Understanding Grounding in Audio (Video)

[wwenze]

Is it white noise or 50Hz hum or some higher-pitched whine

 

[MASKINEN]

This is very interesting since I have a NAD T187 that introduced a low humming noise in all of my speakers. The T187 is upgraded with 4K and atmos/ Dirac modules. It’s connected to a Emotiva XPA-3 GEN 3 and a Parasound 5125.

The hum (50 hz since I live in Sweden) is very low and can only be heard from about 5-10 cm from the midrange. (Yes the hum is heard mostly from the midrange, not the bass drivers).

Can hum reduce sound quality even when it’s low and only heard from so close to the speakers?

I’ve tried everything is can think of, I have dc blocker on the mains and everything is powered from the same outlet. Tried other outlets, tried rca-xlx cables, tried IFi gnd etc. The building is only 5 years old.

I did make a post about this on here as well.
If you have any ideas, I would gladly accept them!

 

[phoenixsong]

This is very interesting since I have a NAD T187 that introduced a low humming noise in all of my speakers. The T187 is upgraded with 4K and atmos/ Dirac modules. It’s connected to a Emotiva XPA-3 GEN 3 and a Parasound 5125.

The hum (50 hz since I live in Sweden) is very low and can only be heard from about 5-10 cm from the midrange. (Yes the hum is heard mostly from the midrange, not the bass drivers).

Can hum reduce sound quality even when it’s low and only heard from so close to the speakers?

I’ve tried everything is can think of, I have dc blocker on the mains and everything is powered from the same outlet. Tried other outlets, tried rca-xlx cables, tried IFi gnd etc. The building is only 5 years old.

I did make a post about this on here as well.
If you have any ideas, I would gladly accept them!

It will reduce sound quality, but its effects are probably inaudible and thus negligible if they can only be heard within 10cm of the driver with all volumes set to listening levels without any music playing. Sounds like it's even softer than the likes of the JBL LSR speakers' hissing, probably only a few dB, and in a relatively insensitive region of the frequency spectrum too. Unless higher order harmonics get out of hand, I don't think it should be an issue. I'm rather inexperienced and new to audio science though, so take this with a grain of salt

 

[MASKINEN]

It will reduce sound quality, but its effects are probably inaudible and thus negligible if they can only be heard within 10cm of the driver with all volumes set to listening levels without any music playing. Sounds like it's even softer than the likes of the JBL LSR speakers' hissing, probably only a few dB, and in a relatively insensitive region of the frequency spectrum too. Unless higher order harmonics get out of hand, I don't think it should be an issue. I'm rather inexperienced and new to audio science though, so take this with a grain of salt

That’s for the input. My rig still sounds really good on high and low volume. We’ll see if I will ship the unit to a service center just to get it checked.. I’m thinking bad capacitors or some other component on the boards. Maybe PSU.

 

[Klint]

That is news to many people who have home theater AVRs with such connections and quite audible ground loops.

The answer was in the video and in Bill's presentation. Even though you have a double insulated device, there is capacitance between the chassis and the mains wiring that causes mains leakage and current to flow to the chassis of another device similarly situated but at different ground potential.

As I explained in the video, there is no such thing as a system with no ground loop. It exists by definition in any system using unbalanced connections. You get lucky that it is not audible vast amount of time. Not because it doesn't occur due to two-wire electrical connection.

Hi @amirm . I hope you can give me a comment here. I have 1 speaker connected to 1 mono power amp, silence. If i connect 1 rca to the amp i get a buzz. This is of course where i ended up with my root cause analyzis. Different rca´s tested different powercords tested. Amp is grounded.

 

[amirm]

Hi @amirm . I hope you can give me a comment here. I have 1 speaker connected to 1 mono power amp, silence. If i connect 1 rca to the amp i get a buzz. This is of course where i ended up with my root cause analyzis. Different rca´s tested different powercords tested. Amp is grounded.

What did you hook up to the RCA cable?

 

[Klint]

What did you hook up to the RCA cable?

Hi. Nothing. I get the sound when rca is connected to amp. Thank you.

 

[phoenixsong]

Hi. Nothing. I get the sound when rca is connected to amp. Thank you.

I wonder if this creates what they call the antenna effect?

 

[Klint]

Hi. Nothing. I get the sound when rca is connected to amp (D) Thank you.

