Can't tell,if my house is properly grounded


Hey guys, I have a low level hi/low buzz that is coming through my speakers, not dependent on the integrated tube amps volume. It is amplified when I turn on my Parasound JC3+ Phono preamp, but only slightly. I have the power cords going to the same outlet. I tried running their power through my Furman Elite Power conditioner but that changed nothing. I ran an independent ground wire and checked all the components in various configurations to no avail. I disconnected all the tv cable to make sure it wasn't coming from there and that solved nothing either. I turned off everything in the house I could' no change. I checked my ground outside at the rod and it is all solidly connected, however the depth of the rod is unknown.

any other thoughts before I call out an electrician?
last_lemming
This is unlikely to be a house grounding issue, however make sure your ground and neutral are properly bonded at the service panel.

Are you sure you don't have a wall wart like Wifi supply or PC going on?

Good that you tried your TV cables! Most problems are coming from them.

I'd try to minimize your problems. Start with the amp, with nothing connected, then work your way towards your source. When you have the absolute minimum that causes hum, come back. :)

Best,

E
No wall warts and yes I disconnected the computer and cable line going into the modem as well. No change. 
Light dimmers can also cause this.

So what is the minimum system that causes your hum?

Best,

E
Do you have satellite tv? If so is there a phone line connected. I had trouble years ago and was able to acquire a isolater for the phone line and the buzz was gone. Another common contributor to this type of issue is the ground to the component. Have you tried lifting the ground to the Parasound? I have 5channel amp, that I have the ground lifted to eliminate a light buzz in the rear speakers.

I have cable tv and I turned off all lights when I was checking. Nothing seemed to work. I also disconnected the cable tv.  

HOWEVER - I diconnected everything but the amp (and speakers) no noise. 

I plugged in in the phono pre into the same wall outlet as the amp - no noise.

i connected the RCA connects to the amp from the phono preamp- NOISE!

so I guess there's a ground loop between these two pieces, what I don't get is why, both are going to the same electrical outlet. Only when the interconnects are connected do I get the sound.  If I connect a ground wire from chassis to chassis nothing happens. 

Any thoughts?
It's hard to tell if this is really a ground loop or a preamp noise problem.

Try, temporarily only, using a cheater plug on the preamp. See if this resolves your problem.

If it  does, that pretty much guarantees it's a ground loop issue. If NOT however.... it's a preamp noise issue.

E
@last_lemming
Did you try the polarity reverse switch? If not you should give that a shot!
i did try and the polarity reverse to no avail.

I also tried a cheater plug, but since I didn't have one designed for that purpose on hand I used an old extension cord for 2 prong components. It had a little bump out on the end to block the ground prong so a person couldn't "cheat". I cut this prong off and plugged the phono pre into it and promptly blew the fuse. I'm not sure why, maybe when I plugged it in I had the plug reversed?  Not sure.  
Also try wrapping your interconnect with aluminum foil.  It worked for my phono noise problem.  You can search and find my prior posts on this solution.
last_lemming said:

HOWEVER - I disconnected everything but the amp (and speakers) no noise.

I plugged in in the phono pre into the same wall outlet as the amp - no noise.

i connected the RCA connects to the amp from the phono preamp- NOISE!

Try not connecting the TT phono cables to the input RCA jacks on the phono preamp. Check for hum/buzz.
Still have the hum/buzz?

What TT are you using? Cartridge?

i connected the RCA connects to the amp from the phono preamp- NOISE!
That could very easily mean you have a defective RCA cable. Swap the RCA cable with a known good one that is shielded. 

What TT are you using? Cartridge?

I have a Dynavector 20x2L, and the cables are Cardas Clear Light.  They have never given me trouble before.  I don' t know if this matters but the noise is coming from both speakers, but I assume if one cable was bad then that noise would affect both, but I really don't know.


I will try swapping out cables tonight to see if that helps.

Blowing a fuse is not at all a good sign. I would now suggest you take the  pre to be serviced.

Best,

E
I replaced the fuse and it plays fine. 
last_lemming OP  265 posts                                              02-20-2017 10:46am

What TT are you using? Cartridge?

I have a Dynavector 20x2L, and the cables are Cardas Clear Light. They have never given me trouble before. I don’ t know if this matters but the noise is coming from both speakers, but I assume if one cable was bad then that noise would affect both, but I really don’t know.


