Possible ground loop or power conditioner issue

gmcman

I'm not sure if it's a ground loop, but I've seemed to narrow down the slight buzz in my speakers to my Panamax M5400 EX and my cable box. I have the panamax in my stand above the power amp (B&K 200.2), not directly sitting on the amp, but on the shelf above. I get a faint buzz from the speakers when the panamax is plugged in with nothing connected to it, I get more noise when I plug in the cable box.

The cable box is the Fios Quantum DVR and uses a DC power supply, the DC power supply is what's plugged into the panamax, noise is unchanged with or without the coax connected to the DVR.

I've tried to unplug components one at a time from the panamax with no change except for when I unplug the DVR. The buzz is less with the DVR unplugged but completely goes away with the panamax unplugged from the wall.

I've tried a cheater plug on the amp, the panamax, different outlets and different circuits, the only thing that removes the buzz completely, is unplugging the panamax, turning it off doesn't change the buzz, only unplugging it from a power source.

So the only thing I haven't tried is changing the power cord to the panamax or relocate it, or a different power distribution device,

Could the panamax create interference that could be picked up by the amp?

I went back to the stock power cord on the panamax which is quite robust but could possibly be the issue, but why with only the panamax being powered up would it cause a buzz in the speakers?

tonyb

Maybe it's time to move on to a PS Audio conditioner.

So you mean the Panamax creates a buzz, because the amp is connected to it ? How can you hear it through the speakers if nothing is connected through it ?

Try taking a piece of wire and going from a screw on the case of the Panamax to an outlet screw. A cold water pipe if close by would work also.

gmcman

tonyb wrote: »

So you mean the Panamax creates a buzz, because the amp is connected to it ? How can you hear it through the speakers if nothing is connected through it?

No, nothing is connected to the panamax, it was only on the shelf plugged into the wall.

Amp, Preamp, and cd player are plugged into the wall. The Panamax is above the amp, on a shelf about 4" above.

When I unplug the panamax, the noise goes away.

PS audio is looking good.

tonyb

Wait man, are you saying that simply plugging in the Panamax to the wall, with nothing plugged into the Panamax, creates a buzz in the whole electrical circuit your other gear is on ?

Do you have another small system somewhere in the house you can try that panamax on to confirm that ? Otherwise it may be toast, or that electrical outlet is garbage and you should change to a hospital grade from Home depot.

I have one of PS Audio's lower lines, looks like a huge plug strip, but it has out performed Monsters top PC at every level. I have plugged into this my TV, receiver, pre amp, dac, Blu-ray player, cable box and the cable itself go through it, Sonos, and my system is quiet as a church mouse. Picked it up for 3 bones and change and it's been the best PC I've had to date.

gmcman

tonyb wrote: »

Wait man, are you saying that simply plugging in the Panamax to the wall, with nothing plugged into the Panamax, creates a buzz in the whole electrical circuit your other gear is on ?

Yes indeed.

The outlet I had the panamax in, was the same I have the amp plugged in to and it's dead silent.

Possibly generating some type of electrical or magnetic interference, I will relocate it and see if that changes anything later today.

Definitely crazy, never thought it would be a cause of a buzz.

Easy Runnin

First off, I have no idea what I'm talking about. But since you have Fios and you think it might be your cable box, could it also be the optical network terminal? Have you tried disconnection both of them?

gmcman

I haven't tried the network box, but there is a louder buzz with the dvr plugged into the outlet.

But that's a seperate issue though, the panamax is providing noise with nothing attached to it.

F1nut

EMI

lightman1

F1nut wrote: »

EMI

Yup. Time to break out the lead blanket and toss over the Panamax.

gmcman

I have to shove off to work, I'll add more to this later but when I pulled the panamax from the stand and placed it on the floor about 3' in front of the amp, the noise was pretty much gone.

Here's a clip of what I'm hearing at the speaker.

https://www.youtube.com/watch?v=MNFFj-YwDR4&feature=youtu.be

kharp1

tonyb wrote: »

Maybe it's time to move on to a PS Audio conditioner

I'm leaning very heavily to the Power Station 3 or 5. I like the idea of regenerated power.

gmcman

Looking further into this speaker buzz from my cable box... So my current setup is:

Verizon Fios to TV via HDMI> TV to Denon AVR via toslink> AVR to VTL 2.5 HT Bypass circuit via MIT AVT-3 RCA> VTL 2.5 to B&K 200.2 via Shotgun S1 RCA. Also the CD to VTL 2.5 is via S1 RCA as well.

The TV, Fios, AVR, X-Box1, Turntable, phono stage, go into the power conditioner, rest is in the wall.

Noise is same with or without cable coax connected.

Not sure if there is a ground loop, or where it would be...any basic steps to take to check for this?

gmcman

With the Fios issue set aside, this is from the VTL 2.5 preamp.

https://youtu.be/5D1v3YGvrp0

gmcman

So I had a chance to look into the situation a little more today.

I have a 2-gang box at one end of the HT/stereo setup, and one 1-gang box at the other end. I have been using both, but the 2-gang box is on my main panel, the 1-gang box is on my sub panel.

Inside the 2-gang box is two separate romex leads, one seems to be the feed, the other may be powering something else, both outlets are connected with jumpers as the 2nd outlet provides the feed for the currently unknown device.

Could be my issue but I have some porter port outlets I will try so at least I can get rid of the contractor outlets.

tonyb

If the problem wasn't there before, chances are it doesn't lay with the gang boxes. To me anyway, that sound tells me something is amiss electrically, not a ground loop. When you plug everything directly into the wall, do you still get the same buzz ? Take the Panamax completely out of the loop.

If that doesn't work, take the amp out of the loop and just use the avr.....see what that does.

kharp1

I'm not sure I'm following your set up with power from the panel, but, if I'm following correctly it sounds like you have two seperate circuits feeding items from the same system, and that's a no-no. Your difference of potential to ground will obviously vary from seperate circuits which can induce hum.

Put everything on the same circuit and start plugging in one component at a time until the hum appears.

rpf65

Sounds like both of you plugs are connected to the same breaker. If this is standard household wiring, there is, more than likely at least 2 other potential loads on that circuit. Could be other plug(s), lights, or combination.

If it were me, I would start by diconnecting the sub and amp from the plug, not just turning the power off. Then test the system. If hum still present, would disconnect the AVR from the Panamax, and unplug it from the plug. Run just the AVR, maybe an FM station, and see if hum is present. If hum is present, I would then start disconnecting component in/outputs one at a time.

tonyb

If it were me...I'd tell the wife something bit the dust and I have to go buy a new one. Pick which component you want a new one of. lol You didn't hear that idea from me though.

gmcman

Ha...she's actually pretty cool when it comes to the hobbies. Either this weekend or the next, I'm going to run another dedicated circuit to that end of the room, should be able to narrow it down after that.