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[Update, no fix yet] Axe-Fx 3 Insane Hum From PC?

JoKeR III

Experienced
Total FALSEHOOD. If that was the case there would never be a ground lift on pro audio electronics. Check your AXE.
This refers to the SIGNAL ground for a balanced signal not an electrical EARTH ground. A balanced signal has a + (positive), - (negative) and shield ground. The Ground Lift interrupts the signal from the shield ground.

100% agree with FractalAudio, not safe or advisable in any way, shape or form to remove, modify or alter the ground pin on any 3-prong electrical cable or cord.
 

Tommy Tempest

Experienced
That's an audio ground lift, not a power ground lift. Two very, very different things. NEVER, EVER remove the ground from the power cable. This is incredibly dangerous.
If it was incredibly dangerous, it would be against the NEC to use cable ground lifts or conversion power cables. It's common in the computer industry. I think you misunderstood. I was not suggesting to the OP to cut the ground on the AXE FX.
Let me add Signal Ground lifts do not conform to Audio Engineering Society standard AES48. So basically any ground lift can be potentially dangerous. But cheater plugs and lift switches on pro audio gear still exist.
 
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Piing

Power User
Let me add Signal Ground lifts do not conform to Audio Engineering Society standard AES48. So basically any ground lift can be potentially dangerous. But cheater plugs and lift switches on pro audio gear still exist.

In the professional audio and video fields, the cheater plug has been identified as a serious safety problem. Its casual use as a method for avoiding ground loops in analog audio and video signals (to eliminate hums and buzzes) is dangerous.[5] Bill Whitlock, president of Jensen Transformers, writes, "never, ever use devices such as 3 to 2-prong AC plug adapters, a.k.a. 'ground lifters', to solve a noise problem!"[5] Whitlock relates how an electrical fault in one device that is connected to its electricity source through an ungrounded cheater plug will result in dangerous, high current flowing through audio or video cables. Whitlock notes that in 1997, consumer audio and video equipment electrocuted nine people.[5]

The cheater plug is also recognized as a safety hazard in laboratory settings. For example, in August 2005, Tarun Mal, an associate professor at Cleveland State University, was electrocuted when he plugged a defective fluorescent lamp into a time switch using a cheater plug.[9] Subsequently, the state of Ohio issued seven citations to the university for unsafe electrical conditions.[9] The Scientist notes that four of the University's seven environmental safety experts agreed that use of the cheater plug "is not uncommon in US university labs".[9] Jim Kaufman, CEO of the Laboratory Safety Institute, says, "When you inspect labs, it's not unusual to find anywhere from one to seven that way."[9]

https://en.wikipedia.org/wiki/Cheater_plug

 

FractalAudio

Administrator
Fractal Audio Systems
Moderator
Let me add Signal Ground lifts do not conform to Audio Engineering Society standard AES48. So basically any ground lift can be potentially dangerous. But cheater plugs and lift switches on pro audio gear still exist.
No they don't but they are included because many products do not properly terminate the ground on their XLR inputs. Ideally the cable shield should be grounded at one end only (preferably at the output) and connected to signal ground via a capacitor at the other end. However many, and in fact most, products simply ground the cable shield which can cause a ground loop. The ground lift switch breaks the ground loop.

A ground loop occurs when current flows in the shield. This happens if two devices have different ground potentials which can occur when plugged into different outlets with different ground potentials or if if the ground path creates a large loop area. In a perfect world ground potentials would be the same everywhere but this is rarely the case. A large loop area creates an inductor and any magnetic field intersecting that loop normal to the plane of the loop will induce current in the loop. Using short cables and keeping power cords bundled together helps reduce the loop area.

Lifting the ground on a cable shield does NOT present a safety hazard as this is not the means of grounding the chassis. The chassis is grounded via the power cord. It is important for the chassis to be grounded in the case of a fault condition. The insulation between the AC power and the chassis can fail. If the chassis is grounded this will cause the breaker to trip. If the chassis is not grounded the chassis can then become energized exposing the user to lethal voltages.

Lifting the ground on a computer is extremely bad practice. PC power supplies are notoriously inexpensive (i.e. cheap Chinese junk) and AC faults are not unusual. Lifting the ground can expose the user to deadly voltages. Furthermore lifting the ground on your PC will typically make any interference problems worse as the chassis is then floating. For proper shielding the chassis needs to be grounded and grounded well (and not have any stupid windows).

