Eliminating Speaker Buzz

[Jefrpol]

I am the process (in the sense that I would like to begin making purchases) of building a new stereo system. For the time-being, I am using an Aragon amplifier with an Emotiva XDA-2 as dac/pre. They are connected by rca. In this configuration, I have no buzz issues. However, when I replace the Emotiva with an Aragon a/v pre, I get a low level buzz (it sounds like a 60 hz buzz based on listening to a sound file of same). The Emotiva inlet is 2 prong; both Aragons use a three prong.

In an effort to resolve the problem, before buying anything I have tried the following, all with no result: Jensen Line Input Isolator Hum Eliminator; Ebtech Hum X; use of a UPS; connecting the chassis to the ground connection on the back of a Panamax line conditioner; unplugging the cable boxes elsewhere in the house and disconnecting the cable line that outputs from the Fios ONT. I have also changed cables and power cords.

I have tried to isolate the issue as well. The room with my equipment is in the basement and has its own circuit. With all other power off in the house, the buzz remains. Similarly, after renovating my kitchen (the buzz predates this work), a new circuit was installed. With all power off and the equipment plugged into this circuit, the buzz remains. The outlets have been confirmed to be wired properly.

I am likely to look for equipment that allows for balanced connection but I had hoped to eliminate the buzz before buying anything. If need be, I could live with the buzz that is not audible from my sitting position and is unaffected by changes in volume. My concern is that in the move from bookshelf speakers to floorstanders (likely Revel f208) that the buzz will be louder due to the additional drivers. As a general matter, I would obviously prefer to not have this buzz at all.

Any help is appreciated.

 

[Jefrpol]

One last thing: I don't have much equipment to rotate in and out but the buzz persists with a Parasound multi-channel amp in place of the Aragon and with a Woo Audio headphone amp/pre-amp (WA2). A Denon receiver does not cause a buzz in a separate system used for home theater only.

 

[DonH56]

Where exactly did you place the Hum-X and Jensen isolators when you tested them?

What all is connected to each component?

 

[Jefrpol]

Where exactly did you place the Hum-X and Jensen isolators when you tested them?

I tried plugging both the pre-amp and the amplifier into to Hum-X and then both into the line conditioner and directly into the outlet. The Jensen was conected by rca between the preamp and the amplifier.

When neither worked, I returned both.

I should mention that I tried a 2 prong adapter on both the preamp and the amp, though not at the same time. There was no change.

What all is connected to each component?

The buzz exists when it is just the amp and preamp connected. The Emotiva is the exception. (I have a basis Emotiva amp, that has a two prong inlet. That also produces a buzz when connected to the Aragon preamp.) Id din't find the buzz any worse when my my cd player was connected to the preamp, either via toslink or analog though an rca cable.

 

[Jefrpol]

One final (I think) thing to mention: the Aragon combination worked without issue in my last residence. (Though I had a hum from the transformer, that was easily resolved.)

 

[DonH56]

So your setup is a preamp connected only to a power amplifier via RCA cables, with preamp and power amp plugged into the same duplex outlet (or power strip)? Nothing else connected to the preamp or power amp (wall power cords and speakers only)? And using a ground-lift adapter on either component (preamp or power amp) did not fix the problem? And using the Emotiva to drive the power amp results in no hum? The preamp may have a problem...

Does the buzz change with volume?

You could try using the ground-lift plug on the preamp and running a heavy (18 to 12 AWG) wire from the preamp's ground lug to the power amp, perhaps using chassis screws if either or both do not have an explicit ground terminal. But the tests you have done so far point to a defect in the preamp.

 

[somebodyelse]

See the presentation in the first post of this thread - it includes detailed step by step instructions for finding the source of the buzz/hum and fixing it if possible.

 

[GrimSurfer]

This is one of the problems when mixing grounded (pro) and double insulated (consumer) gear. Let me explain...

As you describe it, the issue is almost certainly a ground loop. It is occurring because of a difference in lowest potential between the grounded and double insulated gear.

The circuits in all homes in North America are supposed to be grounded to a single point. This is normally a water pipe or other suitable point of low electrical potential. When engaged, the ground pin on a three pronged plug connects to this single point.

Double insulated circuits work differently. The plug's neutral pin is wired to the panel, which then seeks ground.

So a three pronged plug is directly connected to ground. A double insulated one isn't. Depending on how the home and circuit is wired, and what socket devices are plugged into, mixing grounded and double insulated appliances will result in a rather pernicious ground loop.

I know this doesn't solve your problem but I thought some background into what's really going on will explain why you've had such a difficult time resolving this issue.

The normal "fix" of plugging devices into the same socket often works to resolve loops on like-configured gear. But it often doesn't work when mixing grounded and double insulated gear because they way they find "ground" is fundamentally different.

