Tri-X Fury causing ground loop?

[SpecChum]

Gotta love how people ask for advice....then don't take it.

Sorry

I'm not doing it on purpose, I promise. I've been around for a long time, I'm a good guy, honest!

 

[Despoiler]

When you plugged your E11K into USB was it a USB port from the case or directly from the mobo?

 

[SpecChum]

When you plugged your E11K into USB was it a USB port from the case or directly from the mobo?

Tried both. Tried the USB sound blaster in both too.

 

[MrTeal]

Do you have a spare audio cable that you could try disconnecting the shield ground at the amp end?
If that solves your problem, it's probably loop related. If it doesn't, you'll need to look elsewhere.

 

[SpecChum]

Do you have a spare audio cable that you could try disconnecting the shield ground at the amp end?
If that solves your problem, it's probably loop related. If it doesn't, you'll need to look elsewhere.

Not audio, no, but I see where you're going with this.

I must have an old usb cable somewhere, I can try it on the E11K with the shield removed.

 

[Bryf50]

Could also get an optical spdif DAC. Total electrical isolation between the PC and the DAC.

 

[SpecChum]

Could also get an optical spdif DAC. Total electrical isolation between the PC and the DAC.

Yeah, it's a shame this x-fi HD needs a PC to run. Doesn't do anything at all when plugged into a wall charger

 

[SpecChum]

Not audio, no, but I see where you're going with this.

I must have an old usb cable somewhere, I can try it on the E11K with the shield removed.

I've just thought, this wouldn't work, would it? USB still has a ground connector pin. D'oh.

I don't have any spare RCA cables I can butcher

 

[Phynaz]

Borrow a power supply from a friend. I think what you are hearing is the high frequency EMI of a switching power supply.

 

[SpecChum]

Borrow a power supply from a friend. I think what you are hearing is the high frequency EMI of a switching power supply.

I do get your logic, but the question remains how come I can only hear the EMI when I use a grounded device? The E11k has no interference when it's running from battery, only whilst charging from a internal USB port.

Ninja Edit: And I can't hear it through headphones directly into the soundcard(s).

 

[RampantAndroid]

I do get your logic, but the question remains how come I can only hear the EMI when I use a grounded device? The E11k has no interference when it's running from battery, only whilst charging from a internal USB port.

Ninja Edit: And I can't hear it through headphones directly into the soundcard(s).

I'm with Phynaz on this. The noise is likely carried on ground, and the sound card might have some level of filtering (a ceramic cap?) - any sound card worth ANYTHING will have a bit of filtering on the supply. (Optoisolating the audio signal from the noisy PC supply is a great idea...either via an actual opto-isolator or via optical SPDIF) That's why the battery would have no noise - you might be seeing two different grounds, more or less. The cleaned up ground of the sound card via the audio cable and the USB ground that is probably connected directly to the switching power supply. As long as you are only connected to the audio cable and using the battery, your ground is isolated and filtered. The second you add USB to the mix, you get noise from it.

Experiment to test my hypothesis: You already know that the audio directly from your soundcard is fine. So instead: connect the Fiio to USB. Connect a splitter cable to your sound card's output. In one side of the splitter, plug in the Fiio. In the other side, plug in your headphones. With the Fiio turned on, listen to the headphones. You might just hear noise (aka, you have introduced a new path to ground that may be noisy...and may be the path of least resistance to ground.

tl;dr: USB power, from a PC that is running, is never going to be a clean source of power. Buy or build a high quality wall wort power supply. Makes me wonder why the Fiio does nothing to filter the USB connection though. Maybe they expect people to use a device that has a battery as a portable amp?

 

[SpecChum]

I'm with Phynaz on this. The noise is likely carried on ground, and the sound card might have some level of filtering (a ceramic cap?) - any sound card worth ANYTHING will have a bit of filtering on the supply. (Optoisolating the audio signal from the noisy PC supply is a great idea...either via an actual opto-isolator or via optical SPDIF) That's why the battery would have no noise - you might be seeing two different grounds, more or less. The cleaned up ground of the sound card via the audio cable and the USB ground that is probably connected directly to the switching power supply. As long as you are only connected to the audio cable and using the battery, your ground is isolated and filtered. The second you add USB to the mix, you get noise from it.

Experiment to test my hypothesis: You already know that the audio directly from your soundcard is fine. So instead: connect the Fiio to USB. Connect a splitter cable to your sound card's output. In one side of the splitter, plug in the Fiio. In the other side, plug in your headphones. With the Fiio turned on, listen to the headphones. You might just hear noise (aka, you have introduced a new path to ground that may be noisy...and may be the path of least resistance to ground.

tl;dr: USB power, from a PC that is running, is never going to be a clean source of power. Buy or build a high quality wall wort power supply. Makes me wonder why the Fiio does nothing to filter the USB connection though. Maybe they expect people to use a device that has a battery as a portable amp?