NEVER, EVER use a cheater plug as a ground lift. If you need to break a ground loop the first place to do it is at the audio cables. If it is an unbalanced cable you can do this simply by disconnecting the shield ground at one end, preferably the receiving end. If it's a balanced cable you can use the ground lift switch if so equipped. If there is no ground lift switch you can disconnect the shield ground inside the connector. You can buy XLR cables with the ground only connected at one end. Fractal Audio products use our proprietary "Humbuster" outputs which cancel shield ground noise.

As an absolute last resort you can use a ground isolator like an Ebtech Hum-X. This lifts the chassis ground by using a pair of diodes in anti-parallel. In the event of a AC fault the diodes will conduct tripping the breaker (hopefully before the diodes fail). Under normal operating conditions the chassis will be floating which will break the ground loop.

Oh, and I should add that the intended use of a cheater plug is to adapt a two-prong outlet to a three-prong cord by utilizing the faceplate mounting screw as a safety ground. Prior to the introduction of Romex, plastic junction boxes and three-prong outlets residential wiring used metallic conduit and metallic outlet boxes. Therefore the outlet box was grounded. A cheater plug then allows adapting a three-prong power cord to the old style outlet boxes by connecting the ground wire to the outlet box via the faceplate mounting screw. A cheater plug is NOT intended to be used as a ground lift.
 
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DLC86

Power User
Ideally the cable shield should be grounded at one end only (preferably at the output) and connected to signal ground via a capacitor at the other end. However many, and in fact most, products simply ground the cable shield which can cause a ground loop. The ground lift switch breaks the ground loop.
So wouldn't a switch that engages a capacitor be better than completely breaking the connection to ground?
 

PincoTech

Inspired
You need one solid isolated 20 amp circuit, that's properly grounded, with no dimmers, as a starting point!! If you find a properly wired/grounded outlet to test, and its shared with appliances, or light dimmers etc., make sure they're all turned off. If you have hum after that, it'll be easy to find, but i doubt you'll have any. also separate all power wires from audio cables. having a nest of tangled up wires will cause humming, and static.
 

wagnar

New Member
I got one same type of computer, windowed type; all colors rgb...
plugged my monitor headphones to axe, powered down the pc and there was no noise, all were clear. The previous "rhytmic emi" sound was gone.
I will try making a faraday cage with some cardboard and foil but my macbook air seems to be the answer for me.

-edit-
--unshielded pc tower generates too much audible clicks and growls when guitar is near the tower (2 to 10 centimeters)
--even in 2 meter radius, the tower still generates an audible and distinguishable noise in mid-high gain settings.
--the pc had shut down and noise is gone. Literally nothing is catched by pickups. Verified that all noise is generated from RGB Rainbow colored, glass cased PC.
--I found an aluminum sheet metal and connected it to pc tower's metal case (unpainted part - and of course first verified that there are no voltage leaks). when I am as far as 2 meters to tower with this setting the noise is still there but significantly lower, maybe the lowest.
(All power strips are connected to a power supply unit and test guitar is not shielded. Later tried with the active pickups and they eliminate this emi interference a lot) This kind of inconvenience is enough for me to change the computers. I will be using mac for this sole purpose and keep the tower for gaming, editing, designing ..etc. I do recommend anyone to do the same.

Result: The LEDs and RGB colors are all wonderful, but noiseless recording and listening is priceless.
 
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PincoTech

Inspired
I got one same type of computer, windowed type; all colors rgb...
plugged my monitor headphones to axe, powered down the pc and there was no noise, all were clear. The previous "rhytmic emi" sound was gone.
I will try making a faraday cage with some cardboard and foil but my macbook air seems to be the answer for me.
Glad to hear you narrowed it all down. If your MacBook is fast enough, and your happy with the DAW software etc, just run with it. A mac won't crash, corrupt files, or run unnecessary resources in the background like a PC.

Hope you enjoy the rest of your thanksgiving making music!
 

UberGuitarDude

New Member
I got one same type of computer, windowed type; all colors rgb...
plugged my monitor headphones to axe, powered down the pc and there was no noise, all were clear. The previous "rhytmic emi" sound was gone.
I will try making a faraday cage with some cardboard and foil but my macbook air seems to be the answer for me.

