Humming sound from computer throught amp. Help?

[Kennydee]

Hi y'all,

I seem to have a bit of a humming problem coming from my computer to my amp/pre-amp in my new office. Here is what I have:
Onkyo Integra P-306RS preamp
Onkyo M-5160 amp
Yamaha T-80 tuner
JVC CD player
HP computer, model m9040n

I use the integrated sound card, original device on the mobo.
I had cheap wires from the computer to the stereo jack wall outlet (my computer is at the opposite side of the room to my audio devices. I ran a good quality stereo wire from one side of the room to the other, in the ceiling) so I bought sets of good sheilded stereo wires to replace them. This did not work. When I use my tuner or CD player there is no hum at all and sound comes clear and clean. I was wondering if by purchasing a decent audio card if this would considerably reduce or eliminate the hum. Any ideas? comments? I have a feeling that I am stuck with this hum.
Many thanks in advance.

Sorry for the fuzzy pics. Hard to do with Blackberry

 

[Shock]

I always suggest a sound card in almost every application, onboard sound can be nutoriously sketchy. I've had far too many problems that were simply fixed with a PCI sound card to ever recommend just using onboard sound.

Considering your other devices play fine, I would take a guess that that hum is a direct result in using onboard sound. Azuntech, Asus, Creative, they all make fantastic cards and usually have a budget minded card for a cheap upgrade.

 

[Kennydee]

I always suggest a sound card in almost every application, onboard sound can be nutoriously sketchy. I've had far too many problems that were simply fixed with a PCI sound card to ever recommend just using onboard sound.

Considering your other devices play fine, I would take a guess that that hum is a direct result in using onboard sound. Azuntech, Asus, Creative, they all make fantastic cards and usually have a budget minded card for a cheap upgrade.

Thanks Shock! You know I took extra care to segregate/separate/isolate the electrical and audio wires so I would not have that problem. Yeah, a dedicated sound card does make sense. I will try that and let you know how that went.

Thanks again Shock.

 

[s162216]

Check your southbridge temperature - humming or skipping sound can be one of the first signs of southbrige overheating as it controls onboard sound, if it feels quite warm to touch then it might need cooling or it may just go away on its own. Hows the airflow into the computer

Are you doing any overclocking on that computer as that can increase the chances of this?

Be warned though, the HTPC on my sig is now dead due to the southbridge spectacularly failing. First I started getting what you have, a hum/buzz sound just on the one channel of the reciever/amp, just when the computer is connected. Next the computer just started randomly crashing and restarting, and then to take the biscuit:

Beeeeeeeeeeeeeeeeeeeeep "IDE Controller Failure" on startup screen.

I managed to get it to start a couple of times but it never worked again so I am back to where I was in October, no HTPC due to hardware failure. I am such an unlucky guy with computers -they just seem to fail around me! Ironically found out today that Nforce2 motherboards are notorious for failing like that when the southbrige overheats.
For my 'new' Nforce2 HTPC I am taking no chances and getting as much quiet cooling as possible.

 

[Kennydee]

Thanks s162216,

Good point on the southbridge temp. I actually checked all vitals on my machine just a week ago and all seems fine. I have to admit that there's not much room in this small box. In fact, there is a lot less since I changed my video card (Gforce 8800 GTS) from the onboard video controler when I bought the machine. Not much airflo. I'm seriously thinking of building myself a new machine with a bigger box and newer tech. Just installed Win7 64b about 2 weeks ago. I need to clean the insides of this thing soon I guess. Well now thaks to you I may end up spending an extra 1000 on a new computer. GEEEE!!!

 

[Kennydee]

Hey! just looking at my motherboard's specs and I never realized that I have a coax SPDIF port out. I'll try using this instead to see if there are any difference. I can get a Coax to RCA L+R splitter cable right? Could that make a difference or if there is humming through regular line out I'll get the same through coax?

 

[bandphan]

Is the computer on the same circuit as a dimer a variable speed fan switch?

 

[Kennydee]

Is the computer on the same circuit as a dimer a variable speed fan switch?

No and no... In fact I added a dedicated power outlet for the computer and audio equipment. The only stuff connected to this line is the computer, audio as shown in the pics and a light switch (not dimmer) for my closet.

 

[Kennydee]

I'm thinking that Shock may be right about the dedicated audio card as opposed to the audio controller on the mobo. They're not that expensive so I'll get one by the weekend and try it out. Together with a good cleaning, hoping the southbridge is not overheating. I did not overclock my machine either so that's not it.... I like playing golf online and listening to music but the hum is quite a nuisance.

 

[Nugu]

Onboard sound cards are highly susceptible to the noise in a PC and that's likely what you are hearing. (I could hear interference from my RAID array when I used the headphone jack, literally I heard the heads reading the platter)

Switching to a digital output so the analog conversion is done outside the PC will more than likely fix this. I mean, may as well use your expensive home theater gear to decode the audio instead of spending more. (Worked for me)

 

[s162216]

Onboard sound cards are highly susceptible to the noise in a PC and that's likely what you are hearing. (I could hear interference from my RAID array when I used the headphone jack, literally I heard the heads reading the platter)

Switching to a digital output so the analog conversion is done outside the PC will more than likely fix this. I mean, may as well use your expensive home theater gear to decode the audio instead of spending more. (Worked for me)

With the problem I mentioned about my HTPC that killed it, I was using coax but still got the hum. This could have been because I was using the Dolby Digital Live encoding with the soundstorm so any noise was getting encoded as well.

