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You have a ground loop via the multiple pieces of equipment that you have plugged in. Use unpolarized plugs in all except one pice of equipment (power amp maybe).
 

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I don't think you have a ground loop, I think you have a broken ground, probably in 1 of your cables. Ground loops tend to buzz continually not every 6-8 seconds, but something else in your house might be cycling noise onto the neutral that a badly grounded signal path could pick up on. Try changing cables and if you have a DVM, check continuity.
 

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Two things that will help remove ground noise, if not completely eliminate is 1) Get a couple of those old-school 2-to-3 prong plug adapters. These effectively lift the house power ground from anything plugged into it without changing any house wiring or having to cut the ground pin off your 3 prong plugs. Many appliances and power supplies just dump extra voltage right into the common house ground causing excessive ground ckt noise. Start with your source components first then also try on amp/s. The adapter are only $1-$2 each and won't limit current delivery at all. And #2) Get a good (real) A/V power conditioner for your source components. There's often good deal on CL. This will costs more but will also certainly help eliminate ground noise. Skip the power strips that claim to have noise filtering. Then #3) Combine both >> put the 2-3 prong adapter on the plug of the power conditioner that all your source components are plugged into.
 

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I thought i would add a few extraneous thoughts for consideration.

Although single wire unbalanced interconnects are inferior to three wire balanced interconnects in their ability to transfer cleaner signals over longer distances and usually neither are problematic in small home theaters.

Problems can occur when using all single wire unbalanced interconnects throughout the system and later introducing a single pair of three wire balanced interconnects is potentially problematic. While the signal and chase ground wires remain connected throughout the signal path, the signal ground lead and negative ground leads and their effect on components as they are connected only at one end might be looked at.

The dislocated signal ground lead and negative ground leads will become susceptible to emi and rfi noise as each are in effect (one potentially two connected only at the component) become antenna. Say for instance the computer fan is close enough to cause electromagnetic interference..., i think you all can finish my thoughts here.

Most good computer sound cards compensate for fan (resonant frequency) noise but if your interconnects and speaker wires are problematic and pass too close you may receive extraneous unwanted signals and other interference.

a Clean Ground is critical as is a clean signal transfer.

I hope you get this figured out - sounds like you've got part of the problem identified.
 

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Discussion Starter #28
Two things that will help remove ground noise, if not completely eliminate is 1) Get a couple of those old-school 2-to-3 prong plug adapters. These effectively lift the house power ground from anything plugged into it without changing any house wiring or having to cut the ground pin off your 3 prong plugs. Many appliances and power supplies just dump extra voltage right into the common house ground causing excessive ground ckt noise. Start with your source components first then also try on amp/s. The adapter are only $1-$2 each and won't limit current delivery at all. And #2) Get a good (real) A/V power conditioner for your source compmonents. There's often good deal on CL. This will costs more but will also certainly help eliminate ground noise. Skip the power strips that claim to have noise filtering. Then #3) Combine both >> put the 2-3 prong adapter on the plug of the power conditioner that all your source components are plugged into.
So for any equipment with 2 prong plugs, buy the 3 prong adapters? That’s easy.

Good info here guys, thank you. At least for the moment the issue has been partially resolved. The buzz exists but only if my ear is up against the speaker.
 

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Discussion Starter #29
I don't think you have a ground loop, I think you have a broken ground, probably in 1 of your cables. Ground loops tend to buzz continually not every 6-8 seconds, but something else in your house might be cycling noise onto the neutral that a badly grounded signal path could pick up on. Try changing cables and if you have a DVM, check continuity.
I’ll be yanking my system out in a few months for a remodel, so I’ll grab some new RCA cables before reconnecting. Will the premium ones from mono price (gold plated) be sufficient? What’s DVM?
 

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Discussion Starter #30
I thought i would add a few extraneous thoughts for consideration.

Although single wire unbalanced interconnects are inferior to three wire balanced interconnects in their ability to transfer cleaner signals over longer distances and usually neither are problematic in small home theaters.

Problems can occur when using all single wire unbalanced interconnects throughout the system and later introducing a single pair of three wire balanced interconnects is potentially problematic. While the signal and chase ground wires remain connected throughout the signal path, the signal ground lead and negative ground leads and their effect on components as they are connected only at one end might be looked at.

