iPad Hum

Not sure if this is a common problem, or if there is a common solution.

CHAIN: iPad OR iPhone (Air and 6+) to Belkin iPhone Charge Plus Lightning Rockstar to Audeze Cipher Cable and LCDi3

PROBLEM: Slight 60hz (and probably 120hz harmonic) hum, more on left channel, when plugged into power. Have swapped USB power cords, sides of the Belkin, and power worts. No change. IT GOES AWAY WHEN I TOUCH METAL CASING OF iPhone OR iPAD.

I have 2 Cipher cables, and have not tried swapping them. Do we think its a defective Belkin unit? I got that because it’s Apple certified enough that Apple sells them, could have paid less for alternatives.

Noise disappears if I do not have unit charging. I think my temp fix is to try one of my external batteries as charge rather than AC. This is more practical than super-gluing my fingers to iPad case each night.

Thoughts appreciated?


That sounds like a ground loop.

Is the wall wort plugged into the same outlet as the rest of the gear (dac/amp)? If not ground loop is a suspect and can be tested by plugging wall wort into same outlet as other gear.


I’d say it’s the Belkin cable.

If it’s charging and trying to pass audio through, that’s probably the source of your hum.

Have you done a reset on the IPAD ? Home - sleep/wake button, be patient it could take 10-15 sec

@ValentineLuke, I just ordered a cheap alternative to the too-expensive Belkin dongle to try out. @NickZ yes, it does sound like a ground loop. But the wort is just a usb charger, I tried two. Never noticed the problem before. @cpp, no, because I tested this on BOTH the old iPad and the iPhone, the hum is cross devices!

Clearly connected to the AC. It starts and stops if I plug or unplug, and does not happen on battery. Nothing has changed on this setup for years, not even extension cord. And of course using Cipher/LCDi3.

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Wow this is interesting. Does it mater where in the home you tried it, different outlets ( non GFI maybe )

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A new connection to an ac outlet is a new place for ground loops to happen.

It may be due to a different outlet (I didn’t see if the wall wart is on same outlet as other gear) or it could be that the transformer or adapter is causing a change in ground potential.

You wind up with a new path from ac outlet to wall wart to lightning dongle to usb cable to dac to amp to another ac outlet. This is what creates the possibility for ground loop hum.

Did not try it on other outlets. I have an older home, sometimes have to hunt the newer 3 prong outlets, and only have GFI in the kitchen and one bath where we had more recent work done.

@NickZ, I connect this to an extension cord. The “wall wort” is just a USB charger on that cord, nothing else plugged in near there. The Belkin is described here:

About halfway down they dog and pony show the circuitry, talk about shielding. This device lists for way too much, but it’s available for only too much. I bought it new, probably an amazon vendor, not long ago. Also sold in Apple store. I just ordered a $10 device that is supposed to do the same thing - different design, uses cord split instead of fancy case. If that doesn’t fix the hum, I will try and track down my order and talk to Belkin.

I don’t see where the ground loop is happening. Unless it’s the DAC in the cipher cable to the charge to phone circuit in the Rockstar.


I’ve had good luck with this Ground Loop Noise Isolator. Never bothered to test how much (or if) it’s affecting the sound but I’m just happy the noise is gone and the price is right:

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Oh, wait, you are never going to 3.5 so that’s no help. Sorry.


Ugh, I’ve been rambling about the wrong scenario. When I looked up the Cipher dac I saw a unit that plugs into the wall.

Now I see there is only one ac connection for the charger.

This is a very strange thing because the lightning connection is digital data. The ground loops come about with analog interconnects.

My instinct is that the Belkin is the culprit but I don’t have an explanation for what is actually happening.


Any update on this headscratcher? I’m interested in what the fix ends up being.


Headscratcher is correct. The $10 cheap substitute to the Belkin doesn’t work, or at least not with the Cipher cable. Sound comes out of the iPad speakers.

HOWEVER, I notice this when I press the LCDi3 a bit deeper into my ear. With my finger. NOT when I press it a bit deeper with something non-conductive. Either left or right. Not when there is no external power. I did not notice this with the iSINE 20, but haven’t gone back to test. The LCDi3 is supposed to have a magnesium case, and I think the iSine 20 has plastic.

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At this point I advise buying some high-torque anti-static headphone shoes.

It’s the only way to be sure.


When I explained to my wife exactly what the problem is, she suggested:
“Just don’t push them in deeper with your finger”
so simple!

I’ve written to Audeze and to Belkin. Called Belkin’s 24/7 line, and their customer support person tried to be helpful, and is willing to replace the Rockstar. I’m not sure that it is actually defective, if it’s a design problem, if I need the high-torque shoes, or if it’s just me. I found years ago that I can’t wear Timex Illusion watches - my body’s aura blows them up - or more realistically, they just stop working within a couple of days.

