Getting Rid of Computer Hum?
Nov 21, 2008 at 5:06 PM Thread Starter Post #1 of 40

Traddad

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I have my music running from Media Monkey (I got sick and tired of wrestling with Foobar) to an Alien USB DAC. When I put the player on pause and turn the volume up to eleven
wink_face.gif
I get a very audible hum. I assume that is from the electronically noisy computer as it doesn't do it with the CD player.
All computer volumes are set at their highest.

Is there any way to get rid of this?

I really like the convenience of using the computer as a sourse for every day listening (especially since I'm moving to a single disc CD player) but It would be nice if I could make it as clean/good as practical.
 
Nov 21, 2008 at 7:14 PM Post #2 of 40

FasterThanEver

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Your hum may be caused by a ground loop. It is also possible that EMI from the computer is affecting the DAC.)

If you can provide some answers to these questions it would help me and maybe others provide advice.

1. Is the DAC connected to the computer with a Coax cable or an optical cable?
(In some systems coax may produce better sound but an optical cable isolates the DAC so that ground loops are eliminated.)

2. Are the DAC and the computer plugged in to the same electrical outlet? Are they plugged into the same power strip or surge protector?

3. What is the cable plugged into on the computer end? on-board sound? PCI sound card? USB to SPDIF converter?
(On-board sound or a dirt-cheap USB-SPDIF may not have good isolation.)

4. Does the hum change if you physical move the DAC to a different spot or rotate it? (The hum from a ground loop won't change if the DAC is physically moved but still plugged into the same SPDIF cable and electrical outout. Hum from EMI will be different for different physical locations.)

5. Try connecting the analog output from the PC to your preamp (or integrated amp. Whatever the DAC output is connected to.) Do you hear more or less hum than with the SPDIF to DAC to amplifier connection?

Bill
 
Nov 21, 2008 at 7:32 PM Post #3 of 40

krmathis

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Taking the whole system off-grid may help. If its humming caused by a ground loop that is.
Laptop -> DAC -> amplifier, all running on batteries (like my rig).
 
Nov 21, 2008 at 7:55 PM Post #4 of 40

Traddad

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The DAC is hooked up to the computer via a USB cable. That is also its power source for the DAC (USB power). While a ground loop might be possible, wouldn't it also be apparent when the CD was the music source?....the speakers are black all the way up with the CD as the source.

The chain goes thus:
Computer to USB powered Alien DAC via USB cable.
RCA outs on Alien Dac to my integrated amp (receiver). (My receiver also has the TV and CD hooked in)
Amp to speakers.
 
Nov 21, 2008 at 9:05 PM Post #5 of 40

FasterThanEver

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Further thoughts and questions:

If there is a ground loop, it is between the computer and the receiver (or the TV.) Is the computer plugged in to a different outlet or power strip from the receiver and CD player (and the TV.)

If your TV is connected to a cable TV coax cable or a satellite dish cable or an external antenna, that could be the culprit. Is the hum present if the TV is not connected to the receiver?

Ground loops are often subtle effects. They arise because 1) two components see different grou8nd potentials, 2) there is an electrical path between them and 3) some circuit is introducing the ground loop current flow into the audio signal.

You could expect to sit at your computer and apply reason to rule out suggestions. Or you could use reason to define experiments that you try to find the cause of the ground loop.

Bill
 
Nov 21, 2008 at 10:44 PM Post #6 of 40

Logistics

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Quote:

Originally Posted by Traddad /img/forum/go_quote.gif
When I put the player on pause and turn the volume up to eleven
wink_face.gif
I get a very audible hum.



Is this something you can hear while listening as loud as is comfortable to your ears? Because if not: /thread
 
Nov 21, 2008 at 10:45 PM Post #7 of 40

Traddad

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The computer is in another room entirely and on another circuit breaker.
The TV is connected to an antenna in the attic (separate than the FM) and the hum continues when I disconnect the antenna.
 
Nov 21, 2008 at 11:09 PM Post #8 of 40

Traddad

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Quote:

Originally Posted by Logistics /img/forum/go_quote.gif
Is this something you can hear while listening as loud as is comfortable to your ears? Because if not: /thread


Point taken but I still see it as a problem when no other source does it.
 
Nov 22, 2008 at 11:17 PM Post #10 of 40

Logistics

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"hay guys i never drive my car over the speed limit but i let a friend of mine drive it and he says there is a slight vibration at 200mph

how should i go about fixing that"

ಠ_ಠ

[size=large]ಠ_ಠ[/size]

[size=xx-large]ಠ_ಠ[/size]
 
Nov 23, 2008 at 1:49 AM Post #11 of 40

Traddad

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Quote:

Originally Posted by Logistics /img/forum/go_quote.gif
"hay guys i never drive my car over the speed limit but i let a friend of mine drive it and he says there is a slight vibration at 200mph

how should i go about fixing that"

ಠ_ಠ

[size=large]ಠ_ಠ[/size]

[size=xx-large]ಠ_ಠ[/size]



Hey, I own a Ferrari and it really should be a very good quality car but What do I care, I only commute back and forth to work in it.
 
Nov 23, 2008 at 8:50 AM Post #12 of 40

krmathis

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Simply don't turn the volume up to 11 without music playing.
tongue.gif

That way you will most probably never hear the hum.
 
Nov 24, 2008 at 8:08 PM Post #13 of 40

milkweg

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Quote:

Originally Posted by Logistics /img/forum/go_quote.gif
"hay guys i never drive my car over the speed limit but i let a friend of mine drive it and he says there is a slight vibration at 200mph

how should i go about fixing that"



Getting the wheels properly balanced will usually fix that issue.
 
Dec 27, 2008 at 4:49 AM Post #14 of 40

Traddad

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OK, enough with the snarky answers...I can hear it very well at levels that I listen at and it doesn't change with the volume. It is definitely from the computer (when I disconnect the computer the hum goes away) and It even hums when I'm playing CDs (not just audio files)
It's not a ground loop.
I'm using a USB DAC (powered by the computer) would Toslink do better? if so, what is a good, inexpensive Toslink > RCA DAC?

Dell Computer
Alien DAC
Onkyo TX-SV90PRO
 

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