Occasional annoying hum. Looking to circumvent with DAC/amp.

[yemar]

Hello Everyone,

I have this incredibly annoying hum once in a while that I can hear through both my 2.1 setup and headphones from my desktop. Right now I have onboard sound that uses Realtek ALC889. I would like to get a DAC/amp combo for under $100 (my wife and I are both teachers without a huge amount of disposable income). I need to connect to both my 2.1 powered system (it has RCA and 3.5 mm inputs) and my Philips SHP9500 (32 ohm). I listen to a lot of music (huge variety), play games, edit recorded lectures, and watch some TV/movies.

I have a separate problem where I constantly have to reset my webcam because the sound gets screwed up and makes me sound like a chipmunk. It would be nice to have a mic input as well so I can stop using my webcam mic. I have read about the Sound Blaster Omni, which people do not seem to care for very much. I do like that it has what people say is a decent built-in mic, as well as a mic input (ADC I imagine).

Any and all suggestions are welcome. Size makes no difference (it's for my desktop), and I would like to avoid batteries. Thank you.

 

[adw]

Hum can be caused by the 3.5mm jack used for speakers or headphone is not perfectly plugged.

I assume either bad line out soundcard connector, cable not perfectly plugged/bad cable or the speaker is in parallel with headphone. How do you connect your headphone? Did you unplug the speaker input cable and plugged in headphone? Did you use 3 connector 3.5mm jack or 4 connector 3.5mm jack, as this also can cause hum if you use 4 connector 3.5mm jack on desktop, because desktop soundcard output have other jack for microphone.

As for the chipmunk sound, I think it is not related to soundcard, DAC or ADC, since the connection is made by single USB cable, both for audio and video.

If you able to solve the webcam issue and humming, you can save money if you buy external microphone, plugged to microphone on the microphone on the microphone jack.

Desktop onboard or add-on soundcard have color coded output. Make sure plug the correct cable to correct connector.

For color code soundcard output, you can refer to mainboard or computer manual.

Maybe this link helps:
https://www.hobby-hour.com/electronics/sound-card-color-code.php

 

[AnalogSteph]

Can the hum be correlated with anything? Does it also occur when no sound is playing?

I have a hunch that there might be a deeper-rooted problem e.g. with excessive DPC latency here. You don't have an nVidia Pascal (GTX10xx) series graphics card? Those were quite notorious in this regard. Update graphics drivers (or if you have something old like GTX7xx, try the old 347.88), check for availability of a more current BIOS, and download LatencyMon and see what that has to say.

What are the components of the system anyway? I hope not to be seeing some dodgy power supply...

I have some ideas for sound hardware, too, but there would be little point in throwing money at the problem if it's not addressing the actual root cause.

 

[Speedskater]

Watch to see if it's correlated with turning on/off of appliances, high tech lighting, HVAC or other entertainment/data systems.

 

[yemar]

Can the hum be correlated with anything? Does it also occur when no sound is playing?

I have a hunch that there might be a deeper-rooted problem e.g. with excessive DPC latency here. You don't have an nVidia Pascal (GTX10xx) series graphics card? Those were quite notorious in this regard. Update graphics drivers (or if you have something old like GTX7xx, try the old 347.88), check for availability of a more current BIOS, and download LatencyMon and see what that has to say.

What are the components of the system anyway? I hope not to be seeing some dodgy power supply...

I have some ideas for sound hardware, too, but there would be little point in throwing money at the problem if it's not addressing the actual root cause.

My setup is:

• EVGA Z68 FTW mobo (updated as it gets BIOS, but the mobo is getting a little long in the tooth)
• EVGA GTX 1060 6GB
• Corsair HX 750 power supply
• Intel i7 2700k
• SSD and HDD
• case fans

I haven't heard the hum in a few days, although when I heard it, there was nothing playing. I can't recall if it is correlated with other electrical activity in the house (I have four kids and a wife all doing things). I will pay attention to that next time. I have the 2.1 powered sub plugged into the rear panel line out with a 3.5 mm cable. I can get the speakers to hum when I jiggle the cable, but it seems fully inserted now. I feel stupid, but I can't remember if the headphone hum was when I had it plugged in to the headphone jack on the speaker, or the headphone jack on front panel.

The logitech webcam I have is known for screwing up the voice sampling rates. I'm pretty sure that's why I sound like a chipmunk and have to reset it often.

 

[amanieux]

check that your ac power plug has a ground pin connected

 

[Willem]

The hum does indeed seem to be a plug that is not connected properly, but I would not know for certain, of course. Can you try a different cable from the computer to the amplifier? Whether an external DAC/headphone amp will make a meaningful difference in sound quality depends a lot on the rest of the system. We decided that it was worth using an external DAC, but since then computer audio has been getting better, particularly I think with desktops. The computer's built-in headphone amp is probably a weaker link than the DAC.
My wife and I both now do a lot of online teaching and videoconferencing, and we use cheap Logitech webcams without any problems. We managed to buy a CD270HD before stocks ran out and it is more than good enough. My wife needs the best gear we have because she teaches so much, so I am using her old C210 webcam while she uses the C270. She now also has two screens and already had a very fast desktop computer. But even pretty basic webcams produce quite decent video, and right now you don't want to overstretch videoconferencing systems by using higher resolutions anyway. Once supplies will be more generous again, and prices will have returned to normal, we will buy another better webcam, but what we have now does the job. Audio is more important, and even though the webcams produce somewhat decent sound, we also concluded that an external microphone is far better because it avoids a bathroom sound and excludes all extraneous noise (the audio from students's laptops is often terrible). So I gave my wife the Sennheiser me3 (plus external ADC) that I had been using for speech recognition software. Using such a microphone close to your mouth really improves the sound that students can hear. That Sennheiser is expensive, but I have noticed that even pretty basic usb headsets with microphones on a short boom are perfectly fine. Speech recognition is a far more demanding application than video conferencing, but I have had great advice from https://www.speechrecsolutions.com/