It could be the Cipher cable. I have 2 of those and have not swapped. The Belkin dude first told me that I had put the charge into the wrong side, but I showed him on their web page that there is no wrong side. One of the “key features” interchangeability. Then he sent me two identical emails referring to their attachments with no attachments.

He did suggest I try different headphones. I pointed out that I really wanted to use these headphones, and quoted the LCDi3 list price. He got very quiet and said Oh, I see. I guess I could dig out my wife’s unused apple wired lightning earbuds that she got with her iPhone 11 and test those, but since they are plastic, I wouldn’t be able to create a ground loop. Or I could see if they shipped the dongle that gives a 3.5mm, and try the Moondrop Kanas Pro that have a metal case. But I don’t know if they would be connected at all the same electrically… dot dot dot.

Just checked the iphone box, no dongle for 3.5mm, just lightning plastic earbuds.

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Update: Belkin is sending me a new Rockstar, but they want to see a pic of my Rockstar with the cable cut. They shipped without the pic, so I think I’ll defer sending them one - at least until the new one arrives.

Audeze replied. They agree with my wife. “If you’re concerned about it, our advice is simply to avoid creating the ground loop by only touching the headphones when required, or unplugging them from the charging source while they’re in use.”

They go on to suggest " Another approach would be for you to check the ground paths in your system/environment, but unfortunately that’s beyond the scope of our support. You may find some helpful info in this search."

So I figure for $50, I might as well pick up an iFi Defender+ which is supposed to take care of ground loops. However I can only put it on ahead of the power connector to the Rockstar. Ideally I’d want it between the Rockstar and the Cipher cable. But that’s all lightning connector and I can’t find one that is lightning to lightning.

I tried placing my Jitterbug there, but no effect.

Audeze seems to think that this is not abnormal: “Since the headphones contain metal parts that may be connected to ground through the cable, touching those parts may induce a ground loop with some devices. This is normal and shouldn’t cause any problems. This is likely the result of introducing the charging circuit into your phone, introducing a loop to ground hum through the headphones that is being amplified by the internal amp in your Cipher cable. This can be caused by the Rockstar adapter, or may be the result of the grouding paths in your home’s internal wiring.”

I checked with Zappo’s and they don’t have EE width high-torque anti-static shoes in size 12.

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These don’t suck.

Anyway… Something smells fishy about the internals of something if the grounding changes when a human touches it. I don’t know if I’d be taking that as a final answer. Sure, check the cable and grounding stuff, due diligence and all that, but… yeah, fishy.


Hopefully the new Rockstar or the Defender+ will work.

Sounds like the vendors are just punting and blaming it on everyone else.

If it is a ground loop everything I’ve read says you need at least two connections to ac outlet to cause it.

Bummer about the shoes, I really thought that would fix it.

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No :game_die: :game_die:.
Today I got the iDefender+ and the replacement Belkin Lightning + Charge Rockstar. At first I thought that the placebo effect was reducing hum slightly, but not so. I’ve tried swapping all parts and using the USB-C side port of the iDefender+, all with essentially no change. With no iPad connected and the Audeze Cipher connected to a Belkin, I get hum, which can be stopped by touching the lightning connector that goes to the iPad.

I think that it’s possible a Defender-like device with a lightning pass through might work, because then I would be isolating ONLY the Cipher cable/LCDi3 side. As it is, the iDefender is plugged directly into the USB Power.

The iDefender+ is a curious device, have an LED of it’s own that has something to do with charging. Apparently iFi sees it being used with a DAC or amp such as the xDSD or xCAN.

Given the above, I think that the problem is that the charging gets amplified by the Cipher cable DAC. I guess that for longer listening times, the solution is the external battery in place of an AC connection.


Adding some thoughts:

Maybe it’s not really a ground loop, but a ripple. Although that doesn’t explain why I can make it go away by touching the connector or iPad.

HOWEVER, the fact that I do NOT get any noise when using an external battery instead of an AC USB charger makes me think.

Is there a clean, no-ripple, pure DC power supply available that I can simply plug into the AC and get battery-like power out? I have poked around the Internet :phone: and came across the Topping P50 Power Supply, which looks like it might work, but APOS customer support said Hmmmm.

Amazon has a somewhat cheaper - and more poorly specified linear power supply that is touted for Raspberry Pi and audiophile use.
I looked at the iFi iPurifier 2, and that does not look like it will fill the bill. Nor am I sure that the iPowerX from iFi would solve the problem, plus it does not have a USB out.
This also looks like a good possibility - in fact, they compare it to battery.

One ebay, this looks like a possible budget alternative:

Would appreciate thoughts and alternatives. Am I barking up the wrong tree?

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