• WANTED: Happy members who like to discuss audio and other topics related to our interest. Desire to learn and share knowledge of science required as is 20 years of participation in forums (not all true). There are daily reviews of audio hardware and expert members to help answer your questions. Click here to have your audio equipment measured for free!

Ground Loop and pitched sound

OP
T

tsine

Member
Joined
Oct 27, 2020
Messages
38
Likes
5
Was just showing the sort of thing to get. I'm sure you can get it in Germany also.


EDIT - but that particular one is located in China anyway - so possibly also subject to taxes in Greece. (It is also available on the German EBAY - but still from China)
Very sad that I can't find any store locally . With taxes I am 99% sure it will cost me more that 30 euro to get it from ebay / china and it will stay at custom more than 1 month to be processed ..
 

Lambda

Major Contributor
Joined
Mar 22, 2020
Messages
1,549
Likes
1,271
It's very strange that a DAC measuring good is so prone to USB noise from a desktop computer ....
But this is one of the things DACs are not tested for at ASR...
You would need to inkjet Common mode currents /voltages in the USB input and RCA output to test for this kind of noise issue.

Some DACs have quasi floating (high common mode impedance) inputs or outputs (or both) and handel this verry well.
others just share the USB ground with the RCA ground direcktly.

My experience and the fact that this ifi (and toslink) thing exists sowed me this is a common problem in the real world.

Or finding an spdif board that i cant find any store around Greece
OR a Usb to SPDIF.
Go optical in the DAC!
this is why optical exists
 

tonycollinet

Major Contributor
Forum Donor
Joined
Sep 4, 2021
Messages
2,214
Likes
3,169
Location
UK/Cheshire
Its also why balanced connections exist. Unbalanced RCA effectivley came from a world when your sources and your amp were all close together, and the only long cables are the speaker cables which are not a problem since a passive speaker is never ground referenced. So problem of ground loops pretty much non existent.

The probelm here is relatively long RCA leads to the amplified speakers. Balanced connections have specificallly been created for long runs of line level signals with ground reference at both ends.
 
Last edited:

Weeb Labs

Senior Member
Forum Donor
Joined
Jun 24, 2020
Messages
449
Likes
1,058
Location
Ireland
OP
T

tsine

Member
Joined
Oct 27, 2020
Messages
38
Likes
5
But this is one of the things DACs are not tested for at ASR...
You would need to inkjet Common mode currents /voltages in the USB input and RCA output to test for this kind of noise issue.

Some DACs have quasi floating (high common mode impedance) inputs or outputs (or both) and handel this verry well.
others just share the USB ground with the RCA ground direcktly.

My experience and the fact that this ifi (and toslink) thing exists sowed me this is a common problem in the real world.


OR a Usb to SPDIF.
Go optical in the DAC!
this is why optical exists
In my case if you read the replies ifi defender didn't work either . When I installed ifi defender plus a very high pitched noise introduced in the speaker and very prominent .
With ifi defeneder speakers sounded like the fake Devices promising to keep mosquitos away .

Do you now any dac having quasi floating to resolve this issue ?
 
Last edited:
OP
T

tsine

Member
Joined
Oct 27, 2020
Messages
38
Likes
5
22 euros and with shipping 30 euros .....39 euros costs the asus xerox se locally if i go that route
I also saw that (just for educational purposes )
Does something like that degrades sound ? I read that can affect high frequencies and overall affect the signal

Is it similar to usb isolators or they use ferrite ?
71hf1dSsb9L._SL1500_.jpg
 
Last edited:

Lambda

Major Contributor
Joined
Mar 22, 2020
Messages
1,549
Likes
1,271
In my case if you read the replies ifi defender didn't work either . When I installed ifi defender plus a very high pitched noise introduced in the speaker and very prominent .
Sure the device is a rip off and did not work in most cases and it can cause other problems as you noticed.
Nevertheless it exists and it is marketed to solve this kind of ground loop issue.
Because its a common(mode :p) problem.


Do you now any dac having quasi floating to resolve this issue ?
not from the top of my head. but some of the bigger more esoteric (expensive) dacs have USB modules with isolation
https://www.audiophonics.fr/en/dac-...mi-i2s-input-24bit-384khz-tcxox2-p-12379.html
I would not suggest going this way.

I would uses a (powerd) USB hub as a first try. sometimes this is all it needs.
if not as i said
USB to Toslink, Toslink to DAC.
If there is still a problem upgrade to a dac with balanced output.
If there is still problem uses Isolation transformer.
SUB-2XX.jpg

If its still there call ghostbusters.


