[Night_Thastus]

I run into a similar problem. I have a power-hungry GPU (3080) and CPU (9800X3D).

All my audio equipment was on the same UPS (and therefore outlet) as my gaming PC.

The result is that any time a particularly stressful game would be open, I'd get buzzing in the speakers. (Especially if the framerate was at 360) If you ask audiophiles online they will swear up and down that a cheater plug, balanced cables, or optical isolation will fix it - that will not fix it. It's not a ground problem. It's not coming from the connection from the PC to the DAC - it's a power issue.

It seemed almost inconceivable to them that the problem was EMI from the computer making it into the equipment.

I temporarily got a double-conversion UPS (converts AC to DC to AC again) and housed the audio equipment on that instead (separate from PC) Lo-and-behold the noise was completely gone.

However, those UPS are extremely expensive, and far worse they're very loud because the fans run constantly.

So, I went with a simpler alternative. Just get a power strip and plug all the audio equipment into that on a different outlet. That reduces it massively. You can also get some strips that are designed to reduce EMI, but I haven't felt the need as of yet.

[Gracana]

If you're a bit handy, you can assemble a line filter using a part like this https://enerdoor.com/products/fin27/ for a heck of a lot cheaper than you can buy a filtered power strip.

You may also be able to solve the problem with a simple common mode choke, either the clip-on type, or a toroid that you wrap the cable through a couple-few times. https://palomar-engineers.com/rfi-kits/acdc-power-line-choke...

[LM358]

A filter like that will have very little attenuation in the audio spectrum.

I agree however that indiscriminately throwing ferrites at problems can be a good solution!

[mrob]

Even if there's very little audio-frequency attenuation, it's possible for higher frequencies to produce audio-frequency intermodulation distortion, and filtering could reduce this. This is one reason "high definition" (ultrasound sampling rate) audio is a bad idea as a listening format.

[vlachen]

In 2013 I bought out 2 Radio Shacks worth of ferrite beads when I was hunting down signal noise in my senior design project (CNC mill rebuild and update.) All else fails, add more beads.

Also, I learned that you can make your own shielded flat cables with aluminum duct tape.

Who knew that they had a really good reason for using 48V signaling in the original machine controls from 1986?

[0_____0]

This reminds me of my favorite "Downfall" meme video.

[Youtube] "Hitler fails radiated emissions" - Orin Laney: https://www.youtube.com/watch?v=eeo8ZZTfwZQ

[actionfromafar]

Ferrites - almost never doing any harm, sometimes doing good. :-)

[Gracana]

Maybe you’re right. My experience is with radios, where it’s possible that high frequency noise is conducted into the RF section rather than into the audio amplifier. I know that in one case, both my transmitted signal and received audio output were absolute garbage (edit: because it was picking up noise from the vehicle ignition) until I added a choke to the power input wiring.

[brigade]

Well the OP’s electrical noise almost certainly is coming through the USB connection as their DAC has no external power supply. Extremely common.

Your problem of an AC power supply not sufficiently filtering out high-frequency noise from mains is exceptionally rare to the point that yes, I also don’t believe that was the correct diagnosis of your issue.

[monster_truck]

Pure sine wave UPSs are not that expensive anymore man. I think the biggest "desktop" pure sine wave cyberpower sells (1500VA/1000W, CP1500PFCLCD) is <$300 now. I have a couple of them, they are great.

[Night_Thastus]

It's not about pure sine wave - it's double conversion. Only double-conversion would actually isolate the equipment from EMI on the line. Without that pure sine wave won't do squat for EMI.

And one of those, even the cheapest ones, run for about ~$900. And they are LOUD.

[LoganDark]

Are they loud because they're double-conversion or are they loud because they're designed for server racks? When I search for double-conversion online I can practically only find rack-mount solutions.

[arde]

They're loud because silence is not a priority in their design and their fans run non-stop.

[Night_Thastus]

They're loud because unlike a regular UPS they need to run continually to convert the power back and forth. That generates a lot of waste heat, which fans must remove.

[icehawk]

I have several that are not rackmount (SU1000XLCD/SU1500XLCD), and they're all loud because they run fans constantly.

[saltcured]

I wonder if modern motor and power control tech could be adapted to make a desk-side motor-generator set that is efficient enough to rival an always-active, dual conversion AC-DC-AC UPS.

How efficient could a small AC->motor->generator->AC chain be with a modest flywheel mass to provide cycle-to-cycle stability?

Could it ever make sense to put one of these after a standby UPS so the output is always filtered by the motor-generator but the UPS only has to kick in for outages?

[mrob]

One advantage of a motor-generator set is that it's relatively easy to get high-voltage isolation using an insulating shaft. It might be possible to build something that could survive nearby lightning strikes to the incoming AC line. I don't think any standard UPS can do this.

[andyferris]

The portable lithium battery "powerstations" double as great double-conversion UPS in addition to their intended outdoors (camping, beach, etc) activities, and depending on capacity go for less than 900 USD. It's only noisy when fast charging or providing high currents.

Definitely had various computer equipment plugged in to ours and it was great (I didn't specically test for EMI).

[monster_truck]

In my testing combining this UPS with a cheap power conditioner, the noise floor is more than sufficient.

Sure, it isn't the -80db noise floor of a P-2400, but I'm not running a broadcast studio

[bob1029]

> If you ask audiophiles online they will swear up and down that a cheater plug, balanced cables, or optical isolation will fix it - that will not fix it.

