A frustrating audible hum in my setup, please help!

Trying to eliminate a very annoying 120 hz (I think, seems higher than your typical 60 hz hum) buzzing sound coming through my setup. I’ve tried tons of things, new surge protectors, different outlets, hum x, etc. it’s a buzz that come on every 6-8 seconds, buzzes for a few then goes off, never stopping. It does disappear on occasion and other times it’s less pronounced. Its not the amp, ruled that out long ago.

My setup is very complex.
Ascend speaks obviously;)
Yamaha cx5000 pre
Parasound amp a21
Parasound pre p7
Behringer fbd
Dual subs Rythmik
Custom built pc for streaming movies and Jriver music with 200 watt external power supply (hd Plex)
Schiit dac
Directv box
Sony ps3
Outlaw 7 ch amp for surrounds and zone speakers

I’ve tried unplugging cables many times and can’t seem to locate the root of the problem.

Any suggestions on where to begin?
Thanks.

Recent smart meter install?

https://www.securityweek.com/smart-m...me-electronics

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Originally Posted by rjkruk

Recent smart meter install?

https://www.securityweek.com/smart-m...me-electronics

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Not that I am aware of.

did you try moving the cable box/disconnecting?
any dimmer switches?

Live near any radar or other transmission systems?

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Originally Posted by racrawford65

did you try moving the cable box/disconnecting?
any dimmer switches?

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Move directv box where?
There may be a dimmer on that circuit, I’ll check.

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Originally Posted by jimb

Live near any radar or other transmission systems?

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Nope, pretty rural by me.

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Originally Posted by merrymaid520

Move directv box where?
There may be a dimmer on that circuit, I’ll check.

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cable box - disconnect from your system entirely and away from other components. I've seen on other forums (don't recall which) that in some cases cable boxes were the source of noise.

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Originally Posted by racrawford65

cable box - disconnect from your system entirely and away from other components. I've seen on other forums (don't recall which) that in some cases cable boxes were the source of noise.

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Well I unplugged the satellite feed (rg6 cable) coming into the directv box and unplugged it’s power source and nothing changed. I also confirmed the outlet that all my equipment is plugged into is a dedicated one with nothing else on it. Still that darn hum/buzz.

Did this just start recently and have you added any new electric / electronics lately?
Your or neighbors put in any electric fence? Power and signal cables for audio separated?
I would check with your electric company and ask if they have made any changes.

Also, is there any interference on a landline phone? Either wired or cordless.

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Originally Posted by rjkruk

Did this just start recently and have you added any new electric / electronics lately?
Your or neighbors put in any electric fence? Power and signal cables for audio separated?
I would check with your electric company and ask if they have made any changes.

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I did switch out a power supply recently for my pc but the buzz existed before and after. No electric fences I’m aware of plus out lots here are 1.5 acres, so no close neighbors. I’ve not separated my cables because of the way my AV stand is. Just way too many wires all over the place.

One discovery which I hope is relevant. So my Parasound P7 has HT bypass which I of course use in my setup. When it’s in bypass, meaning I’m using the Yamaha CX-A5000 for volume, sources, etc, the buzz is audible like I’ve described. As soon as I switch the Parasound P7 to any source coming into it other than HT bypass, the buzz disappears completely. So for example, if I switch the P7 to my music input coming from my Schiit DAC, the buzz is gone!

Does this help narrow things down?

WELL. NOW you tell us. If I understand you correctly, and the input to the Yamaha is not changed (same cable from the P7 to the same input on the Yamaha), then the P7 is bad, or there's a grounding issue "through" it. To be sure, can you sketch up a little diagram of the sources, the P7, the Yamaha and the interconnections?

Are the Parasound and Yamaha on the same circuit?

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Originally Posted by rjkruk

Also, is there any interference on a landline phone? Either wired or cordless.

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No landline phones in the house

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Originally Posted by rjkruk

Are the Parasound and Yamaha on the same circuit?

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Yes

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Originally Posted by jimb

WELL. NOW you tell us. If I understand you correctly, and the input to the Yamaha is not changed (same cable from the P7 to the same input on the Yamaha), then the P7 is bad, or there's a grounding issue "through" it. To be sure, can you sketch up a little diagram of the sources, the P7, the Yamaha and the interconnections?

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Sorry:)
Yes, the buzzing only disappears when a source on the p7 is selected. When it’s in HT bypass meaning my Yamaha is acting as source and going through the P7 is when the buzzing happens. I didn’t mess with any cables.

Hoping the p7 is ok! The buzz only comes through on One speaker. I’ll do my best to create a diagram

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Originally Posted by merrymaid520

Sorry:)
Yes, the buzzing only disappears when a source on the p7 is selected. When it’s in HT bypass meaning my Yamaha is acting as source and going through the P7 is when the buzzing happens. I didn’t mess with any cables.

Hoping the p7 is ok! The buzz only comes through on One speaker. I’ll do my best to create a diagram

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I think you just need to give up and send me your equipment. :D

For the side that is humming, swap the input cables into the P7 to see if the hum follows the cable.

Also if the P7 is set to HT Bypass, and the Yamaha is off, is the hum still present?

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Originally Posted by curtis

I think you just need to give up and send me your equipment. :D

For the side that is humming, swap the input cables into the P7 to see if the hum follows the cable.

Also if the P7 is set to HT Bypass, and the Yamaha is off, is the hum still present?

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You dont want a buzzing preamp do you:)

I will try this when I return home and report back.

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Originally Posted by jimb

WELL. NOW you tell us. If I understand you correctly, and the input to the Yamaha is not changed (same cable from the P7 to the same input on the Yamaha), then the P7 is bad, or there's a grounding issue "through" it. To be sure, can you sketch up a little diagram of the sources, the P7, the Yamaha and the interconnections?

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Diagram.....

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Originally Posted by curtis

I think you just need to give up and send me your equipment. :D

For the side that is humming, swap the input cables into the P7 to see if the hum follows the cable.

Also if the P7 is set to HT Bypass, and the Yamaha is off, is the hum still present?

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So I swapped the preouts from the Yamaha into the P7 and the hum doesn’t seem to change much if at all. I also turned off the Yamaha while the leaving everything else on and p7 in HT bypass and hum still exists, no change.
Once I unplug those interconnects coming out of the Yamaha into the p7, the hum disappears.

So I think I fixed it! The Parasound A21 amp has two options for Input, balanced and unbalanced connections. I removed my balanced XLR cables from it and the p7, and replaced the pair with good old RCA cables, flipped the switch on back of the A21 and guess what, the buzz is nearly inaudible!!

I have no clue why this fixed it but so far so good:)

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Originally Posted by merrymaid520

So I think I fixed it! The Parasound A21 amp has two options for Input, balanced and unbalanced connections. I removed my balanced XLR cables from it and the p7, and replaced the pair with good old RCA cables, flipped the switch on back of the A21 and guess what, the buzz is nearly inaudible!!

I have no clue why this fixed it but so far so good:)

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That's good, but it does seem like there is a problem somewhere.

Something not good with the XLR cables, maybe.

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Originally Posted by curtis

That's good, but it does seem like there is a problem somewhere.

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It could be a bad cable perhaps? I guess as long as the issue (buzz) is gone, I am happy with that! I will be doing a first floor remodel this spring so the entire setup will be packed up and moved out for a bit. Maybe upon its return, the problem will cease to exist.

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Originally Posted by jimb

Something not good with the XLR cables, maybe.

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Might be! They are just basic XLR cables, nothing fancy.