I will try swapping out cables tonight to see if that helps.

//

Did you try what I suggested, disconnect the TT phono cables from the phono preamp? You said the hum/buzz was independent of the volume control setting, so just turn down the volume control and listen if the hum/buzz is still there with the TT disconnected from the phono preamp.

If the hum/buzz is gone then there something between the TT and the phono preamp going on. IF the hum/buzz is gone then I would say the problem, issue, is not between the preamp and power amp.

If the Hum/buzz is still there then the next thing I would ask is how close is the Parasound JC3+ Phono preamp to the power amp?

Try moving the preamp as far away as possible from the power amp. Especially the power transformer of the power amp. Try turning off and unplugging the power cords of any other equipment near the preamp. Only have the preamp, power amp and TT plugged into the AC power.
When did this problem arise?
I will try removing the cables tonite. However the TT has no power and is not directly plugged into anything (VPI prime TT). 

The problem arose when I moved my TT setup to another room and switched to single ended output from the phono pre instead of my XLR cable I used previously. The speakers in this new system are super sensitive (101 db) and these noise noticeable. 



Possible Problems:

Noise in the system, a hum or buzz:

o The answer is to ground the motor and system properly. A line filter that floats the grounds will not allow proper grounding of the phono system, the phono system must be grounded!!!!!! Phono is not like CD and if this is your first table or your return to vinyl after a decade or so you must remember that phono amplification can be 1000 times higher than CD or streaming so any noise that gets into the system will be amplified much, much more. Kill the noise with proper grounding and your system will sound much better.
http://media.wix.com/ugd/5e0564_3b9b738ded8246ab8e7fe7ce2ce0c3aa.pdf

//

Did you run a ground wire from the TT ground terminal/lug to the phono preamp ground terminal lug? The wire connects the TT arm as well as, I would imagine, the spindle bearing / aluminum platter to the signal ground of the phono preamp. (Signal ground, not to be confused with the earth ground.)

How about the TT AC synchronous motor. Is there any ground wire that connects from the motor to the TT?

Tonight when you try the tests I suggested make sure the TT AC motor is unplugged from the AC power.


I second Erik's suggestion of having a tech look at it. There is the possibility that a safety cap in the receptacle is leaking ac, especially the one from N to ground. If the fuse blew with that extension cord, it's possible you reversed polarity and ac went to ground through the bad cap, especially if there is an earth line choke between the safety caps. 

It's a long shot but it could explain why you're getting a groundloop even when plugged into the same outlet as the amplifier.
Am a bit confused about what has changed. Seems like hum came when you changed room...and the gear change was a switch to single ended rather than balanced cables from phono stage, and new speakers? Speakers and amp seem to check out ok, correct? But the phono cable introduces the noise? Can you go back to balanced cables to see if that matters? If not, can you adjust the gain level on the phono to see if that has any effect?
Ok, I did everything everybody said, and there is no change buzz is still there.

to answer a question from above I switched the room the phono pre was in and went from single ended to xlr because the tube amp doesn’t have xlr. I have had the same issue with an old Conrad Johnson amp, where it would buzz as well.

Could the tube amp be the culprit? Bad tube?

i also noted that the buzz/hum is older on different wall outlets. 
I second Erik's suggestion of having a tech look at it. There is the possibility that a safety cap in the receptacle is leaking ac, especially the one from N to ground. If the fuse blew with that extension cord, it's possible you reversed polarity and ac went to ground through the bad cap, especially if there is an earth line choke between the safety caps.

To be clear it made the noise prior to me trying to use the cheater plug that flipped the polarity. 
One more test.

With only the preamp connected to the power amp, TT not connected to the inputs of the preamp, unplug the preamp from the AC power.  Turn on power amp and check for the buzz/hum.




With only the preamp connected to the power amp, TT not connected to the inputs of the preamp, unplug the preamp from the AC power. Turn on power amp and check for the buzz/hum
Did this and no hum.  I'm not clear what that proves or disproves, if the preamp isn't plugged in then the ground isn't plugged in and no ground loop can occure. 
I just unplugged everything but the amp. I didn't notice before the same buzz/hum is there but bearly audible. This make me think that the noise is in the AC line. The phono preamps amplifies small signals so is it possible this bearly audible sounds becomes easily audible once it's boosted?
Just to add to the general dust cloud that the OP is removing hair over...

