Fix your Audio Ground Loop Buzzes and Noises

Started by admin, November 21, 2009, 06:43:53 AM

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admin

Quote from: ttk on May 18, 2019, 08:01:29 AM
Wait... but what does your electrical outlet look like?
Disclaimer: I live in France, and I don't remember having seen an outlet with only two poles!

A few place lack ground pin Japan and USA  only employ 2 on most AC Mains power cords 

GuitarBuilder

Quote from: ttk on May 18, 2019, 08:01:29 AM
Wait... but what does your electrical outlet look like?
Disclaimer: I live in France, and I don't remember having seen an outlet with only two poles!

Just because an outlet has a ground connection (pole) does not mean it was connected properly in the wall or electrical panel.  Having a home recording studio makes one keenly aware of poor grounding in homes, particularly older ones.  I even had a home where the previous owner put 3-prong outlets in when the wiring was only hot and neutral, no ground at all!  He had left all ground connections open!
"There's no-one left alive, it must be a draw"  Peter Gabriel 1973

admin



https://www.prosoundweb.com/topics/studio/eliminating_troublesom_hum_buzz_created_by_electric_guitars/

http://www.bartlettaudio.com/

Sidebar: Technical Discussion Of Body Grounding
by Jim Brown, Audio Systems Group

The human body is a conductor with relatively high resistivity, and it is a fairly large conductor. This means that when it makes contact with an electrical circuit it can act as an antenna, and it can also act as one "plate" of a capacitor.

The other "plate" of that capacitor might be a noise source like a power line, a noisy electric light, or computer wiring. The noise might be base band (that is, audio frequency), or it might be modulated RF, or it might be both.

The body will react differently to those noise sources depending on what they are—their frequency content, their internal impedance, their orientation with respect to the body, etc. And the body will interact with the circuit of the audio equipment and its wiring.

The various effects of the body in any given circuit will add algebraically—that is, they may be varying degrees of in phase, and they may be in or out of polarity, and they will be at various relative levels with respect to each other, so in any given field condition they will be different.

Some examples of the guitar problem. Let's say that the body touches the "hot" conductor of a guitar cord plugged into an amplifier. The body can act as both a capacitor, coupling both audio and RF into the equipment, and it can act as an antenna. What's the difference?

The word "antenna" implies reception or transmission of an electromagnetic field—that is, the simultaneous existence in space of an electric field and magnetic field at right angles to each other, and in which energy is traded back and forth between electic and magnetic fields.

An antenna has both current flow along it and a potential difference along it that either is caused by the field (reception) or generates the field (transmission).

So when the body is acting capacitively, it is NOT acting as an antenna, it is not "receiving noise" and coupling it to the equipment. It has become part of the equipment's wiring and is an element in the equivalent circuit. Now, the body may be acting as a capacitor to one noise source (or in one frequency range) and as an antenna to another, and may be doing so simultaneously!

Another way that the body can get into the act is by causing current flow on the shield of an unbalanced cable. That current can couple noise in at least two ways. First is the IR (or IZ) drop in the shield, which is added to the signal. Second is via a pin 1 problem.

When the orientation of the guitar is important, there are three mechanisms I can think of that can be at play. First and most obvious is the null that occurs when the circuit that is inductively coupled to a magnetic field is at right angles to that field.

Second is the movement of the body and the guitar so that it is physically closer to the noise source, and thus has a higher capacitance to the noise source.

Third is the directivity of the antenna that it is part of.

Suggested References
Radio Frequency Susceptibility of Capacitor Microphones (Brown and Josephson). AES Preprint #5720

Common Mode to Differential Mode Conversion in Shielded Twisted Pair Cables (Brown and Whitlock).  AES Preprint #5747

Testing for Radio-Frequency Common Impedance Coupling (the "Pin 1 Problem") in Microphones and Other Audio Equipment (Brown). AES Preprint #5897

A Novel Method of Testing for Susceptibility of Audio Equipment to Interference from Medium and High Freqeuency Radio Transmitters (Brown).  AES Preprint #5898

Noise Susceptibility in Analog and Digital Signal Processing Systems (Muncy). JAES June 1995


admin

#54
https://www.pedalsnake.com/blog/category/the-noise-manual/
Category: Guitar Noise Manual
Guitarists love high gain and distortion, but these often make for annoying, noisy rigs.  Past articles on the subject (supposedly by "experts") have treated all noise types as one thing, with an incomplete set of "try this and that", often proving futile and wasting time.