Whent from TV blueray turntable ... disconnected everything in the system, of course lots of other equipment in other rooms not disconnected, and ended up here. This is the first connection when the sound appears. I have got two mono amplifiers and one 4 channel amplifier from same brand all of them get the noise Tested with 35y Sansui, no issues. Best regards Klint.

 

[Lambda]

@Klint so your only attaching a RCA cable that's not conectet to anything? And you get noise?

 

[Klint]

@Klint so your only attaching a RCA cable that's not conectet to anything? And you get noise?

Yes. Nothing else is attached.

 

[edechamps]

Hi. Nothing. I get the sound when rca is connected to amp. Thank you.

The cable is acting as an antenna. This is completely unsurprising with an unbalanced cable on a sensitive high-impedance input, especially if the cable topology is nothing short of perfect (or there are other problems like a leaky shield). The noise should go away if you plug the cable into a source that is powered on, because a source will apply a low impedance across the cable, effectively shorting it and thus preventing EMI-induced voltages from appearing (up to a point, of course - but it's usually good enough).

 

[Klint]

Pictures from my audio analyzer, iphone.

 

[Klint]

The cable is acting as an antenna. This is completely unsurprising with an unbalanced cable on a sensitive high-impedance input, especially if the cable topology is nothing short of perfect (or there are other problems like a leaky shield). The noise should go away if you plug the cable into a source that is powered on, because a source will apply a low impedance across the cable, effectively shorting it and thus preventing EMI-induced voltages from appearing (up to a point, of course - but it's usually good enough).

Does not do so.

 

[edechamps]

Does not do so.

What is your source? Does the noise persist when connected to a known low-impedance source that is battery-powered and not connected to anything else (say, a smartphone jack output)? Also, what is the make and length of the cable?

 

[Klint]

What is your source? Does the noise persist when connected to a known low-impedance source that is battery-powered and not connected to anything else (say, a smartphone jack output)? Also, what is the make and length of the cable?

Speaker-Amp-RCA, amp powered up. No source, sound. Any source, sound. 3 different cable brands tested. In 2 of the brands I have double cables. 5 tested, same result.

 

[Agent86]

Hi! New user here. I just viewed Amir's video and, in reading over the posts in this thread, it definitely made me rethink my grounding and power conditioning strategies I was planning to use to address the problem below.

I just picked up a Pass Labs Int-60 and swapped it in for my PrimaLuna integrated amp in the system below. The problem is that I'm having terrible static and popping noises that are issuing from the speakers, especially during the loud passages in the music.

I tried a lot of reconfiguration options with the power cords and moving components around, and my guess is that there's a fundamental grounding/incompatibility between the Pass Labs amp and my Lampizator DAC. I'm able to connect my amp directly to simple source devices (a cheapie Sony CD player or a BluSound Node streamer) without much problem, but when I incorporate the DAC into the chain, all hell breaks loose. Also, I did not have any previous problems with my PrimaLuna amp using the same source equipment.

I should mention that I'm a real idiot when it comes to electricity, though I do know that my wall receptacles are not grounded. I live in an older apartment in San Francisco where we have three-pronged outlets, but there's no ground wire in the wall. I had an electrician install a Furutech receptacle, and he informed that a lot the older buildings in San Francisco are just the same as mine.

If I'm understanding the prior discussions correctly, the best course of action is not to fiddle with signal grounding solutions but to look for a balanced DAC to work with the Lampizator. Is that right?


1) Amplifier: PrimaLuna Dialogue High Power with KT150. Now, I'm using the Pass Labs Int-60

2) Music server/renderer: Antipodes CX + EX;

3) DAC: Lampizator Golden Gate V1(R2R); single-ended, no volume control.

4) Speakers: Verity Amadis S

5) Power distributor:. Audio Sensibility Statement SE

 

[amirm]

The problem is that I'm having terrible static and popping noises that are issuing from the speakers, especially during the loud passages in the music.

This doesn't sound like any kind of grounding/power issue. It more sounds like a broken device in the chain.

 

[Agent86]

This doesn't sound like any kind of grounding/power issue. It more sounds like a broken device in the chain.

Thanks, Amir. I did have a fuse blow a couple days ago in the DAC, but I replaced it and it works fine with my PrimaLuna amp, but not my Pass Labs amp. And the Pass Labs amp will work with the RCA out from a basic CD player, but not from the Lampizator DAC, which causes a lot of noise.

Would there be any simple tests I could run to help pin this down?

 

[amirm]

Can you provide specific models of each? Like to check their specs to make sure you are not overdriving the amp.