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Cleaning USB for Bus Powered Audio Devices: Discuss

DWPress

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I'm the guy who made the split DIY USB cable referenced in the first post and along this thread. I tried the Dragonfly USB cleaner device, no improvement nor did a powered USB hub help. I had occasional problems after my cable solution as well.

Real solution: I bought a Macbook Pro to replace the 2013 iMac that was giving me the dirty USB power and all good now. (was not the only reason I upgraded computers)

That's a pretty drastic solution, I know, but it just seems that some implementations of voltage via USB is just plane bad or aging components on the MB may be the cause. Other DACs weren't affected using the same iMac but over the years I've had similar issues with DACs on other machines Mac & PC. It seems to me galvanic isolation is something that was known of 20 years ago and is so easy to implement in a build that all digital audio devices should include it by default. The D10 just seems to be more sensitive somehow.

Still happily using the D10 though
 

Krunok

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Take a USB cable and cut the +5v (red) cable. Run an external +5v power supply into the device-side of the UBS cable red wire that has just been cut.

I know how to do it, but why would I want to do that? It works perfectly well when powered from USB port.
 
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L5730

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I mentioned some time earlier that (a) the issue for me was found to be a ground loop (b) it was cured by breaking the ground connection from DAC to powered speakers. This maintains the USB common ground and thus means there is no risk of damage to either USB device or host.

If folks suffer from a flaky power supply, in the form of a shoddy implementation of USB power from their computer device, then using a Y-cable, whereby only the +5v (normally red) wire is connected to an external +5v power supply and no other power source, but the ground cable (normally black) is connected to both the PSU and the USB host device, should result in a trouble free experience.
USB host to device needs a common ground - it might work for a bit without a common ground connection (broken after initial handshake/enumeration/initialisation) but it runs the risk of causing damage as there is no longer a common reference voltage to which the data voltages are compared to. Additionally, as soon as sample rate is changed or PCM/DSD is switched the DAC will probably stop connecting properly.
Further, breaking the ground between host and device does cause some narrow band noise in the 8 kHz range.

For a real nice solution, the USB chip (XMOS etc.) should have a proper and direct connection to the USB host, and then the IIS data should be sent over galvanic isolation. It no longer becomes so much of a two-way communication, so fast one-way isolators can be used. The IIS signal would then enter the DAC chip and so on. DC-DC isolators can be sued for power, although it would then create additional losses, and may require more current, and thus an external DC PSU may be required. Jitter maybe an issue too.
Something like the Singxer F-1 board coupled with an ESS DAC chip instead of the HDMI and S/PDIF outputs would be a nice solution for a Galvanic isolated USB DAC. Price could be interesting though.
 

CerealKiller

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Same issue here. Topping D10 (also other dacs have been tried with same results) when conected to desktop PC becomes unusable for elevated USB noise from PC beeing passed by to DAC output.

Problemátic setup is, desktop pc , D10 via USB, JDSlabs atom for both headpones and ppwered speakers.

If aux conection in atom is fed by external source Say My phone or portable DAP, the noise completely disapears so it's not on neither the atom or the ppwered monitors. It comes from the PC and it's transfered to dac output.

If D10 is conected to laptop noise goes away.

Other DACs do sufer from the same issue. Audiogd R2R11. Unusable over USB, totally fine over optical Toslink.

Dx3pro. Unusable over USB, fine over optical.

Has anyone found a fix???

Update: usb to toslink works fine, D10 conected via usb to desktop PC and optical out of D10 feeding DX3pro then to atom as a preamp for monitors slash headphone amp. No audible noise whatsoever.
 
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Blumlein 88

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Same issue here. Topping D10 (also other dacs have been tried with same results) when conected to desktop PC becomes unusable for elevated USB noise from PC beeing passed by to DAC output.

Problemátic setup is, desktop pc , D10 via USB, JDSlabs atom for both headpones and ppwered speakers.

If aux conection in atom is fed by external source Say My phone or portable DAP, the noise completely disapears so it's not on neither the atom or the ppwered monitors. It comes from the PC and it's transfered to dac output.

If D10 is conected to laptop noise goes away.

Other DACs do sufer from the same issue. Audiogd R2R11. Unusable over USB, totally fine over optical Toslink.

Dx3pro. Unusable over USB, fine over optical.

Has anyone found a fix???
Have you tried a powered USB hub between PC and DAC? Sometimes those will buffer the noise from PC to the USB ports downstream of the hub.
 

CerealKiller

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Have you tried a powered USB hub between PC and DAC? Sometimes those will buffer the noise from PC to the USB ports downstream of the hub.
No i havent, but as some users in this treahd and others have mentioned that it does not solve the problem i skipped that.
 