With this in mind, PedalSnake® offers the Guitar Noise Manual.  Each thorough, yet simply worded article targets one type of noise, and the ways to fix it.  Mobile friendly, to help you troubleshoot at the gig.

So...got noise?  Read on...and remember...


Dealing With BUZZ
BUZZ    The most common noise encountered by guitarists
SOUNDS LIKE    "brrrrrrrrrr", like a chain saw
https://www.pedalsnake.com/blog/2016/09/noise-series-dealing/#more-41




Dealing With HUM
HUM   A low tone caused by AC currents (60 Hz in the USA)
SOUNDS LIKE    "mmmmm", a low tone, a bit sharp of Bb
https://www.pedalsnake.com/blog/2016/09/the-noise-series-causes-and-solutions-to-hum/#more-11


Dealing With HISS
HISS    Most often encountered by high gain players
SOUNDS LIKE   "shhhhhhhhhh", a high-pitched white noise
https://www.pedalsnake.com/blog/2016/09/noise-series-dealing-hiss/#more-59


Dealing with POWER SUPPLY NOISE
POWER SUPPLY NOISE   Encountered by guitarists using power supplies to power their effects pedals
SOUNDS LIKE   lots of different things (sorry)  🙁
https://www.pedalsnake.com/blog/2016/09/dealing-power-supplies/#more-583



Dealing with DIGITAL NOISE (whine)
DIGITAL NOISE (whine)   Becoming more common as guitarists use more digital devices
SOUNDS LIKE   many high pitched tones at once, a subtle screech
https://www.pedalsnake.com/blog/2016/09/dealing-digital-whine/#more-599


Dealing with CABLE MICROPHONICS
CABLE MICROPHONICS   Every cable has it, to some degree
SOUNDS LIKE   noise thru amp when touching or handling the cable
https://www.pedalsnake.com/blog/2016/08/dealing-cable-microphonics/#more-601


Improving Signal-to-Noise Ratio
Reducing guitar noise can be tricky, but it is easy to boost the guitar signal to improve the signal-to-noise ratio (SNR), and some ways are better than others...
https://www.pedalsnake.com/blog/2016/08/improving-signal-noise/#more-653



Do I Need An Expensive Power Supply
Do you need an expensive power supply to have a quiet rig?  Strictly speaking, you do not.  But it depends on many things...mainly you.
https://www.pedalsnake.com/blog/2016/08/quieter-expensive-supply/#more-1160



admin

#56


https://www.allaboutcircuits.com/textbook/reference/chpt-2/wiring-color-codes/

https://en.cosel.co.jp/technical/qanda/a0006.html

There are two different name, L (Live)(Hot)  and N (Neutral) on the AC input terminal. Please refer to Fig. 1 for the wiring of the AC input. The terminal L must be connected to the unearthed conductive part of AC main supply and the terminal N must be connected to the earthed conductive part of AC main supply, to apply the safety agency approval. This purpose is protection by a blowout fuse from electric shock by earth fault.
Also, the terminal FG(Functional Ground)  needs to be connected to the earth to protect from electric shock and noise interference. Even if the terminal L and the terminal N is connected to another side or the terminal FG is not connected to the earth, then the power supply might not get broken and might not change its characteristic.
Even if terminal L and N are connected oppositely, power supply operates normally. However, please note that the conductive part would be kept under the earthing fault condition. Please note that conducted emission and ripple noise characteristics would be changed when FG is not connected to ground.
Most of AC-DC power supplies are classified as CLASS Ⅰ equipment in safety approval requirement, therefore FG terminal should be connected to the safety ground of the equipment.


admin

#58
https://www.diyaudio.com/forums/diyaudio-com-articles/163575-audio-component-grounding-interconnection.html

https://www.jensen-transformers.com/application-notes/

https://www.jensen-transformers.com/what-is-a-ground-loop/


I will share one strategy Ive used for years to tame  / Eliminate Ground Loop Noise