The dislocated signal ground lead and negative ground leads will become susceptible to emi and rfi noise as each are in effect (one potentially two connected only at the component) become antenna. Say for instance the computer fan is close enough to cause electromagnetic interference..., i think you all can finish my thoughts here.

Most good computer sound cards compensate for fan (resonant frequency) noise but if your interconnects and speaker wires are problematic and pass too close you may receive extraneous unwanted signals and other interference.

a Clean Ground is critical as is a clean signal transfer.

I hope you get this figured out - sounds like you've got part of the problem identified.
So should I just stick with all unbalanced cables then? I do have I believe one set of balanced cables yet going from my DAC to preamp.
 

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Sorry to take so long to respond. It wasn't long ago any answer to your question would inspire controversy and a long heated discussion.

i'll try to avoid the controversy by suggesting there are XLR/RCA and/or RCA/XLR adapters available.

Neutrix is a decent product: https://www.alliedelec.com/product/neutrik/na2fpmf/70548691/?&mkwid=siIB6CgwX&pcrid=30980760979&pkw=&pmt=&gclid=EAIaIQobChMIqImIi5Cl4AIVzICfCh2qnwBwEAQYAiABEgKVY_D_BwE&gclsrc=aw.ds

I wrote my comment in the early AM hours sorry a bit convoluted and absent description - no proof read...

My understanding of circuit buzz is mostly a result of ground issues and voltage drop/additive issues (e.g. using multiple AC receptacles in a singular AV circuit and/or multiple amps in a singular circuit). Additionally, personally i look for circuit continuity including EM integrity. What I mean is, in every electric circuit, electricity in motion is accompanied with an electromag wave that extends well beyond the wire insulation sheath, right..., possible reason for some acceptable low S/N ratios common common to every electric component?

..., i am not suggesting you continue a balanced interconnect with adapters rather i would buy a furutech unbalanced interconnect for the sake of continuity.

However, a further consideration might be a very expensive "Ground Boost" from Synergistic Research...., or additional diode rectifier somewhere

You know..., a simple voltage checker (crossed AC line)with a $10 GB GFCI checker might be revealing. Maybe check component AC out lines as well

I hope you find something.
 

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Discussion Starter #32
Sorry to take so long to respond. It wasn't long ago any answer to your question would inspire controversy and a long heated discussion.

i'll try to avoid the controversy by suggesting there are XLR/RCA and/or RCA/XLR adapters available.

Neutrix is a decent product: https://www.alliedelec.com/product/neutrik/na2fpmf/70548691/?&mkwid=siIB6CgwX&pcrid=30980760979&pkw=&pmt=&gclid=EAIaIQobChMIqImIi5Cl4AIVzICfCh2qnwBwEAQYAiABEgKVY_D_BwE&gclsrc=aw.ds

I wrote my comment in the early AM hours sorry a bit convoluted and absent description - no proof read...

My understanding of circuit buzz is mostly a result of ground issues and voltage drop/additive issues (e.g. using multiple AC receptacles in a singular AV circuit and/or multiple amps in a singular circuit). Additionally, personally i look for circuit continuity including EM integrity. What I mean is, in every electric circuit, electricity in motion is accompanied with an electromag wave that extends well beyond the wire insulation sheath, right..., possible reason for some acceptable low S/N ratios common common to every electric component?

..., i am not suggesting you continue a balanced interconnect with adapters rather i would buy a furutech unbalanced interconnect for the sake of continuity.

However, a further consideration might be a very expensive "Ground Boost" from Synergistic Research...., or additional diode rectifier somewhere

You know..., a simple voltage checker (crossed AC line)with a $10 GB GFCI checker might be revealing. Maybe check component AC out lines as well

I hope you find something.
Thanks for the reply! After more digging and trial and error, it seems as if the stereo pair of RCA wires I ran from my DAC in my main setup to another stereo in our bedroom was causing the hum/static sounds. By unplugging it, problem solved!
 

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Without looking back thru comments - how/where do you switch from the AVR to your P7. All handled internally in the AVR? Do you power down the P7 when not in use and visa/versa? Where is the DAC located... in your 2 channel sys...
 
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