[SOLVED] Nin. Switch audio buzzes when docked - can i make a ground loop isolator?

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Controllerhead
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[SOLVED] Nin. Switch audio buzzes when docked - can i make a ground loop isolator?

Post by Controllerhead » Mon Oct 12, 2020 1:09 pm

I know there are tons of talented EE folks around here. Question:

My Nintendo Switch buzzes a ton through the headphone jack, but only when it is docked. Researching tells me this is a somewhat common problem and i need a "ground loop isolator" to balance the DC... or something. Is this something i can make? Might be fun. Looking for advice. Thanks!

EDIT: Solved! I bought one of these for 10 bucks. It works great! There is some minor degradation in the sound signal, perhaps, but the buzz is completely gone and i am very happy with the overall results; especially for the price point.
https://www.amazon.com/gp/product/B01L1 ... UTF8&psc=1
Last edited by Controllerhead on Mon Oct 26, 2020 10:50 am, edited 1 time in total.
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lidnariq
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Re: Nin. Switch audio buzzes when docked - can i make a ground loop isolator?

Post by lidnariq » Mon Oct 12, 2020 1:12 pm

In headphones, or are you plugging it into a sound system? It could only be a ground loop if it's the latter.

If it's heard in headphones, there's a problem with the power supply being not very "clean" and the audio hardware not rejecting power supply noise.

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Re: Nin. Switch audio buzzes when docked - can i make a ground loop isolator?

Post by Controllerhead » Mon Oct 12, 2020 1:24 pm

lidnariq wrote:
Mon Oct 12, 2020 1:12 pm
In headphones, or are you plugging it into a sound system?
Ok, headphones do not buzz. I tried a few stereo receivers and an capture card and they all buzz at varying degrees of somewhat awful. Volume control on the switch (i think its digital) has no effect on the level of buzz. It sounds like 60hz (i think).
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Re: Nin. Switch audio buzzes when docked - can i make a ground loop isolator?

Post by lidnariq » Mon Oct 12, 2020 1:53 pm

Ok, so it is a ground loop.

What's weird is that the Switch power supply is already not earthed, so I'm not entirely clear where the ground loop is coming from. Is the Switch power supply plugged into the same outlet as the amplifier is?

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Re: Nin. Switch audio buzzes when docked - can i make a ground loop isolator?

Post by Controllerhead » Mon Oct 12, 2020 2:58 pm

lidnariq wrote:
Mon Oct 12, 2020 1:53 pm
Is the Switch power supply plugged into the same outlet as the amplifier is?
Yes. I tried playing with power: Same outlets, different outlets, in an audio receiver, in capture device, and directly to independently powered pro grade studio monitor speakers each with their own power supplies. No luck.

From what i read, some Nintendo Switches have this issue.
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Re: Nin. Switch audio buzzes when docked - can i make a ground loop isolator?

Post by lidnariq » Mon Oct 12, 2020 3:15 pm

If isolation transformers were cheap enough, I'd suggest trying one. Unfortunately, even a 40W is a bit expensive for a lark.

Do you have a friend you can borrow their power supply from? It'd be interesting to try replacing yours with some other source of 15V and see if that changes anything.

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Re: Nin. Switch audio buzzes when docked - can i make a ground loop isolator?

Post by Controllerhead » Mon Oct 12, 2020 5:26 pm

lidnariq wrote:
Mon Oct 12, 2020 3:15 pm
Do you have a friend you can borrow their power supply from? It'd be interesting to try replacing yours with some other source of 15V and see if that changes anything.
I don't have any i can borrow from anyone at the moment... hmm... It outputs 5v @ 1.5A and 15v @ 2.6A, i don't think a USB-C phone charger would work with those dual voltages? The amps seem a little higher than a phone charger?

If this isn't an easy or simple thing to make, i'll probably just grab this for 10 bucks, it was recommended:
https://www.amazon.com/gp/product/B01L1 ... UTF8&psc=1
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Re: Nin. Switch audio buzzes when docked - can i make a ground loop isolator?

Post by lidnariq » Mon Oct 12, 2020 5:35 pm

My recollection is that the Switch's USB C voltage negotiation isn't quite standards-compliant, so a generic USB C charger may not work? But if you have other USB C power supplies you can give it a shot. USB C means that ought to be safe. <giggle snort> USB C's still such a SNAFU

But I do believe that it's not 5V and 15V simultaneously, and that marking means it can be either. Or possibly anywhere in-between.

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Re: Nin. Switch audio buzzes when docked - can i make a ground loop isolator?

Post by Controllerhead » Mon Oct 12, 2020 5:43 pm

lidnariq wrote:
Mon Oct 12, 2020 5:35 pm
But I do believe that it's not 5V and 15V simultaneously, and that marking means it can be either. Or possibly anywhere in-between.
Yeah, so, i'm not feeling brave enough to just start throwing power supplies at it... Nintendo is not known for being standards compliant, and ...I just don't have the knowledge to do that. I'll wait for a different Nintendo PS that i can borrow, and if that's it, maybe purchase a replacement in the future. I'll grab the ground loop isolator from Amazon for now and just try that in a few days.

Thanks for helping me diagnose it with the headphones though! Your knowledge is appreciated.
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Re: Nin. Switch audio buzzes when docked - can i make a ground loop isolator?

Post by calima » Tue Oct 13, 2020 12:43 am

There's an easy way to test ground hum problems. Use some wire to connect the device's ground to your house's, see if it affects the hum. Most exposed large metal surfaces are a device's ground.