There is some intermediate steps you can do:

Or Ferrites.
https://www.audiosciencereview.com/...measurement-and-comparison.27937/#post-970936

All this will Reduce the problem but the best and most effective step is to go Optical.
Upgrading the DAC to Balance is also a good idea but expansive and not by itself guranteed to be 100% effective.

Ferrites beads are ceap and won’t hurt (good practice if you know you have noisy PC/USB) but the only reduce the noise.

Isolation transformer are often very effective (the good ones) but the good ones are also expansive and the Lower audio quality significantly.
this is why they are only a last option.

don’t uses crap like this on a good DAC.
Your better of with a 10€ Apple dongle behind an real usb isolator (for ~10€)

 

tonycollinet

Major Contributor
Forum Donor
Joined
Sep 4, 2021
Messages
2,214
Likes
3,169
Location
UK/Cheshire
22 euros and with shipping 30 euros .....39 euros costs the asus xerox se locally if i go that route
I also saw that (just for educational purposes )
Does something like that degrades sound ? I read that can affect high frequencies and overall affect the signal

Is it similar to usb isolators or they use ferrite ?
71hf1dSsb9L._SL1500_.jpg
That one is just a large ferrite and will only reduce the noise a bit - I know from personal experience. In my case as a rough estimate down to about 25% of the level wihtout it.
 
OP
T

tsine

Member
Joined
Oct 27, 2020
Messages
38
Likes
5
@
i don't think so.
normally this is how the cheap generic transformers for car "hifi" look
My usb cable (one I use for d50s ) is from a printer i had and has ferrites to both ends (I though at the time it would be better than the one included in the d50s box )
The cable looks like that but not gold plated . I guess this would have helped with noise but not.....
I saw the other thread and the cable with 7 ferrites on the usb cable ....

They say generally that ferrites(on analog signals not on usb cables ) also cut some of the upper high frequencies (affecting sound) maybe snake sience or something i don't know
aisens-a101-0011-printer-usb-cable-ferrita-double-screened-type-a-male-type-b-male-5m-black.jpg
 
Last edited:

tonycollinet

Major Contributor
Forum Donor
Joined
Sep 4, 2021
Messages
2,214
Likes
3,169
Location
UK/Cheshire
i don't think so.
normally this is how the cheap generic transformers for car "hifi" look
So it does (having just looked up cheap generic car transformers). In which case it'll be even worse - I'd very much doubt it contains sufficiently wideband transformers.
 

tonycollinet

Major Contributor
Forum Donor
Joined
Sep 4, 2021
Messages
2,214
Likes
3,169
Location
UK/Cheshire
@

My usb cable (one I use for d50s ) is from a printer i had and has ferrites to both ends (I though at the time it would be better than the one included in the d50s box )
The cable looks like that but not gold plated . I guess this would have helped with noise but not.....
I saw the other thread and the cable with 7 ferrites on the usb cable ....

They say generally that ferrites(on analog signals not on usb cables ) also cut some of the upper high frequencies (affecting sound) maybe snake sience or something i don't know
aisens-a101-0011-printer-usb-cable-ferrita-double-screened-type-a-male-type-b-male-5m-black.jpg
Those sort of ferrites are typically added to help with radio frequency emissions, rather than audio frequency. I've recently learned ( :p ) that they can provide limited attenuation of higher audio frequencies, but are unlikely to solve your problem here.
 
OP
T

tsine

Member
Joined
Oct 27, 2020
Messages
38
Likes
5
Those sort of ferrites are typically added to help with radio frequency emissions, rather than audio frequency. I've recently learned ( :p ) that they can provide limited attenuation of higher audio frequencies, but are unlikely to solve your problem here.
Monday will be my last day for decision . Also i found locally these types of ferrites for 1.20 euro 5mm 7mm or 13mm in diameter .


xlarge_20200423123042_antiparasitiko_filtro_thoryvou_ferritis_rfi_emi_emc_gia_kalodio_i5p2_3_5mm_mayro_oem.jpeg
 

tonycollinet

Major Contributor
Forum Donor
Joined
Sep 4, 2021
Messages
2,214
Likes
3,169
Location
UK/Cheshire
Monday will be my last day for decision . Also i found locally these types of ferrites for 1.20 euro 5mm 7mm or 13mm in diameter .


xlarge_20200423123042_antiparasitiko_filtro_thoryvou_ferritis_rfi_emi_emc_gia_kalodio_i5p2_3_5mm_mayro_oem.jpeg
They will have limited impact on your noise. See the link posted above by @Lambda for the ammout of attenuation you can get by putting multple (7 or so) ferrites onto a single cable.

My advice is to stop trying to find workarounds, bite the bullet and get an optical connection to your DAC. It is the cheapest and most effective solution for you.
 
Top Bottom