Please don't use a ground lift. Doing so is dangerous because it defeats the safety devices designed-into your component to conform to code.

Your first step should be to use a circuit checker to confirm that your socket is wired correcty. It's not unusual to find sockets in a home with hot-neutral lines reversed. It happens all the time when owners, who don't know what they are doing, change sockets or do their own wiring.

 

[Jefrpol]

So your setup is a preamp connected only to a power amplifier via RCA cables, with preamp and power amp plugged into the same duplex outlet (or power strip)? Nothing else connected to the preamp or power amp (wall power cords and speakers only)?

Correct. This is all that is required to get the low level buzz. Where they are plugged in made no difference (either duplex, strip or on different circuits).

And using a ground-lift adapter on either component (preamp or power amp) did not fix the problem? And using the Emotiva to drive the power amp results in no hum? The preamp may have a problem...

Correct. I was convinced that it was the preamp until the Woo Audio was connected to the amp and I still had hum. It may be that this is coincidence. I remain somewhat convinced it is the preamp despite not having the issue in my prior residence.

Does the buzz change with volume?

It does not.

You could try using the ground-lift plug on the preamp and running a heavy (18 to 12 AWG) wire from the preamp's ground lug to the power amp, perhaps using chassis screws if either or both do not have an explicit ground terminal. But the tests you have done so far point to a defect in the preamp.

I did connect, with a 14 awg speaker wire, the preamp and amp first just to each other and then also to the ground on the back of my line strip. Nothing changed. I think I also tried that and use the ground-lift plug.

It wouldn't surprise me, after 16 years, that both Aragon units are not what they were. I had only intended to use them as a stop-gap until getting something new. I will have to see about getting something to try

See the presentation in the first post of this thread - it includes detailed step by step instructions for finding the source of the buzz/hum and fixing it if possible.

Thanks for that. I did try the Jensen transformer but that didn't do anything. Perhaps new gear and a balanced connection will resolve the issue or at least mitigate it sufficiently.

Your first step should be to use a circuit checker to confirm that your socket is wired correcty. It's not unusual to find sockets in a home with hot-neutral lines reversed. It happens all the time when owners, who don't know what they are doing, change sockets or do their own wiring.

I wouldn't have expected a ground loop issue between two units that are by the same manufacturer and were specifically intended to be used together and had not previously presented any issues.

As for the wiring, the outlet I tried in the kitchen is brand new, professionally installed and on its own circuit. Even if the one in the basement were incorrectly wired (a socket checker didn't detect an issue and the electrician didn't find it to have been incorrectly wired) I wouldn't imagine the problem to exist in every socket.

It is frustrating but I do appreciate the responses.

 

[GrimSurfer]

FWIW, I had six out of maybe 60 sockets in my home miswired (hot-neutral swapped). One circuit was underwired (gauge too light). Another outdoor socket with a failed (open) GFCI. One circuit with two GFCIs wired in series (which isn't dangerous but demonstrates whoever was doing the work didn't have a clue about the NEC or how GFCIs work.)

That's a 15% error rate in a home in a very nice neighbourhood that had been professionally "inspected".

So the bottom line is that nothing should be taken for granted.

Just went thru a kitchen renovation myself two years ago. Complete tear-out. Big job and had a commercial outfit do the wiring. Took three days but very thorough, including code inspections before (the plan), during (the installation), and after (the clean up). Worth every penny!

 

[Jefrpol]

FWIW.....

I may have to have an electrician come out. It does not appear my socket checker would detect the issue though I would think the electrician who looked at it would have seen the mistake.

 

[GrimSurfer]

The socket checker to use is a three pronged one with several indicator lights: good, ground fault, hot-neutral swapped, open neutral, open ground etc. Available at Home Depot.

 

[RayDunzl]

As you describe it, the issue is almost certainly a ground loop. It is occurring because of a difference in lowest potential between the grounded and double insulated gear.

The circuits in all homes in North America are supposed to be grounded to a single point. This is normally a water pipe or other suitable point of low electrical potential. When engaged, the ground pin on a three pronged plug connects to this single point.

Double insulated circuits work differently. The plug's neutral pin is wired to the panel, which then seeks ground.

So a three pronged plug is directly connected to ground. A double insulated one isn't. Depending on how the home and circuit is wired, and what socket devices are plugged into, mixing grounded and double insulated appliances will result in a rather pernicious ground loop.

I know this doesn't solve your problem but I thought some background into what's really going on will explain why you've had such a difficult time resolving this issue.

The normal "fix" of plugging devices into the same socket often works to resolve loops on like-configured gear. But it often doesn't work when mixing grounded and double insulated gear because they way they find "ground" is fundamentally different.