Today many employ an expensive "INDIVIDUAL OUTPUT ISOLATION  GUITAR FX POWER SUPPLY"

But 25 years ago these were not common, so instead
I relied on the Power Supply Ground to be the common Ground source of a Star Ground connection for all my Guitar effects 

I had a longer version of this type




I relied on the DC Power connection GROUND to be the ONLY common ground path between multiple Unbalanced Audio devices (Guitar FX)

Then on each shielded 1/4" TS cable used to connect between each Unbalanced Audio device (Guitar FX Pedal),
I would intentionally Cut the Ground Shield connection to the plug on only ONE side of the cable - which broke the analog signal ground connection between each device.
Easy to do on this type


But since most Guitar FX have the Analog signal Ground reference tied directly to the DC Power Input Ground  - everything worked very well, and much less noise

Caveat was the modified pedal board 1/4" TS cables with "Lifted Ground" would ONLY   be suitable as part of the permanent Pedal Board System   

quad4

Removing all wires between audio equipment and a computer solves all sorts of problems.

If the following wireless usb, virtualhere, works for you, it has a lot of benefits.
https://www.vguitarforums.com/smf/index.php?topic=27267.msg200387#msg200387


adamlee011

Quote from: adamlee011 on September 04, 2015, 06:26:29 AM
I thought when I got my vg99, hey this is awesome, xlrs to record the main outs and guitar out to an aux instead of a direct box! I'm going in through the behringer x32 which let's me route an  aux to a regular channel. Wow did I get noise! I only just found the lift switch on the sub outs yesterday so I'll have to try that.

I was wondering why I was alerted to this thread. Forgot I had commented here. Turned out, the usb was causing it. The lift switch might help if I need to use that again but since I rarely do, I just unplugged the USB and it stopped.

admin


pasha811

Quote from: admin on December 02, 2019, 03:06:58 PM
Understanding Guitar Grounding

https://www.fralinpickups.com/2018/11/12/understanding-guitar-grounding/



There's something I do not get and that might be the cause of some noise in my LTD-ST213.
I have a Fender Player Stratocaster from 2018 that is absolutely noiseless in every position.
Both Fender and LTD share the same wiring except that LTD shared the tone on the bridge/mid pickup.
Attached is the Fender service manual and jumpers are visible. The shield under the pickguard is conductive, there is conductive paint in the jack cavity for both my guitars. What I do not get is why jumpers? in the Telecaster example is made clear that if everything is connected by the plate (in this case the shield) jumpers are not needed. However my Fender Player is sooo quiet and my LTD is not except Bridge/Mid and Neck/Mid positions. I observe that the Fender player has an additional wire connecting the Volume pot to the shielded cavity that is missing from my LTD can it be the reason of noise?

Thanks
Pasha

Listen to my music at :  http://alonetone.com/pasha/

admin

#64
Quoteobserve that the Fender player has an additional wire connecting the Volume pot to the shielded cavity that is missing from my LTD can it be the reason of noise?

Worth a try!


admin

https://www.thegearpage.net/board/index.php?threads/are-dimmer-switches-ruining-your-good-time-aka-60-cycle-hum.2255921/
Heinz57 wrote>
Quoterecently moved and every circuit in the place seems to have a dimmer switch. Single coil guitars were basically unplayable.

I first bought a furman power conditioner (AC-215a), it didn't really help, (which by the way is 130 dollars on amazon vs 230 at sweetwater).

After that didn't work, I decided to try the Electro Harmonix Hum Debugger. It's a Miracle. So I bought a second one.

I thought maybe I could help someone fighting hum make the right choice first.

Not really a problem but the hum debugger requires AC juice, so make sure you have a plug available.

lespauled

As stated in that thread, the ISP Decimator II G-String is absolutely amazing.  The best noise suppressor I have ever used.  I hated the NS-2 because it affected your tone.  The ISP does not.  Just a fantastic piece of gear.  Worth every penny.

admin

#68
Ground Loops occur in any type electrical device

Same process to debug communication hum and noise in experimental aircraft applies when building large guitar systems








Elantric



Elantric