PC noise interference. strange behavior.

[Koop]

My Crack is dead silent except for the fact it picks up noise from my computer.. Everytime I open a page on browser/application, scroll the mouse wheel, or no activity at all, there's an electronic noise happening constantly. I could describe it as a highly compressed mid frequency that's oscillating and gets more intense if there's more activity on my computer... So it's definitely on the motherboard.

my signal path is as follows : PC USB out (Cardas USB cable) -> wyred 4 sound recovery USB re-clocker (which has its own power supply) -> Arcam rDAC USB (own power supply) -> audio quest golden gate RCA's-> Crack. I've checked all my USB ports, disconnected all USB devices except the Arcam - the noise still happens. Moved the Crack 10ft away from the PC and plugged into a different power outlet. Still noisy.

Now the odd thing is, I've discovered that this noise seems to be picking up via the RCA cables. Before the audioquest cables I was using two single Van Den Huul cables and wrapped them around each other like a DNA strand and that made the noise at least 50% quieter.
The audioquest cables seem to pickup way more noise.. and I do like the sound of them more. So I'm stuck on what to do from here.

[Deke609]

I'm far from an expert on such things, but I've spent a good amount of time fussing with the setup of my Intel NUC Roon server and DAC connection.

Couple of questions:

(1) Are you by any chance using your home electrical wiring as wired internet connections via ethernet adapters that plug into a wall socket? If so, try removing them to see if the noise disappears. I tried those adapters once but quickly removed them b/c of all the crap they put on the AC lines.

(2) Have you tried moving the amp AND THE DAC away from the computer?

(3) Does the USB cable from the computer to your DAC have one of those RFI/Ferrite modules on it? They look like a small barrel around the cable.  If not, you might try one.

(4) How close is the modem/router to your setup?

If it is the RCA interconnects picking up RFI, you could try putting a copper braid sleeve around each interconnect and attaching the braid only to the shell of the rca connector that attaches to the DAC -- or even try wrapping them in tin foil with foil attached only to the DAC end connectors to test whether a more permanent solution along these lines would help.

cheers,

Derek

[Doc B.]

The Audioquest cable you mention seems to have a non-traditional multiple layer metal/carbon filled plastic shielding arrangement. The manufacturer shows cartoon drawings to demonstrate "dramatically less modulation of the signal". I can't say I find that a very convincing approach to proving their effectiveness. I'd be inclined to try a different cable and see if the problem improves.

[Paul Birkeland]

I would recommend trying the optical input on your Arcam DAC.

[Deluk]

Try it without the reclocker "thing" in the system. As it has it's own power supply it may be adding this noise when under any load. You might even like the sound without it anyway. Not trying to be provocative there. 

[Koop]

I'm far from an expert on such things, but I've spent a good amount of time fussing with the setup of my Intel NUC Roon server and DAC connection.

Couple of questions:

(1) Are you by any chance using your home electrical wiring as wired internet connections via ethernet adapters that plug into a wall socket? If so, try removing them to see if the noise disappears. I tried those adapters once but quickly removed them b/c of all the crap they put on the AC lines.

(2) Have you tried moving the amp AND THE DAC away from the computer?

(3) Does the USB cable from the computer to your DAC have one of those RFI/Ferrite modules on it? They look like a small barrel around the cable.  If not, you might try one.

(4) How close is the modem/router to your setup?

If it is the RCA interconnects picking up RFI, you could try putting a copper braid sleeve around each interconnect and attaching the braid only to the shell of the rca connector that attaches to the DAC -- or even try wrapping them in tin foil with foil attached only to the DAC end connectors to test whether a more permanent solution along these lines would help.

cheers,

Derek

thanks for the feedback!

1) I'm running an ethernet cable straight from my PC into the router which is in the other room (20ft away, to also answer question 3)

2) yes, DAC and amp away from the computer and the noise is still there.