I'm fairly confident your hypothesis is correct as you've just described a ground loop, which is what I've been saying all along

I don't really want to use the E11K for the desktop, I'm just using it to test; I've got a Little Dot tube amp that I want to use for the desktop, but that's mains powered and I can't get rid of the noise which is what I was trying to do.

 

[RampantAndroid]

I'm fairly confident your hypothesis is correct as you've just described a ground loop, which is what I've been saying all along

I don't really want to use the E11K for the desktop, I'm just using it to test; I've got a Little Dot tube amp that I want to use for the desktop, but that's mains powered and I can't get rid of the noise which is what I was trying to do.

Yeah...I guess I disagree with people saying it's not a ground loop. I suppose you could check the resistance between the X-Fi's ground (and capacitance. Inductance gets harder) and the power supply ground. I suspect you'll find them a bit different.

Anyway...optoisolating transformers aren't a great idea in the end, I suspect - they won't really be linear. You want to lift the ground of the LD amp. I think I saw you need a solution for Europe, not the US - so search for a ground isolating adapter. That should take care of your problems.

Or build one - I believe what you'd want is to put between the amp ground and outlet ground is a ground loop breaker; It's something like a 10Ω 5W resistor in parallel with a .1uF capacitor (a quick look says this needs to be rated to 250VAC, class X or Y and have a flame retardant casing.)

Another take (different values than what I'm giving, but same idea)

https://xellers.wordpress.com/audio/13em7-tube-amplifier/

the entire amplifier circuit is connected to ground through a “ground loop breaker” consisting of a 47 ohm resistor in parallel with a 1uF capacitor.

 

[Jhatfie]

I had a similar issue recently. I replaced my Logitech Z5300's with Presonus Eris E5 monitors and Temblor T8 sub and had horrible, horrible noise when gaming and slight noise moving mouse around, opening windows, watching movies, etc. Headphones were fine, other speakers were fine. Tried a different power supply, tons of audio settings, front and rear ports, tested 3 different internal and external USB sound cards, different cables (TRS, RCA, etc), different power strips, different power outlets, tested outlets for grounding issues. Nothing worked. Spent hours trying to get it figured out.

In the end, my fix was to use the optical out to a FiiO D3 DAC and use the RCA out to my sub/speakers (Do not use the computer USB to power the D3, use the provided power adapter). Now everything is crystal clear. Still not sure what the cause is, but at least I found a solution that worked.

 

[SpecChum]

I had a similar issue recently. I replaced my Logitech Z5300's with Presonus Eris E5 monitors and Temblor T8 sub and had horrible, horrible noise when gaming and slight noise moving mouse around, opening windows, watching movies, etc. Headphones were fine, other speakers were fine. Tried a different power supply, tons of audio settings, front and rear ports, tested 3 different internal and external USB sound cards, different cables (TRS, RCA, etc), different power strips, different power outlets, tested outlets for grounding issues. Nothing worked. Spent hours trying to get it figured out.

In the end, my fix was to use the optical out to a FiiO D3 DAC and use the RCA out to my sub/speakers (Do not use the computer USB to power the D3, use the provided power adapter). Now everything is crystal clear. Still not sure what the cause is, but at least I found a solution that worked.

Thanks for this, and thank you everyone for your suggestions and for being patient with me; I do know I've been quite stubborn on this one.

I've come to a conclusion tho, I don't think I'm going to be able to do a system wide fix, I'm not competent or indeed confident enough with electronics.

I'm going to keep the sound blaster x-fi hd and buy a usb isolator which hopefully should fix the issue. My only concern is the isolator is rated for 200mA, so I hope the x-fi pulls less when using line out.

 

[SpecChum]

I'm extremely happy to report that the USB isolator completely fixed it!

I can now play musics AND GAMES through my little dot, woo hoo!

Thanks again for everyone, yes even those insisting it was EMI lol (jk, I thought it was at first, too)

 

[Phynaz]

Good news, glad you found a fix.

 

[birthdaymonkey]

I'm extremely happy to report that the USB isolator completely fixed it!

I can now play musics AND GAMES through my little dot, woo hoo!

Thanks again for everyone, yes even those insisting it was EMI lol (jk, I thought it was at first, too)

Great news! I'll definitely be bookmarking this thread because I've had noise issues like this come up from time to time on my systems and those of friends. The two working solutions: USB ground isolator or optical out from the PC.

I actually have a similar setup right now with a USB DAC/headphone amp and even a similar EVGA G2 PSU. Currently I just use headphones, but I've had it hooked up to powered Emotiva monitors via unbalanced RCA. Never had any issue with noise or hum. I wonder if the paint inside the case could indeed be a factor.