I had a persistent 60cps 'hmmm' that sent me on a search & destroy mission.  Went through the usual 'disconnect this/eliminate that' routine on my system to no avail.  Moved on to the ac circuit, unplugging or disconnecting everything, including the GFCI 's that were part of that line...

It persisted.  Visions of 'Reddy Kilowatt' giving me the middle finger salute.

Spouse said "Why don't you try a different circuit?"  Since I subscribe to 'the women are smarter' theory (as they've got us pretty much where they want us), I got out the extension cord...3 wire, of course.

*Poof*  Gone.  Beats me as to why.  Only operative reason may be a noisy breaker.  Since the existence of the new extension cord isn't a tragedy nor an issue I'm in no rush to buy a new breaker, BUT...

It could be that simple.  Easy enough to try, can't hurt to do so.

Good luck.  Spouse got thanks, big hug and kiss. ;)  She likes my hobby...she likes how it all sounds as well although the complexity of 'the mains' confounds her.  So the project at hand is to develop a simple 'work-around' for her to enjoy the solution as well. *S*  Marital bliss requires maintenance...;)
last_lemming OP 272 posts 02-20-2017 7:42pm
With only the preamp connected to the power amp, TT not connected to the inputs of the preamp, unplug the preamp from the AC power. Turn on power amp and check for the buzz/hum
Did this and no hum. I’m not clear what that proves or disproves, if the preamp isn’t plugged in then the ground isn’t plugged in and no ground loop can occure.

if the preamp isn’t plugged in then the ground isn’t plugged in and no ground loop can occur.
That is correct. Also if for some reason AC current is leaking from the neutral conductor to the chassis it is not passing through the signal ground wires of the ICs to the power amp chassis and out the safety equipment ground of the power cord to the equipment ground of the mains power grounding system causing the hum problem.

JMHO, it also proves the ICs from the preamp to the power amp are not causing the hum/buzz problem.
I would think it also says nothing is wrong with the power amp.

IF as gs5556 posted,
I second Erik’s suggestion of having a tech look at it. There is the possibility that a safety cap in the receptacle is leaking ac, especially the one from N to ground. If the fuse blew with that extension cord, it’s possible you reversed polarity and ac went to ground through the bad cap, especially if there is an earth line choke between the safety caps.
that could be your problem.

Especially if you did in fact reverse the plug polarity of the preamp when you plugged it into the 2 wire extension cord. Though I am not sure why you cut off the nub of the female cord cap of the extension cord when all you had to do was reverse the plug and the ground pin would not hit the nub. That would reverse the Plug AC polarity for sure though.

By reversing the plug the neutral conductor in the power cord would have become the hot conductor. IF the preamp uses AC line filter caps and the caps are leaking AC voltage through them, then the one on the neutral to ground would be hot to ground through the leaky bad cap.

But wait, you lifted the equipment ground on the 3 wire plug of the preamp. Yes, but the chassis of the preamp was still connected to the AC mains equipment ground by the signal ground wire of the 2 interconnects between the preamp and the amp. The Amp has a 3 wire power cord and plug, correct?

You could spend a few bucks and buy a polarized ground cheater and try lifting the ground pin on the AC plug again. With the polarized ground cheater you will not be able to reverse the plug polarity by accident again. With the ground lifted at the AC plug if it stops the hum then that would prove the hum is caused from an AC ground loop hum. LIFT THE EQUIPMENT GROUND FOR TEST ONLY.

Because you blew the fuse in the preamp the first time you tried to lift the ground on it, that tends to point the finger at the preamp being the problem, jmo.

EDIT
If gs5556 theory is correct lifting the ground at the plug will not stop the hum, imo.
The AC current will pass through the ICs to the power amp. 