 

[Kennydee]

Switching to a digital output so the analog conversion is done outside the PC will more than likely fix this. I mean, may as well use your expensive home theater gear to decode the audio instead of spending more. (Worked for me)

I do use my computer to connect to my HT via ethernet. My TX-NR3007 receiver and home network does a darn good job at that.
But, here is a question then, Can I use the computer's digital out to connect to my older preamp in my office? My pre will take stereo inputs, no digital in. So, can I use digital out, split to stereo jacks and then feed the pre? Does that make some sense?

 

[s162216]

No as the digital out supplies a digital PCM, Dolby Digital or DTS stream - to decode it into analogue to be amplifed you'll need to use a receiver with a digital in.

One point about using the digital out is that only DVD's and CD's will play through it, no MP3's etc as they are not in a compatible format that the reciver can understand. The only way to get these to play through the reciver is to use Dolby Digital Live or DTS Connect to encode any sound to Dolby Digital or DTS

 

[sholling]

No as the digital out supplies a digital PCM, Dolby Digital or DTS stream - to decode it into analogue to be amplifed you'll need to use a receiver with a digital in.

One point about using the digital out is that only DVD's and CD's will play through it, no MP3's etc as they are not in a compatible format that the reciver can understand. The only way to get these to play through the reciver is to use Dolby Digital Live or DTS Connect to encode any sound to Dolby Digital or DTS

I'm confused. I play flacs (uncompressed audio) through the digital output of my computers sound onboard sound system all the time. It's connected to the digital-in corrector on my receiver. Whatever you use for music player software handles the conversion to a format that the onboard sound card can understand and the soundcard will then output the signal in a format that the receiver will understand - correct me if I'm wrong but I believe that's usually PCM or DTS. That's pretty much SOP for any sound card.

 

[sholling]

Switching to a digital output so the analog conversion is done outside the PC will more than likely fix this. I mean, may as well use your expensive home theater gear to decode the audio instead of spending more. (Worked for me)

I do use my computer to connect to my HT via ethernet. My TX-NR3007 receiver and home network does a darn good job at that.
But, here is a question then, Can I use the computer's digital out to connect to my older preamp in my office? My pre will take stereo inputs, no digital in. So, can I use digital out, split to stereo jacks and then feed the pre? Does that make some sense?

What you could do is use an external USB sound card to drive the preamp. These are getting pretty cheap and will get the digital to analog conversion outside of the PC.

 

[s162216]

Only certain file formats will do that - flac will be decoded to PCM for instance but it depends on the player.
This is the reason why pc game audio has not been able to be sent down the digital until recently when they have started to be encoded in dts or dolby digital.

 

[Kennydee]

What you could do is use an external USB sound card to drive the preamp. These are getting pretty cheap and will get the digital to analog conversion outside of the PC.

Thanks Sholling,

I went on eBay to see these things. They are cheap. Lots cheaper than I expected in fact. Are there any brands that offer a high quality product? I have no clue what is good or what is "buyer beware".

Thanks again

 

[Kennydee]

Just started reading on external and internal sound devices. What I can see in most cases are devices that will give you either a 2.1, 5.1, 7.1 surround effect. I just need analog (stereo L+R). I have 4 in wall speakers in my office connected to my Onkyo stereo audio system. I don't mind paying for something that will give me perfect sound and in this case, sound without the hum. Is there such a thing as a high end audio card for PC that would deliver a high quality stereo L+R signal without the hum? I'm getting more and more confused.

I do appreciate everyone's comments.

 

[Nugu]

To keep it simple, the hum comes from electronic interference in your computer (barring equipment failure). Yes you can probably solve the problem by getting a new sound card (X-fi series seems worth looking into) but it is by far better to separate the Analog conversion from your computer.


A reasonably priced external solution is a Zero DAC/AMP (simple terms - a external sound card with a small amplifier built in) off ebay (chinese, but very high quality) for about 140-200$. It is a solid state Headphone amp that can also function as a Stereo pre-amp and has a good DAC and opamps in it which can also be changed if you want to alter the sound or upgrade the DAC/opamp.

Since you don't seem to use a receiver you may also consider that instead, esp one with pre-outs if you want to continue using external amps. That won't run you much more than a Zero.

However if you just want to get rid of the hum the USB thing sholling recommends will probably work, I just can't attest to the quality of any DAC in them.


And as far as digital output from a computer, generally all sound is converted to 2 channel PCM (including games, mp3, etc.) if it isn't DTS or AC3 (which still has to be set to 'pass-through' in the program so it isn't down mixed to stereo). Again this depends on the sound driver used for your card/onboard sound. I'm sure there are some exceptions that don't default this though.

 

[Kennydee]

Thanks Nugu, Saw it on eBay and will purchase one in the next few days. I'll report back when installed and tested.