-edit-
--unshielded pc tower generates too much audible clicks and growls when guitar is near the tower (2 to 10 centimeters)
--even in 2 meter radius, the tower still generates an audible and distinguishable noise in mid-high gain settings.
--the pc had shut down and noise is gone. Literally nothing is catched by pickups. Verified that all noise is generated from RGB Rainbow colored, glass cased PC.
--I found an aluminum sheet metal and connected it to pc tower's metal case (unpainted part - and of course first verified that there are no voltage leaks). when I am as far as 2 meters to tower with this setting the noise is still there but significantly lower, maybe the lowest.
(All power strips are connected to a power supply unit and test guitar is not shielded. Later tried with the active pickups and they eliminate this emi interference a lot) This kind of inconvenience is enough for me to change the computers. I will be using mac for this sole purpose and keep the tower for gaming, editing, designing ..etc. I do recommend anyone to do the same.

Result: The LEDs and RGB colors are all wonderful, but noiseless recording and listening is priceless.
Can you post a pic of your makeshift cage? I literally tried wrapping most of my PC in foil to achieve this but it made NO difference. I'm hoping I just made some failed attempt at it and didn't do it correctly, because as of right now I still haven't found a solution to this issue. It's definitely associated with the PC and proximity to it.

EDIT: Also I don't quite have the luxury of running on a mac as I livestream music sometimes on my stream, so my current setup requires me to be streaming from my main rig still and running into the line-in on my PC.
 

UberGuitarDude

New Member
Not sure if I mentioned it previously on this thread, but I did notice that I have no ground in any of my outlets - hah nice and safe. Would that be adding to the noise? I can't imagine that's the biggest source of sound issues, but it definitely can't be helping anything.
 

pauly

Fractal Fanatic
no ground?!?
omg get that fixed before someone dies mate!
pauly

Not sure if I mentioned it previously on this thread, but I did notice that I have no ground in any of my outlets - hah nice and safe. Would that be adding to the noise? I can't imagine that's the biggest source of sound issues, but it definitely can't be helping anything.
 

UberGuitarDude

New Member
no ground?!?
omg get that fixed before someone dies mate!
pauly
Yeah uhhhh, apparently that’s what I’ve been using for 4+ years and just realized it. Have everything on a decent surge protector, but I know that’s not the same thing. Also I’m in a rental and my landlord is not the best. No chance of getting this fixed.
 

pauly

Fractal Fanatic
good luck - I hope you get a chance to get out of there before it gets you.
thank god youre using a fractal and not some spitty old bassman.
hope you consider this a serious as it is.
thanks
pauly

Yeah uhhhh, apparently that’s what I’ve been using for 4+ years and just realized it. Have everything on a decent surge protector, but I know that’s not the same thing. Also I’m in a rental and my landlord is not the best. No chance of getting this fixed.
 

wagnar

New Member
Can you post a pic of your makeshift cage? I literally tried wrapping most of my PC in foil to achieve this but it made NO difference. I'm hoping I just made some failed attempt at it and didn't do it correctly, because as of right now I still haven't found a solution to this issue. It's definitely associated with the PC and proximity to it.

EDIT: Also I don't quite have the luxury of running on a mac as I livestream music sometimes on my stream, so my current setup requires me to be streaming from my main rig still and running into the line-in on my PC.
2019-12-02.jpeg
2019-12-02 (2).jpeg

When I am on a high gain preset (for ex: High Gain Recto's no noise gate), the noise starts to take place after string vibration decays. As I go away from the tower; the noise decreases "exponentially" I think. I assume using longer cables, putting the tower down and far away could solve the problem. I have seen one of my friends made a faraday shield with the tower's cardboard, he says it works for him.

Regarding your post about your grounding issue I would like to add my experience 4 years before. AfterI purchased my mini recto, I heard an incredible hum from amp. I took the amp and cabinet and went home, I knew my houses ground was properly done before. There were no hum and no noise. Called the engineers to original place and they measured that earthing was near 0.

Can you make a video or capture the sound of that noise ? maybe you already solved the emf problem but suffering from ground ?

I took some sound samples for clarification. Taken with audacity through macbook air. Air norton Pickups at full volume. Axe preset is "LT MK8 - MKIV Chunk"


Check this playlist, the first noise was my problem, changing guitar's pickup position helps, getting away from pc helps, what truly amazes me is of all those emf around; axe is still silent as an owl flapping at night. ( I hear nothing even in highest gain and output settings when volume of guitar is at 0)
 
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