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...
I agree however that indiscriminately throwing ferrites at problems can be a good solution!
I just know that if I handed over something with such shoddy soldering to a customer, I'd lose my job or at the very least lose soldering privileges. But I am working with things that cost slightly more than 99$ that you can't find on store shelves :)
I don't agree with that sentiment. Their designs are subpar and the quality of the soldering is (maybe was) unacceptable:
https://www.audiosciencereview.com/forum/index.php?threads/h...
https://www.audiosciencereview.com/forum/index.php?threads/b...
The above review specifically goes into the problem from OP.
There's also their amplifier with a rather non-standard architecture that tries to solve a non-problem (injecting feedback in a NFB loop - I might remember wrong, if so, forgive me) which leads to it measuring double digit (!) THD if you feed it a sine wave. I'm not an experienced engineer but it is IMO a non-starter to have an amplifier try to decide what is and isn't a musical signal as part of its protection circuitry, short of detecting DC offsets or shorts (pun not intended). I'm not in the market for a 1800$ amplifier that goes bzzzt if you feed it music it disagrees with [1]
https://www.stereophile.com/content/schiit-audio-ragnarok-in...
>Noise from using USB power delivery for audio devices is common.. that’s why you can (and should) use the dedicated power input to you DAC/amp
I don't disagree with your point. However, a company designing products like these should be able to design a filter for this usecase unless you're trying to use your DAC as a a measuring device, or there is something seriously wrong with your motherboard. I honestly haven't heard of any other brand product with this problem unless it's ~20 years old and in need of repair. It doesn't cost much in the BOM, however it does cost in engineering hours/competence and QA and this is something that should have been caught by the latter.
[1] https://www.youtube.com/watch?v=NzMbY4sZvIw
Edit: I just want to add that I don't want to hate on Schiit. Honestly I'd like new audio companies to succeed and I applaud them for rejecting MQA back in the day and for not going all-in on the audiofool bullshit one sees too much of. But seeing such poor engineering and QA leaves a sour taste in my (electronics engineering) mouth. Maybe they have improved lately, I wouldn't know. I'm not really in their market anyways.
It was mesmerizing to look at all the beautiful equipment and meet all the cool people there. I've forgotten his name, but I spent at least one hour with an ex-Tektronix employee who started his career with tubes and ended it with writing FPGA code who told me many wonderous stories from his career. Highly recommended if you're at all into electronics!
I was thinking of playing a pink noise on the speaker and recording it with a cheap microphone or displaying it with the Spectroid app, but the microphone probably has it's own frequency response.
Is there an App for that ? With each phone model microphone factory calibrated ?
Is there a way to use known fact about physics like harmonics should have a specific shape (timbres) that's should help equalize frequency with respect to each other ? Or from various microphone positions, calibrate it so that any cheap microphone can do the trick ?
Some municipalities also have a separate property tax which iirc is usually an order of magnitude lower than the wealth tax.
https://en.wikipedia.org/wiki/European_Citizens%27_Initiativ...
Not to make everything political, but I wonder how the US tariffs will affect electronics-adjacent hobbies. Anecdotally, the flashlight community on Reddit has been panicking a little about this.