Lifting the ground on my studio monitors absolutely fixed my noise problems. I run them off a MiniDSP 2x4HD, so other sources like EMI aren't really a factor.

The problem I have with a double conversion UPS is that it isn't an ideal sinusoidal source. It implies it is on the tin, but when you've got protected loads with PWM power delivery slamming around 1+ kilowatts, there's no way to guarantee a smooth waveform with a typical ~2500VA unit. Directly passing through to the grid could provide cleaner power under the most transient conditions.

[ck2]

isolation transformers are way cheaper than double conversion and should work as well?

well they used to be cheaper, not sure what is going with prices these day, I remember this being around $100 a decade ago

https://www.officedepot.com/a/products/146730/Tripp-Lite-500...

https://www.officedepot.com/a/products/493958/Tripp-Lite-100...

[crote]

It's not about isolation though - it's about line noise. An isolation transformer will let that pass straight through (minus the usual filtering due to any transformer being an inductor), whereas the AC->DC->AC conversion gets rid of all of it by effectively acting as a perfect low-pass filter.

[quickthrowman]

A 1.5kva isolation transformer is about $600, that fits with today’s pricing.

[bjoli]

Reminds me of my friend who has bought a shit load of 1.5v AA lithium batteries. The buck converters in those little bastards wreak havoc with every speaker around. His TV remote disconnects my Bluetooth headphones every time.

[madaxe_again]

Weird. Wonder if they chose 2.4ghz as their time division for the switching, because it’s a cheap and common frequency to source for.

[rcxdude]

They won't be switching at that frequency, but they're probably putting off harmonics up to very high frequencies due to very sharp switching.

[Yeask]

No need for UPS, a good external usb soundcard with power supply will solve that problem.

I have all connected to the the same power circuit and with a Elektron Digitakt as audio device and have zero noise.

With audio devices powered by USB there is a lot of noise.

[Night_Thastus]

Sigh, it's almost like I had this conversation before.

My audio equipment is not connected by USB. It's connected by optical (TOSLINK) to an external DAC. TOSLINK is not great, but it shows that it is not a USB noise problem.

[Yeask]

If you had that conversation before and you still having noise, maybe you are not doing the right thing... Sigh...

[Night_Thastus]

I got rid of the noise via the method I described in the original comment? Moving my audio equipment to separate power strip on a separate outlet. It didn't totally remove it, but made it quiet enough to deal with.

[butvacuum]

Don't mind them. I've had a similar thing happen, but with power line Ethernet. In your case however, I'd be at least a little concerned about the building wiring.

[Night_Thastus]

I ran into a similar problem! I briefly used CAT6, which is required to be shielded.

That shielding was carrying noise from my PC, through the network switch, to my raspberry pi that I used for music streaming. Absolutely nuts.

I swapped to unshielded ethernet cables and it went away.

As for building wiring, this issue has persisted in multiple buildings.

[blep-arsh]

I also have a splitter which lets you power an USB device from a separate power supply (i.e. D+/D- lines are connected to a host and +5V comes from a separate plug, ground is shared though). And optical TOSLINK is a nice option where available.

[nopurpose]

I got a lot of noise when plugging speakers to my display :(

[mainde]

When I upgraded my PC to the same CPU, I had the same problem of crackling/buzzing speakers on my USB DAC (externally powered, but from the same strip/outlet) when the system was under load.

I had a hunch it was power related because my PSU was nearly 10 years old and probably with just barely enough wattage. I bought a new one and all the buzzing went away.

IIRC when I was researching possible causes, beefy Ryzen CPUs were the most commonly mentioned in various forums and reddit threads.

[voldacar]

You could also chuck a bunch of ferrites on your PC power cord

[raxxorraxor]

It depends some setups generate noise when you move a cabled mouse with a high resolution. I never measured it, but I would assume it is because of the high frequency signals of the mouse generates if it is actively used.

In that case more isolated cables and connections would probably help.

[ThePowerOfFuet]

>the problem was EMI from the computer making it into the equipment

Do you have a PC case with a huge window? They (used to?) have grounded metal housings with only tiny openings for a reason.

[terribleperson]

So in your situation, noise from your PC was showing up in other equipment on the same circuit.

Did you try replacing the PSU?

[TacticalCoder]

> It seemed almost inconceivable to them that the problem was EMI from the computer making it into the equipment.

I very much doubt that because audiophiles worries about a lot about both RFI, EMI and unwanted vibrations (I had one where I could hear a very faint metallic noise and it took me weeks to find the cause: a loose screw in the system ceiling a times vibrating a bit, depending on the song / passage in the song / frequencies and slightly touching a metal stud: horrible to diagnose but eventually I found it). For a start.

If you go on audiophile gear shops, you'll find power supply that, supposedly, prevent EMI.

Are RFI issues much more common? Sure. I had one in a previous place where I lived where simply lifting the speakers cable of the wooden floor would remove unwanted sounds: some kind of radio or TV program my cables would pick up. Then suddenly I stopped making fun of people lifting their speakers cable of the ground (but I'll still make fun of those paying $100 per little piece to lift their cables then buying 50 of these).

That said your comment is very interesting. But it also shows that, suddenly, power strips (or others) that try to deal with EMI, balanced cables (between various piece of audio gear), lifting $20 speakers cables off the ground, etc. don't look as idiotic as many make sound (ah ah). EMI, RFI and unwanted vibrations are a thing and they do ruin the listening experience.

[NooneAtAll3]

> double-conversion UPS (converts AC to DC to AC again)

relevant xkcd https://xkcd.com/2651