By chance do you own a multimeter?
.
@last_lemming ... jea48 was very helpful to me in finding the cause of hum in my system.
I just unplugged everything but the amp. I didn't notice before the same buzz/hum is there but bearly audible. This make me think that the noise is in the AC line. The phono preamps amplifies small signals so is it possible this bearly audible sounds becomes easily audible once it's boosted?
An easy test would be to use a heavy-duty extension cord and run it to a receptacle on a different breaker, (as mentioned above). Then listen to amp only.
An easy test would be to use a heavy-duty extension cord and run it to a receptacle on a different breaker, (as mentioned above). Then listen to amp only
I have tried this but I didn't try ALL outlets. I can give it another try. 

By chance do you own a multimeter?

yes, what do you suggest?


last_lemming OP 273 posts                                             02-21-2017 7:01am
An easy test would be to use a heavy-duty extension cord and run it to a receptacle on a different breaker, (as mentioned above). Then listen to amp only
I have tried this but I didn’t try ALL outlets. I can give it another try.

If you can use a kitchen receptacle that is located above the counter top. The branch should be 20 amp.

Just curious what room is the audio system in now? Is the wall duplex receptacle, the audio system is plugged into, a 15 amp convenience outlet circuit? Roughly how old is the house/wiring?
The house is 15 years old. So new buy code standards. The room is a small bedroom. 
OP, I realize you already have a Furman Elite Power conditioner, but to the point of the thread (based on the topic title), there are plenty of electrical testing devices to check for proper grounding. 

Something simple like an Emotiva CMX-2 which can remove DC (not saying that is the cause of your hi/low buzz) also has line monitor LED indicators that detect "line correct", "open ground", "open neutral hot ground reversed", "open hot" and "hot neutral reversed". 
last_lemming,

I have another test for you if you have not already tried it.

With the preamp plugged into the AC outlet but powered off, not in standby if it has a standby feature, do you get hum/buzz through the amp/speakers?
I believe if the preamp has AC line filtering it is done near the IEC inlet connector ahead of the main power on/off switch. I am not 100% sure of that though.

Post back your results.

//

Voltage test measurements.

With the amp and preamp powered up check for AC voltage at the wall receptacle.
For the test if both receptacles of the duplex have plugs inserted in them slightly pull the preamp plug out just a little so you can touch the meter test lead probes to the far outside sides of the hot and neutral blades and the equipment ground pin of the plug. Caution, be careful you are dealing with lethal voltage. **Also I assume the wall plate is plastic or nylon. IT Can Not be metal.

Tests

1) Set meter to AC auto voltage. If the meter does not have an auto voltage setting set the meter to the closest scale above 130Vac. Setting will probably will be 150Vac.

2) Next with both the preamp and amp turned on, powered up, measure the voltage from the hot to the neutral at the wall receptacle. Write down the measurement. This measure will give you the loaded idle voltage of the audio equipment at the duplex receptacle. It should be around 120V. Above 124Vac is not considered good.

3) Next measure the Voltage from the Hot, (smaller straight blade slot hole of the two slots of the wall receptacle), to the safety equipment ground. Write down the voltage measurement. It should match the voltage reading as you got above. Though depending on all the combined loads connected to the 15 amp branch circuit it could be slightly higher due to VD, Voltage Drop, on the neutral wire of the branch circuit.
(This measurement also tells you the receptacle AC polarity is correct.)

4) Next measure from the neutral, the bigger of the two slot holes on the receptacle, to the equipment ground. For this reading hopefully your meter has an auto AC voltage setting. If not start with the scale used in the two previous tests and reset the meter to the lowest appropriate lower AC Voltage scale. Hopefully working down to an AC millivolt scale. Write down the voltage. The closer to a zero reading the better. Though depending on the VD on the branch circuit, the higher the neutral to equipment ground AC voltage measurement will be. Hopefully it is not above 1volt - 1.8 volts.

Post back your voltage measurements.

PS, if you want true loaded voltage measurements play some dynamic music at a moderate to above moderate to loud listening level. Then repeats the above test measurements.
.

Will do - just so I'm clear:

hot = smaller blade
neutral = larger blade
ground = small round hole below the two blade holes. 

I know I sound like a simpleton here, but I don't want to shock myself or damage the equipment. Also I'm assuming I will not damage the equipment as long as I follow the above procedure - for instance testing hot and neutral at the same time while equipment is on. 
last_lemming OP 275 posts 02-21-2017 3:22pm


Will do - just so I’m clear:

hot = smaller blade
neutral = larger blade
ground = small round hole below the two blade holes.