Please don't use a ground lift. Doing so is dangerous because it defeats the safety devices designed-into your component to conform to code.

Your first step should be to use a circuit checker to confirm that your socket is wired correcty. It's not unusual to find sockets in a home with hot-neutral lines reversed. It happens all the time when owners, who don't know what they are doing, change sockets or do their own wiring.

Nice explanation.

I used to think along some of those lines.

All the gear in my rack has 60Vac on the Neutral, as well as 60Vac of the opposing phase on the "Hot" lead.

Ultimately, all of it is fed from a single wall outlet, at least 100 wire-feet or more, to the electrical panel. The shortest possible path would be 80 feet. The outlet is on a branch that goes all around the room and even includes the overhead 8-tube flourescents in the kitchen. My desktop and all of its attachments is on the same branch.

At the wall, there's a substantial and ugly waveform/voltage drop on the Neutral, depending on the draw of the gear energised at the time, the 100ft 12AWG wire resistance x Current Flow.

The gear is a mix of three-prong and two-prong power cords and wall-warts and USB power among the various boxes there.

I've made no special wiring accomodations with any of the gear. Plug and Play.

No hum.

Well, I did need to provide Earth to a turntable (on loan) and a cheap Behringer P400, but the turntable has a wire for that purpose along with the signal cables, the phono preamp has a thumbscrew to accept it. While fumbling around with all that I did add a jumper to Earth, which may or may not have been needed - I'll have to check that out. The turntable has a two-prong plug, the preamp a two-prong wall-wart.

 

[GrimSurfer]

https://m.ranker.com/list/musicians-electrocuted-on-stage/jessica-defino

Kesha's story seems the most interesting

These things happen when somebody lifts a ground or violates code... except for the haunting issue. That's not mentioned in the NEC.

 

[Jefrpol]

The one I used is: Amprobe ST-102B Socket Tester with GFCI.

I may try swapping out the current duplex outlet for a self-grounding one. Per the presentation linked above: "“Isolated-ground outlets do not connect safety ground to their mounting saddle but only to the green wire and “IG outlets reduce extraneous, and often intermittent, ground noise problems.”

Whether this will have any affect... who knows, but it's a $8 experiment.

 

[GrimSurfer]

That should work just as well as any other to detect a ground fault.

If you have a VOM, remove the interconnects between components. Then, using your VOM's probes, see if you can detect flow between devices. There shouldn't be any if they are on the same socket. There might be some if on different sockets on the same/different circuits.

The uninsulated ground wire should be connected to the metal socket box and the green screw on the back of the socket. The only exception is when the socket box is plastic. It's often a jumbled, tangled mess in there. Sometimes the socket isn't centred or the neutral wire is stripped back too far and is making contact with the box.

Having completed a circuit once on a floating ground (ouch), I'd recommend pulling the main breaker on the house when doing any electrical work. One can never be too careful. 60 mA is all that's needed to mess up cardiac rhythm or worse.

 

[Jefrpol]

I may try swapping out the current duplex outlet for a self-grounding one. Per the presentation linked above: "“Isolated-ground outlets do not connect safety ground to their mounting saddle but only to the green wire and “IG outlets reduce extraneous, and often intermittent, ground noise problems.”

Whether this will have any affect... who knows, but it's a $8 experiment.

In response to myself, the new circuit in the kitchen is wired Romex. Thus, per the slide, is already an isolated ground. Still buzzes there so would seem to point back to the preamp and/or amp.

 

[GrimSurfer]

Is it an Arc Fault circuit?

 

[Jefrpol]

Is it an Arc Fault circuit?

I don't know. I don't think so, but I took a picture.

Incidentally, the green wire that comes out of the top is, I assume, the ground. Before leaving the house, it is resting on two different pipes. Would this cause any issues?

 

[GrimSurfer]

Doesn't look like they are. Typically, an Arc Fault is a retrofit. It is wired in series with the protected circuit. It looks like a GFCI in a box but is marked AFCI.

The reason why it is done this way, according to my electrician, is that the AFCI socket needs to be as close to the panel as possible in order to sense any downstream shorts. They're really sensitive and can trip before an arc occurs because they sense the ion flow just before a spark jumps. For this reason, they don't like being inside the main panel. They're just too sensitive. (In my jurisdiction, no arc fault fitted homes have been lost to electrical fires since it was incorporated into code.). Simple but very effective tech.

In a new build, the AFCI protected circuits have a breaker that looks like this:

I mentioned arc fault because, like GFCIs, they can be electrically noisy.

I can't say with any certainty what's going on with the green wire you mention. The home's main ground wire is normally uninsulated and quite thick... perhaps 6-8 gauge stranded copper. It's thick because it is also intended to shunt a lightning strike or transformer short to ground (besides being the lowest electrical potential for home circuitry).