[AndyDParticipant]

Hi Mike and others,

My earlier comment on doing a full hard board reset is just to make sure all the board setting would be at default.
Do the reset and nothing else then bring up the master fader to see what the noise is like with no inputs connected to the mixer. I tried this as you suggested, but no change…noise still coming out to Main LR after audio played (even after stop and unplugged ST3 or input 15 and 16).

After exhausted all my options and talked to a few friends of mine and with all your suggestions to get this to work. Unfortunately, I have finally decided with at least 95% confident that I have a bad unit. So I took it back to GC and exchange the unit for another Qu16.

The New QU16 works wonderfully.

I would like to end this thread with a result of a bad unit.

Thanks everyone.

[AndyDParticipant]

Try getting a 3.5 to 1/4” Y cable and attach to st1 or st2. I believe I’ve read posts here of the usb connector introducing noise. Mike is correct…I do not have any USB. I do have a 3.5mm Y to dual 1/4 into 15&16

[AndyDParticipant]

Hi Mike,

Do you have the K10 set for mic or line input, it should be line? YES – both inputs are LINE
(Each input has a line level input setting)

Do you get the noise with nothing connected to the mixer except the outputs
connected to the speakers? When the system is completely off for awhile and turn back on with k10s not much noises at all. After play music from itune for 5-10mins, at the beginning (i stopped the music to track the noise) the noise is comfortable later on the noise getting worse ( i can hear from 6 ft away). I unplugged the input 15 and 16 and their faders and Main fader all down, still the worse noise. Raise the Main fader to max…higher noise lvl output.

Does the noise level change when you turn the master fader up and down? So after Qu16 warmed up, I unplugged line 15,16 and their faders down. When I use Main fader up and down, the noise will increase and decrease as I use the fader.

Do you get the same noise if you connect the speakers to one of the mix outputs? Interesting questions, thanks for asking. I did this test before and here the result: Main L&R, Stereo Mix 10&9 have the same noise lvl. Stereo Mix 8,7, Mono 6 to 1 are very quite.

Do you hear the noise in headphones plugged into the mixer? Sorry, I do not yet have a headphone 1/4 to test this part.

Make sure you XLR cables do not have pin 1 tied to the outer shell of the connector, some of the import budget cables come wired that way. One set is Live Wire from Guitar Center, the other Set is Mogami GOLD.

I would describe a 60hz sound more like hummmmm. So this part is what confused me. If I move my ears near K10s, I hear hummm from the low part of k10. Pink or random Pink noise from the top part. But from the distance I would say, the PINK noise is much more dominion

Post a link to a clip of the audio or even a cell phone video of it. I will my best to make this part happened.

” I LEFT THE SYSTEM IDLE FOR ABOUT A FEW MINUTES, NO NOISES COMING OUT”
That comment makes me think the K10 has a signal mute if it does not detect audio
input level after a few minutes. You are absolutely correct. I contacted QSC tech support, they said if you have a DIRECT connection of Line, Mic, 3.5mm into the K10s and you hear no noise or hummm the K10s are working perfectly fine.

Without a transformer isolation there’s 50 50 or better chance that when you connect part of a video system to a sound system that you will get hum, buzz or noise of some type. Do you have a link to one of the product you recommanded..see if I can get them local or from Amazon.

Thank you so much

[Author]

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