I know I sound like a simpleton here, but I don’t want to shock myself or damage the equipment. Also I’m assuming I will not damage the equipment as long as I follow the above procedure - for instance testing hot and neutral at the same time while equipment is on.

I made several edits in my last post. You might want to reread it again.

hot = smaller blade
neutral = larger blade
ground = small round hole below the two blade holes.

Hole slot sizes on the receptacle face itself. The hot and neutral blades on the 3 wire grounding plug are the same size.

I know I sound like a simpleton here, but I don’t want to shock myself or damage the equipment.

Don’t touch the metal probes with your fingers. Just make sure to touch the far outside sides of the plug blades. When touching the safety equipment ground pin touch it from the bottom side of the pin. You can also use the metal screw that holds the duplex cover plate on.

If it makes you feel safer wrap some electrical vinyl tape around most of the metal of the probes of the meter test lead probes leaving only the metal tips exposed.

Finally If you still do not feel safe measuring the AC voltages, Don’t do it! Safety first.

Also I’m assuming I will not damage the equipment as long as I follow the above procedure - for instance testing hot and neutral at the same time while equipment is on.
No, it will not damage any of your equipment. The multimeter is a high resistance meter. The branch circuit won’t even know you are checking it out.

Take your time. Again, if you do not feel safe don’t do it!
.
That clarifies everything.  I'm not too scared of it, i've done a little bit of electrical  investigation on cars and a little on homes but  I just like being very clear when I do stuff with it!
Ok here is the results with power of preamp and amp on:

hot + neutral = 120.5V+/-

hot + ground = 120.5V +/-

neutral + ground = .05V steady
GOOD NEWS!!!

So I found a proper cheater plug and tried putting it on the tube amp only - buzz completely gone whether the phono pre was on or off.  So it appears the amp was to blame and the phono preamp just amplified the problem.

So now, hopefully, when my new Decware integrated tube amp comes in it wont exhibit this buzz/hum, if it does at least I know its not the AC line.

I want to thank everyone who spent their time an energy helping me out!  I learned a bunch and tracked down my problem.
last_lemming OP 277 posts                                               02-21-2017 5:47pm

Ok here is the results with power of preamp and amp on:

hot + neutral = 120.5V+/-

hot + ground = 120.5V +/-

neutral + ground = .05V steady

The voltage measurements look great.
Neutral to ground AC voltage of 50 millivolts is ok.
With that said though IF there is an internal problem with the preamp and the neutral conductor is bleeding off somehow to the equipment ground conductor would a 50mv difference of potential, voltage, cause the hum you are hearing?

Per NEC code the safety equipment ground and service entrance neutral conductor is intentionally bonded, connected, together at the main electrical service panel and not at point there after.

If a difference of potential is present, (50mv), and a closed circuit exists, will current travel through the circuit? Yes, imo.

Someone like Al, ( almarg ), could answer that question. Hopefully maybe Al is following this thread and will chime in.

Curious what scale on the multimeter did you use when you checked the neutral to equipment ground voltage? The lower the scale the more accurate the reading.

//

How about the other test?

With the preamp plugged into the AC outlet but powered off, not in standby if it has a standby feature, do you get hum/buzz through the amp/speakers?
I believe if the preamp has AC line filtering it is done near the IEC inlet connector ahead of the main power on/off switch. I am not 100% sure of that though.

Check to see if you get the hum with the main power switch turned off on the preamp.
.
GOOD NEWS!!!

So I found a proper cheater plug and tried putting it on the tube amp only - buzz completely gone whether the phono pre was on or off. So it appears the amp was to blame and the phono preamp just amplified the problem.
The cheater plug on the amp did break the ground loop circuit, but that does not prove the amp is at fault. It could still be the preamp causing the problem.

So now, hopefully, when my new Decware integrated tube amp comes in it wont exhibit this buzz/hum, if it does at least I know its not the AC line.

Time will tell.

Good luck,
Jim
Jea48,

i did get the hum with the preamp turned completely off - though barely audible, it
was there, just not as loud. 
It's a good idea to have the amp and preamp on the same circuit to eliminate too many paths to ground. A cheater plug is usually safe as long as you have the interconnects plugged in though.
This is also the reason most of us use balanced cables now.