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Re: Nin. Switch audio buzzes when docked - can i make a ground loop isolator?

Post by Garth » Tue Oct 13, 2020 2:57 pm

Noises get in when a signal is referenced against something that not really ground. People thing that connecting all the grounds everywhere to each other should fix it, and that ground is ground is ground; but that's not true.

The term "ground loop" is often misapplied, and the phenomenon is widely misunderstood. Countless times, I've given phone support to technicians installing our equipment in aircraft, where they misunderstand how noise is getting into the system, and they didn't follow our installation instruction manual, and they thought "ground is ground is ground," and thought they'd do better if they add a short connection from every part that's supposedly ground, to the airframe, or fail to isolate it as directed, and the result is that noise from the alternator, the gyros, strobes, etc. got into the audio equipment.

Here's a common scenario: An installer puts one of our units in a small airplane, and mounts the headset jacks with their bushings connected to the airframe at that point, assuming ground is ground is ground, instead of making the only ground connection back to the intercom the one in the cabling we supplied with the unit. (The intercom gets its only ground connection at the audio panel, and does not use a separate ground connection for power.) For the worst case, suppose the aircraft has the biggest engine option, requiring the battery to be in the tail of the aircraft to counterbalance it. The capacitor on the alternator to smooth its output voltage basically is the battery; but now all that noise current also runs through the airframe, and the airframe's impedance, although low, is not zero, and the current humps, multiplied by that impedance, develop a voltage. Now suddenly the headset microphones' signal is not referenced against what the intercom sees as ground, but rather against something else that has all this noise on it. Even if you were to short across the mic, there's a strong noise signal getting into the intercom's mic inputs.

Same with a music input. I had a customer who put a CD changer in the back of the plane, with a remote control, and brought the cables to the front and into our intercom (which has very nice performance for stereo music entertainment as well), but failed to observe this. This one was close enough to me that I could drive down and see his plane, a Beechcraft Bonanza, 6-place IIRC. Right away I saw what I suspected. Although the CD changer was mounted on the carpet on the back deck, the mounting hardware was metal, grounding it to the sheet metal underneath. I told him that would have to change. He took the screws out, and sure enough, the noise completely disappeared. So then he re-mounted it with insulating hardware. Happy customer.

It would be hard to say exactly what's causing your problem without seeing the setup, but I could stab a guess that the reason you don't get buzz in the earphones but you do with a stereo receiver is that the receiver is getting another ground connection through the third prong of the power cord. Contrary to what might seem intuitive, when I worked at TEAC in the early 1980's which made semi-professional tape recorders, I found that I had to remove the third prong from power cords on my test equipment to get rid of the noise. (I know the higher-ups, afraid of electrocutions and lawsuits, might have been unhappy, but I never told them. A third-prong adapter would have worked too, but I probably didn't have any handy and didn't want to say anything to anyone, so I just broke the third prong off the plugs and solved the noise problem, and the power plugs looked normal, with no 3-prong adapter giving away the fact.)
http://WilsonMinesCo.com/ lots of 6502 resources

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Re: Nin. Switch audio buzzes when docked - can i make a ground loop isolator?

Post by Controllerhead » Mon Oct 26, 2020 11:04 am

Garth wrote:
Tue Oct 13, 2020 2:57 pm
A very detailed response.
Interesting. Thank you for the detailed response!

Since this is a somewhat common issue that affects only some Nintendo Switches, it makes me think perhaps one of their factories somewhere did not ground something properly. The power supply is only 2 prong, hmm... I don't know... Anyway, the ground loop isolator did the trick to "fix" it, so, i am a happy camper. It sounds like you've lived a charmed life between working at TEAC, installing aircraft equipment, and 6502 programming. Your website is a wonderful resource too, i have referenced it many times, thank you =)
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Re: [SOLVED] Nin. Switch audio buzzes when docked - can i make a ground loop isolator?

Post by Garth » Mon Oct 26, 2020 1:48 pm

It
sounds like you've lived a charmed life between working at TEAC, installing aircraft equipment, and 6502 programming. Your website is a wonderful resource too, i have referenced it many times, thank you =)
You're welcome. There are additional major features I want to post, but it all takes so much time. My work at TEAC was in the early 1980's. I was in AM & FM broadcast radio transmitters before that, and in one brief FM transmitter installation job around 1990. That RF work, plus amateur radio, led me into working in applications engineering for a couple of years in the mid-1980's at a place that made VHF and UHF power transistors mostly for military radars and communications. I've been in the aircraft stuff since 1985, but in equipment design. I never did the actual installations, but I did give phone support to those who did. I did some consulting in circuit design over the last few years at a place that makes propulsion units for small satellites, at their request (ie, I was not looking for the work), but told them earlier this year I wasn't going to do any further work for them because all the red tape and bureaucracy drove me nuts. You can kind of understand the need for all the volumes of requirements you have to prove your design meets, and the certifications and so on, because although human life is not on the line, it's very expensive to launch a satellite into space, and if there's a failure, you can't just mail it back home for a repair. Nevertheless, my own temperament is not a good match for that kind of red tape. Fortunately our niche of the aircraft work is not like that. Clients usually evaluate our products and do their own exhaustive testing if required, whether it's for air medical transport, soldiers, or whatever.
http://WilsonMinesCo.com/ lots of 6502 resources

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