500 surrounds

    Cables-
    Acoustic zen Satori speaker cables
    Acoustic zen Matrix 2 IC's
    Wireworld eclipse 7 ic's
    Audio metallurgy ga-o digital cable

    Kitchen

    Sonos zp90
    Grant Fidelity tube dac
    B&k 1420
    lsi 9's
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  • Bad1550
    Bad1550 Posts: 10
    I do not have the bridge mode enabled
    I will pickup an adapter prong and hopefully that will solve the hum

    Thanks
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  • Bad1550
    Bad1550 Posts: 10
    Picked up this Ground Loop Isolator from RadioShack and resolved the problem

    http://www.radioshack.com/ground-loop-isolator/2700054.html#q=Ground+loop&start=1
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  • jeremymarcinko
    jeremymarcinko Posts: 3,785
    I wouldn't want that in my signal chain. Take Tony's advice get the two/three prong adapter.
    Oh, Listen here mister. We got no way of understandin' this world. But we got as much sense of this bird flyin in the sky. Now there is a lot that bird don't know, but it don't change the fact that the world is happening to him all the same. What I am tryin to say is, is that the course of your life, well its changing, and you don't even see it- Forest Bondurant
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  • Bad1550
    Bad1550 Posts: 10
    jeremymarcinko wrote: »
    I wouldn't want that in my signal chain. Take Tony's advice get the two/three prong adapter.

    Just replaced the isolator with the two/three prong adapter and it works great.
    Will return the isolator.

    Thanks again!
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  • F1nut
    F1nut Posts: 50,554
    edited January 2015
    The ground issue is with your cable service. Tell them their equipment needs a proper ground. The cheater plug should be a temporary fix only.

    You also need a serious speaker cable upgrade.



    Political Correctness'.........defined

    "A doctrine fostered by a delusional, illogical minority and rabidly promoted by an unscrupulous mainstream media, which holds forth the proposition that it is entirely possible to pick up a t-u-r-d by the clean end."

    President of Club Polk

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  • tonyb
    tonyb Posts: 32,963
    Cable companies are notorious for bad grounding and cheap equipment. You can go to any Home depot and buy a copper rod to hammer in the ground near where your service comes in the building. Then just run a wire to a clamp on the rod and to a signal splitter if you have one installed or directly to the box.

    Cheap cables as Jessie suggests too can also be part of a ground loop problem as well as cheap construction grade outlets. The very least install some hospital grade wall outlets for your audio....also available at any Home Depot.
    HT SYSTEM-
    Sony 850c 4k
    Pioneer elite vhx 21
    Sony 4k BRP
    SVS SB-2000
    Polk Sig. 20's
    Polk FX500 surrounds

    Cables-
    Acoustic zen Satori speaker cables
    Acoustic zen Matrix 2 IC's
    Wireworld eclipse 7 ic's
    Audio metallurgy ga-o digital cable

    Kitchen

    Sonos zp90
    Grant Fidelity tube dac
    B&k 1420
    lsi 9's
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  • Bad1550
    Bad1550 Posts: 10
    I appreciate all of your help!
    Thanks

    Bob
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  • steveinaz
    steveinaz Posts: 19,538
    Another "work-around" (if available) is to go toslink from your cable box to your DAC.
    Source: Bluesound Node 2i - Preamp/DAC: Benchmark DAC2 DX - Amp: Parasound Halo A21 - Speakers: MartinLogan Motion 60XTi - Shop Rig: Yamaha A-S501 Integrated - Shop Spkrs: Elac Debut 2.0 B5.2
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  • skrol
    skrol Posts: 3,375
    A bit of an old post but I recently had a hum issue when I had my HCA-1000A on the bench. It was plugged into a separate outlet than my preamp and I had a long, cheap interconnect. Connecting them to the same outlet solved the hum.
    Stan

    Main 2ch:
    Polk LSi15 (DB840 upgrade), Parasound: P/LD-1100, HCA-1000A; Denon: DVD-2910, DRM-800A; Benchmark DAC1, Monster HTS3600-MKII, Grado SR-225i; Technics SL-J2, Parasound PPH-100.

    HT:
    Marantz SR7010, Polk: RTA11TL (RDO198-1, XO and Damping Upgrades), S4, CS250, PSW110 , Marantz UD5005, Pioneer PL-530, Panasonic TC-P42S60

    Other stuff:
    Denon: DRA-835R, AVR-888, DCD-660, DRM-700A, DRR-780; Polk: S8, Monitor 5A, 5B, TSi100, RM7, PSW10 (DXi104 upgrade); Pioneer: CT-6R; Onkyo CP-1046F; Ortofon OM5E, Marantz: PM5004, CD5004, CDR-615; Parasound C/PT-600, HCA-800ii, Sony CDP-650ESD, Technics SA 5070, B&W DM601
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