Blumlein 88

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No i havent, but as some users in this treahd and others have mentioned that it does not solve the problem i skipped that.
Sometimes they do and sometimes they don't. Actually with the Schiit Modi (about the most sensitive to USB noise DAC there is) Amir found a hub which ran off the USB itself among the better ways to isolate from noise.
https://www.audiosciencereview.com/...regen-review-and-measurements.1829/post-46236

If you happen to have a powered or unpowered hub lying around might as well give it a try.
 

trl

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Same issue here. Topping D10 (also other dacs have been tried with same results) when conected to desktop PC becomes unusable for elevated USB noise from PC beeing passed by to DAC output.

Problemátic setup is, desktop pc , D10 via USB, JDSlabs atom for both headpones and ppwered speakers.

If aux conection in atom is fed by external source Say My phone or portable DAP, the noise completely disapears so it's not on neither the atom or the ppwered monitors. It comes from the PC and it's transfered to dac output.

If D10 is conected to laptop noise goes away.

Other DACs do sufer from the same issue. Audiogd R2R11. Unusable over USB, totally fine over optical Toslink.

Dx3pro. Unusable over USB, fine over optical.

Has anyone found a fix???
This is not USB noise, is most likely a noise coming from a ground loop. Try finding a dedicated thread for ground loops and get some more details, in there, about your entire setup from the mains outlet to the headphones/speakers
 

CerealKiller

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This is not USB noise, is most likely a noise coming from a ground loop. Try finding a dedicated thread for ground loops and get some more details, in there, about your entire setup from the mains outlet to the headphones/speakers
Oh i've fully read the thread about it, acgually ive started there. The thing is, PC and powered monitors are conected to the same outlet, a multi outlet extensión adapter actually. So no thing to do there, i do tried to separete them just for testing. Took an extensión and pluged the PC to a complete diferent outlet in a diferent room. Same results. Besides. Pluging headphones to the headphone amp yields the same result, pc noise, hdd activitie, mouse movement, gets pased via USB to D10 and from D10 out to jdlabs atom. If its a groud loop i do not know how to eliminate it. Cutting the USB cable ground cable seem to work acording to that post but im not to eager in bulding a custom cable that is sketchy because My awfull diy and soldering skills. Would much prefer the bloddy thing just working properly.

Just tried conecting de D10 as a conversor from usb to optical and fed that output to DX3pro. No audible noise, so data gets fine over from pc to d10. and noise is picked up by D10 and passed trough its outputs
 
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AnalogSteph

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Could it be that are are leaving the speakers plugged into the Atom while using headphones? If so, unplug them and see whether this doesn't fix the audio in headphone operation.

What model are your "powered" speakers? I very much suspect that they may be IEC Class I and introducing the ground loop this way, and that they also have balanced inputs. If so, you could try the following setup between Atom output and speakers:
2x RCA to 1/4" (6.35 mm) TS cable, unbalanced
1x Behringer HD400 "Hum Destroyer" (line isolator)
2x 1/4" (6.35 mm) TRS to XLR cable, balanced

Also use RCA cables with the lowest shield resistance you can find between D10 and Atom (which aren't necessarily the fanciest-looking ones, but they may be a bit on the stiff side). Many years ago, Reichelt sold some really solid composite video cables using proper RG-59 coax that weren't too expensive, and I used two 5 m (or even 10 m) pieces of that for a longer run between an FM tuner and my computer, marking them (all yellow RCAs of course) so I'd know which channel is which. Never had a problem with them, just the 1€ class RCA to 3.5 mm adapters I was using back then were utter crap.
 

BDWoody

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Took an extensión and pluged the PC to a complete diferent outlet in a diferent room. Same results

I made myself crazy tracking down a ground hum... Turned out to be a bad connection to a copper grounding rod outside the house...

Ground loop issues can be monstrously frustrating to deal with...
 

CerealKiller

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Could it be that are are leaving the speakers plugged into the Atom while using headphones? If so, unplug them and see whether this doesn't fix the audio in headphone operation.

What model are your "powered" speakers? I very much suspect that they may be IEC Class I and introducing the ground loop this way, and that they also have balanced inputs. If so, you could try the following setup between Atom output and speakers:
2x RCA to 1/4" (6.35 mm) TS cable, unbalanced
1x Behringer HD400 "Hum Destroyer" (line isolator)
2x 1/4" (6.35 mm) TRS to XLR cable, balanced

Also use RCA cables with the lowest shield resistance you can find between D10 and Atom (which aren't necessarily the fanciest-looking ones, but they may be a bit on the stiff side). Many years ago, Reichelt sold some really solid composite video cables using proper RG-59 coax that weren't too expensive, and I used two 5 m (or even 10 m) pieces of that for a longer run between an FM tuner and my computer, marking them (all yellow RCAs of course) so I'd know which channel is which. Never had a problem with them, just the 1€ class RCA to 3.5 mm adapters I was using back then were utter crap.
D10 outputs unbalanced RCA to a presonus T10 sub wich feeds balanced to JBL 305 gen 1 active speakers.