Another thing to add, I'm running my the volume pot on my crack full and use the volume controls on my computer. This is because there's some buzzing in the left channel if the pot isn't maxed out (which is a separate issue I'm working on).
I use Tidal to stream music. I have discovered that there is an option in the settings to allow Tidal to have exclusive control over the DAC. This setting bypasses the application volume control and instead my only way to control volume is with the amp. So, with this setting on I had to back down the volume on the crack 50-70 percent because it was insanely loud.
And magically the interference noise is gone. Seems to only be prominent when the volume is very high...

[Paul Birkeland]

I would recommend resolving the issue you're having with the amp before attempting to chase down other noise issues.

[elmoe]

Have you tried remounting the motherboard inside the computer? It sounds like it may be picking up fan vibration noise (fans spin faster when you're using the computer). Check the fans themselves also and make sure they are mounted tight to minimize vibration/clean them up and make sure airflow is unobstructed as much as possible. Since this seems to originate from the PC I would start there before worrying about cables etc.

[Deluk]

It's more usual to run the PC at full output and adjust the volume to your cans with the Crack. Running the Crack flat out, puts it into the area with all of the hum noise distortion etc even if these are generally low. I have an Asus sound card in my PC and usually juggle the PC and Crack volumes. The sound card is much quieter than the Crack but I prefer to adjust the PC to about 90% and that leaves me with a bit of leeway on the Crack for volume adjustment. I have not put resistors on the output but find it's OK, although I only have to increase the volume on the crack a small amount unless I'm really rocking out with my 600's.

[airofu]

I had the exact same issue with my crack, another amp was ok, but it was definitely some sort of ground noise from my PC via USB to dac then on to the crack that was being picked up. I got one of those cheap USB Isolator from ebay for $15, dead quiet now! But it did reduce my USB speeds and maxed my DAC to 96hz, still decent enough and now QUIET. I am thinking of getting the IFI iDefender 3.0 which apparently does the same thing with eliminating ground noise but keeps the speeds at USB 3.0

[JLDub]

Gentlemen, I have some AC line noise on my stock crack. I am running Ethernet powerline adapters so I pulled them and still a good bit of noise. I chalk it up to just noisy wiring in my house. Anywho, was going to first try something cheap like this: https://www.amazon.com/dp/B0009GH13Y
Curious, if that doesn't quite do the trick, would it be okay to plug the crack into a battery like this? https://www.amazon.com/dp/B01FWAZEIU
Not sure if the artificial sine waves these things put out would play nicely with the crack or if it wants something more "pure". Trying to keep it cheap before looking at Furmans more expensive conditioners like the PST-8. Thanks!

[Paul Birkeland]

How do you know the noise is from the powerline?

[JLDub]

I can hear it without the RCA cables plugged in, just the power. It stops as soon as I flip the power switch. Some of the tubes have a little noise, but it is a different kind of noise. This definitely sounds like mains. High pitching whining, etc.

[Paul Birkeland]

I would be sure everything is tight and well soldered on the amp, just to be sure.  Also consider plugging one of those 3 light outlet testers into your outlet to be sure it's wired properly. 

[JLDub]

Thanks for the troubleshooting tips! I will definitely give the circuit a once over with a fine tooth comb this weekend. I'd be surprised if I found something that's off. I took way longer to build the crack than needed because I have such obsessive tendencies LOL. It may not be super pretty, but all voltages measured correctly the first time to my relief.

Never considered using a line tester. Can definitely look into one of those or see if a neighbor has one I could borrow. What makes me think there is a lot of noise on the lines is that I had to move the powerline adapters around a bit to find a good outlet that isn't passing bandwidth at a crippled rate. Sometimes the amp is dead quiet, other times it will have a very noticeable high pitched whining noise that can be heard over some quieter tracks or just with power cable plugged in and nothing else.

If I end up needing to get some sort of conditioner or something do you think the crack would operate normally on one of those lower cost APC battery backups?