Chris @FireP403nix
Interesting Stuff 
Is this how it works ? Ferrite bead - Wikipedia
Whatās your opinion on stuff like this ? 10 PCS Ferrite Bead Choke Coil Ring Core Rfi Emi Noise Filter Snap On Cable Clip | eBay
Kind Regards, Kevin
1 Like
Yes, very much interested to learn more about this!
What kind of ground loop noise isolator did you use/do you recommend?
https://www.sescom.com/products/view/category/categoryslug/il-19-hum-eliminator-series
Iāve used these in live sound situations for as long as I can remember. They have saved my butt in problem venues with bad power or when a mysterious gremlin arises and there is no time to troubleshoot.
1 Like
Ernst,
I have absolutely no experience in this domain. I understand that black box that attenuates or removes high frequency noise will be good for your application. However I always try to understand the physical principal to a black box device, after all in the world there is rarely magic, just physical phenomenon and nicely designed products to help improve things 
So I was wondering if a āGroup Loop Noise Isolatorā is basically a ferrite bead or is it more complicated than that
Certainly practical experience from @FireP403nix & @Jzad is very interesting to have
Iām not sure how much ferrite beads will help in your situation. You stated more of a ground loop hum then a high frequency noise. Ferrite beads reduce more of the high frequency radio waves that cause interference. Also Iām looking at this picture
And looking at what you call preliminary finding and conclusions. Iām gona go out on a limb and I donāt want to offend but cāmon really. Why would anybody do that? That just doesnāt make sense. I donāt know of any designer who would use this type of placement. This is seriously kind of a duh moment. Of course there will be noise and hum in that proximity and relationship to the power supply and the audio circuitry. There isnāt anything you can do fix that if that is how close you are mounting your devices. You could place a shield between them but even then Iām confused why anyone would do that. Also power and signal should not run parallel to each other. If power and signal wires need to be in close proximity or cross paths they should cross each other in a perpendicular configuration. Just good practice.
I used something similar to this:
1 Like
I have had some testing with ground loop isolators/filters in the audio signal line. But with no effect.
@Jzad - You are right about placement in proximity as a potential problem source. I have now enlarged the distance between the Up2Stream Mini and the PSU. The PSU is now in the same area as the PSU of the active speaker I am using in this project. This already makes a difference. Also I have shielded cables now both for the audio (between the Up2Stream audio-out and the amplifiers audio-in. But also for the DC 5v coming from the PSU to the Up2Stream Mini. This also makes a difference.
After that I tested other PSUās (230AC > 5vDC) and found that the iPhone USB PSU is less ānoisyā than the others I tested.
Still I believe I have to eliminate the 230AC>5vDC PSU for the Up2Stream Mini. To avoid potential ground loop, and noise from a switching PSU.
I am currently looking at a more audio-grade, low-noise/ripple DC>DC converter. So taking a DC voltage point from the amplifier/power side of the active speaker itself. The module I am considering for that is: https://bit.ly/3jqizNr
I would appreciate any comments/advice on this approach, and whether this module is advisable or if to choose for a different one.
Let me know!
My experience with these is that they ruin the sound quality, They are basically either a capacitor or a transformer inside those little boxes - often both! Both inherently are filters in their own right so will not perfectly pass the signal and will either roll off the top or bottom end to one extent or the other. Great units for live performances and problem solving but this is not a HiFi solution.
As per my previous post, adding a little attenuation on the output of the Arylic board before it gets to the amplifier will sort the majority of noise issues as without attenuation any noise in the system gets amplified 100%. Attenuating the signal from the board will also attenuate the noise - turn up the music on the Arylic app and the noise will stay low. Signal to noise ratio is what itās all about.
Use a linear power supply. Any phone PSU or DC to DC converter or switch mode power supply all use complex electronics that introduce noise as they chop up the voltage into high frequencies and radiate noise all over the place. No HiFi equipment I have seen ever uses switch mode PSUs for this very reason.
1 Like
Thanks @JJJJBBF
I know the linear power supply is what it should be. But these are simply to big in size for my project.
Therefor I am looking at a low noise/ripple DC>DC converter, and test if this works better.
I know this is an old topic, but just in caseā¦ I experienced excessive noise from my up2stream pro in 2 occasions:
1- when it was connected to a dual output usb adapter, and the adapter was shared with an echo dot. It now has its own good old rectifier-caps-capacitors analog linear power supply. (JJBBF is correct)
2- when the wifi antenna was within an inch from another analog component in my system. The noise stopped when I moved the antenna, it is now at ~5 inches from any circuit and all is well.
Hi @Jeannotvh , welcome to the forum!
Indeed this is an old topic, and in the meantime I have learned a lot about this. First of all I have to point out that I used the terms ānoiseā and āhumā, but in fact I was experiencing something else called ārippleā.
āHumā is normally caused by a ground issue.
āNoiseā is often caused by bad wiring picking up disturbances. Especially in the signal path. I only use shielded audio cabling for my projects, and I always check if there any āopenā connections. Or if I work with older amplifiers, I always check if the soldering hasnāt cracked and needs reflowing.
So in my case I had trouble with āRippleā. And in the end I found out that the Mini (I use them a lot) and especially the DAC on the Mini, is sensitive to causing this ripple.
By adding the external and optional DAC from Acrylic, I solved this issue. This one has a better quality DAC and shuts off the DAC on the Mini.
Hope this helps.
1 Like
Thank you @KolfMAKER , in my case the noise was more like a periodic tic-tic-tic, resembling closely to a scratch on a vinyl record. Cheers.
It appears that your digital circuitry is picking up electro-magnetic interference off of the other components when itās too close, as @KolfMAKER mentioned adding a separate DAC usually solves this type of issue.
If you do decide to add a DAC, make sure that the I2S interconnects are as short as possible.
Another possible fix is to add earthed metal shielding (like a Faraday cage) between the components, this might help too
Thanks @Steve1 for joining the conversation. Always nice to meet you again!
@Jeannotvh
I suspect that what you describe, might be the same as I experienced. Can you sent me a direct message via the forum with your email address? Then I will send you an audio file with the recording of the ripple sound I had.
(Unfortunately, I cannot upload a file directly to this topic or to you)