No, disconecting de RCA output of the atom amp and leaving it just as a headphone amp doesnt solve the problem, you can CLEARLY hear all the usb noise, hdd spining, mouse movement on headphones at moderated volume, 25% in low gain, can imagine what that goes when louder.

cables dont do a diference either
 

CerealKiller

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I made myself crazy tracking down a ground hum... Turned out to be a bad connection to a copper grounding rod outside the house...

Ground loop issues can be monstrously frustrating to deal with...
I certeantly suspect the building im living in doesnt have proper earth grounding, but im no electrician so hard to measure without a telurimeter wich I belive is the instrument for verifing earth conections.
 

mansr

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I certeantly suspect the building im living in doesnt have proper earth grounding, but im no electrician so hard to measure without a telurimeter wich I belive is the instrument for verifing earth conections.
For the purposes of this discussion, the quality of the actual earth connection doesn't matter as long as the wiring inside the house is proper.

To find the source of the problem, you need to identify some arrangement that makes it go away, even if unpractical. Disconnect from the PC anything with a separate power supply such as external hard drives, USB hubs, and displays. If the noise goes away, reconnect things one by one and see which are safe and which cause noise to appear. Once you have that information, we can try to figure out a solution.
 

CerealKiller

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For the purposes of this discussion, the quality of the actual earth connection doesn't matter as long as the wiring inside the house is proper.

To find the source of the problem, you need to identify some arrangement that makes it go away, even if unpractical. Disconnect from the PC anything with a separate power supply such as external hard drives, USB hubs, and displays. If the noise goes away, reconnect things one by one and see which are safe and which cause noise to appear. Once you have that information, we can try to figure out a solution.

As far i've tried the following omisions regarding pc components and periferials

PC, all hdds eccept the SSD containing OS, videocard, fans, all wireless adapters lan and kb/mice/gamepad, monitor, powered speakers (monitors) without any improvement regarding noise. Motherboard, cpu and ram has to be there to go so... I might be missing something else to disconect but i think that is it.

I'll make a video later today when i get home for ilustration.

Tanks!
 

mansr

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As far i've tried the following omisions regarding pc components and periferials

PC, all hdds eccept the SSD containing OS, videocard, fans, all wireless adapters lan and kb/mice/gamepad, monitor, powered speakers (monitors) without any improvement regarding noise. Motherboard, cpu and ram has to be there to go so... I might be missing something else to disconect but i think that is it.

I'll make a video later today when i get home for ilustration.

Tanks!
The noise you're hearing is (apparently) originating in the PC. For the noise to become audible through ground loops, two things have to happen: the noise must be present on one or more pins of the USB port, and (part of) the return current must be flowing through the RCA cables to the Atom amp.

What USB cable are you using? If it has a bad ground connection, you could easily get noise problems. It's worth trying a different one just to be sure. Also try different USB ports on the PC. Adding a powered USB hub between the PC and DAC might change something, so try that too if you have one around.
 

CerealKiller

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The noise you're hearing is (apparently) originating in the PC. For the noise to become audible through ground loops, two things have to happen: the noise must be present on one or more pins of the USB port, and (part of) the return current must be flowing through the RCA cables to the Atom amp.

What USB cable are you using? If it has a bad ground connection, you could easily get noise problems. It's worth trying a different one just to be sure. Also try different USB ports on the PC. Adding a powered USB hub between the PC and DAC might change something, so try that too if you have one around.

I found something! After reading your replies twice, realized that i've tried powering off the speakers but missed powering of or disconnecting the sub, well, it turns out, that powering of the sub shuts down the noise in jbl 305 (probably because the pass band crossover in sub out feeding monitors is active) and attenuates the noise on headphones connected to the atom a good bite, but not totally quiet.
Here comes the good part, disconnecting the line out from atom to the sub makes jbls quiet logically since no signal is being fed but also noise in headphones gets barley noticeable!

It is still there, if gain is set high and volume is cranked up i hear the chicks, clics, pops, hums, and so, but at a much more tolerable level, although decoupling completely and connecting dx3pro via toslink gets dead silent.

USB cables are those provided with D10 and DX3 pro, don't have any other type A to type B to try but they seem fine.
Different USB ports dont make a difference, at least not audible.

Well, so, i'm still in some kind of shadowed area, noise is generated partly in PC since just using D10/DX3 with atom via usb there is a little of it, but when atom line out is connected to powered speakers it all goes to hell. is it a ground loop im dealing with then?

Should i try to get ried of it or do the easy thing, sell D10 and buy E30 with toslink instead which is proven that wont have any issues, (dx3pro belongs in my living room set up and wife is missing the Bluetooth capabilities)

Thanks for all your help
 

Rigel

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Hi CerealKiller.

You can do a simple test.
Wrap one of the two connectors on the metal part of the USB connector of the cable, with thin cellophane tape, so that it does not make physical contact with the female. One turn would be enough.

If it is a noise related to the operation of the processor, can it also spreads through the power cables between phase and neutral, at least in my case, but I do not think that is the case.
 
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Wes

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I always clean USB plugs - DeOxIt works well
 
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