Sonic Reaper Posted April 19, 2006 Share Posted April 19, 2006 The Anthem P2 amp is connected via 3 foot XLR interconnect Raymond cables to almost new Anthem AVM 30 preprocessor. When the amp is running alone the hum does not even register on the Radio SPL meter. When I power up the AVM 30 after powering up the amp with no audio signal coming from the AVM30 (e.g. CD, DVD, radio, VCR, tape or TV is not sending any signal) I hear a 57db hum. Does anyone have any suggestions on reducing the 57db hum from my new Anthem P2 amp? Do I need to separate the amp futher from the AVM30? The most convenient place for the amp is currently on the subwoofer and I have read somewhere on this forum that the configuration I currently use for my Cornwalls and dual subwoofers is optimal when the Cornwalls are placed as closer to the corners of the room than the subwoofers to boost the bass frequencies from the Cornwalls. Will I have to sacrifice optimal placement of my Cornwalls and subwoofer to eliminate this hum? Replace XLR cables? Will the hum be eliminated if I run power to the P2 amp via the Monster Power conditioner instead of a separate outlet (the P2 amp uses a two prong power connector)? Quote Link to comment Share on other sites More sharing options...
steamer Posted April 19, 2006 Share Posted April 19, 2006 Hello, Sounds like a ground loop issue.First get your wires straightened out ie.separate signal wires and power cords.Have you tried a different placement for the amp just to see if it reduces the hum?Also you can turn off power of one auxillary component at a time to see if it goes away.Basicly try anything you can think of when it comes to wire orientation. Greg Quote Link to comment Share on other sites More sharing options...
Sonic Reaper Posted April 20, 2006 Author Share Posted April 20, 2006 I tried running the power for the Anthem P2 amp through a spare outlet on the Monster Power conditioner and was not successful in eliminating the hum. I found some 15 foot Mogami XLR cables I will try next instead of the far more expensive Raymond XLR interconnect cables. If that doesn't work, I will try a spare dual channel EBTech Hum Eliminator with 1/4" TRS jacks I found. I will have to run two sets of interconnect cables to it with a1/4 " connector on one end and male/female XLR connector on other end. Quote Link to comment Share on other sites More sharing options...
Sonic Reaper Posted April 20, 2006 Author Share Posted April 20, 2006 The two 15 foot Mogami XLR cables worked! I was surprised to find I will not be able to use my 6 new Raymond XLR interconnect cables! Since the 3 foot long Raymond cables were new I suspect that the length of the XLR cable might have had an influence on this hum. I will try to experiment with the four other Raymond XLR cables to verify I had not selected the two bad Raymond cables from the set of 6. Quote Link to comment Share on other sites More sharing options...
DrWho Posted April 20, 2006 Share Posted April 20, 2006 Length of the cable should not make a difference. It sounds to me like one of your cables had a bad shield/ground. Quote Link to comment Share on other sites More sharing options...
steamer Posted April 20, 2006 Share Posted April 20, 2006 Length of the cable should not make a difference. It sounds to me like one of your cables had a bad shield/ground. I agree with Mike,either that or cables were to close to something.Generaly xlr's are disigned for long runs and low noise/interference.Glad you solved the problem. Greg Quote Link to comment Share on other sites More sharing options...
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