Return of the Audio Interference: Part II - Balanced everything, quality DAC, HUM destroyer...And still noise!

[FiftyTifty]

Hi! I'm FiftyTifty, and you might remember me from complaining about power draw causing noise on my speakers.

Yeah it's back and I'm at my wits end with it. After getting the Behringer Hum Destroyer and using my Creative soundcard, it was tolerable but was slowly getting more and more on my nerves. Took my PC apart, cleaned everything, and this time made sure to add all the standoffs to the case and screw the motherboard to them. Since those standoffs are used to ground the motherboard's components.

Yeah well, turns out the sound card doesn't fit in unless I take off the shield, which gets super crazy interference just like the crap Realtek integrated one.

How bad is it? Absolutely awful. It's like hearing an unending dial-up tone even when the PC is idle. Here is a video with the audio cables plugged into the speakers:

And when the audio cables are out...It still happens. Not as loud and it's high pitched, but the exact same behaviour: When PC is idle, less noise. When PC is doing what I bought it for (gaming, Gaea, modding) it gets louder and more noisy. Unfortunately my phone couldn't pick up the high frequencies when I recorded it, so no point sharing the video.

What have I tested and spent lots of (I'm poor) money on? Well:

Optical -> Unbalanced DAC -> RCA -> RCA Speakers
Optical -> Unbalanced DAC -> RCA -> XLR Speakers
Optical -> Audio Interface (Roland Duo Capture Ex) -> 6.35mm TRS Speakers
Optical-> Balanced DAC -> XLR -> 6.35mm Speakers
Optical -> Balanced DAC -> XLR -> 6.35mm TRS Speakers
Optical -> Balanced DAC -> XLR -> 6.35mm TRS Hum Destroyer -> 6.35mm TRS Speakers

Did the above tests with USB connections instead of optical to the DAC or audio interface, same behaviour.

For DACs? I've tried the Schiit Modi 2 uber, some SMSL unbalanced thing, and a more expensive SMSL balanced DAC. All of them had this behaviour. USB -> DAC connection were even worse, with the noise being twice as loud, including on the Roland. Even when all the devices are on the same power strip (PC, DAC, audio interface, computer screen, speakers) and everything else powered off (yes, even the wifi router)? Nothing changed.

At this point, I'm going to get an engineer in to check out the wiring of the office and see if there's anything that can be done. In the meantime...I guess I can try different optical cables? What's a good brand that I can get in the UK? Lots of Chinese resellers on Amazon and Ebay, but actually can't find any brand recommendations off of Google.

 

[Blumlein 88]

With no thought at all I can tell you forget about other optical cables. Interference is not coming from that and no optical will change it.

My next thought if I follow you is it is either coming from the source prior to optical which seems unlikely it would get mixed into the digital stream or more likely it is happening at the speakers. If you are getting it with speakers unplugged at the input it seems it is the speakers. What speakers are you using? Still Yamaha HS 7?
Those are known to have such issues. Sensitive to RF. How close are they to your PC?

 

[RandomEar]

Hi. So the problem also occurs when all audio cables are disconnected and only the PC and speakers are powered on? If that is the case, I fail to see how any of the troubleshooting with different cables, DACs and so on would be useful. Options:

• Use a long extension cord to a different part of your building/flat and power either the PC or the speakers and the DAC using this cable, using an optical cable from PC to DAC
• Get a new high quality PSU for your PC and see if this solves it
• Switch to a different GPU and see if this solves it
• Get a 1000 W+ isolation transformer and power either the PC or the speakers and the DAC via the transformer, using an optical cable from PC to DAC

 

[Berwhale]

Does the noise go away if you unplug your screen from the mains power?

 

[kemmler3D]

Wrap the speakers in aluminum foil?

I think @RandomEar has good suggestions if that doesn't work.

 

[nerdstrike]

When I had horrible noises of this ilk (Civ 6 was a major trigger...) my situation was improved by re-organising the cabling (without necessarily being neat). The monitors are amplifying noise and it doesn't matter how decoupled your signal chain is when there's an antenna (cable) hanging off the amp that is picking up noise from the PC components. Try moving things around - it's free at least.

 

[Berwhale]

Wrap the speakers in aluminum foil?

I think @RandomEar has good suggestions if that doesn't work.

Foil works...

 

[Blumlein 88]

Had not seen that tin foil video. But I've done that or similar many times. Especially with phono preamps. HS 7s are known to be more prone to such issues. The tin foil can work even better if it were grounded in most cases.

 

[AnalogSteph]

So the HS series suffers from the Pin 1 Problem plus poor shielding? Quality construction right there...

I won't be surprised if the foil shielding is what'll finally do it for the OP. Any option of it being a ground loop has pretty much been eliminated at this point (the higher level when using the USB connection, that was a ground loop at play).

BTW, when using the HD400, both sides should be grounded. SMSL DACs have 3-pin mains connections but aren't necessarily, so may have been floating when using optical input, which possibly puts considerable common-mode voltage on the HD400. Try USB -> SMSL DAC -> HD400 -> speakers instead, or get some cables for 3.5 mm stereo to 2x 1/4" TS or twice RCA to 1/4" TS so you can use either the soundcard or one the unbalanced DAC.

On another note, try loosening and tightening your PC power supply screws several times in order to give the case a better ground connection.

 

[FiftyTifty]

Thanks for all the replies everyone! I wanted to respond sooner, but getting another GPU for my work & gaming was a nightmare. Bought an RTX Titan, had to get it repaired which was a massive ordeal for the tech repair guy but he got it sorted in the end. NVidia really did not want anyone repairing their GPUs.

So I switched to some Adam speakers I had spare, which made a bit of a difference. But the Vega 56 was somehow causing even the CPU to make electrical interference. Now after swapping to the RTX Titan, there's a tiny bit of hiss at load but it's less than what the AMD card did before it...well, did the noises in the video.

For the ground loop, I do wonder if the power sockets in this house have not got a proper ground thingy in them. When I have money (broke after buying new GPU, emergency plumber, insurance excess ) I want to see if an electrician can find any faults with the wiring. Then see about isolating all the different power cables, audio cables, and display cables.

I did try the screws on the motherboard and power supply, but it made no difference. And I think I damaged the ground gold plating on my soundcard ages ago...Wonder if I could get that fixed? The Creative X-Fi Fatal1ty Pro is such a good sound card, I bought it back in like 2010 and it just made things sound more better gooder than any Realtek thing even on my AM5 ASUS motherboard.

And no, the noise was still there even without a screen. It wasn't as bad, but it was always there. When it was connected with USB and I moved the mouse, you could still hear the weird chugging-hiss as the USB input was being processed.

I'll check out the foiling, but it's not very aesthetic lmao. Are there aftermarket solutions that make it look neat and tidy?