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Old September 2nd 18, 02:10 AM posted to alt.comp.periphs.mainboard.asus
Tater
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Posts: 10
Default P8Z68/GEN3 Deluxe Noisy USB Bus

I was trying to listen to some MP3s on my PC via iTunes, and suddenly
I was like "What the heck - this sounds like crap". I was getting
random clicking and crackling noises. It basically sounded like I was
playing back a badly worn LP.

First I tried the same track several times in a row and confirmed that
the clicks and pops were random - not in the same location in the
track. I tried different tracks from other albums - same story.

Then I turned to hardware troubleshooting - before I tell you about
that let me describe the sound system on my computer:

It's PC to USB DAC to tube preamp to amplified speakers. I am not
using the onboard sound on the motherboard. The USB DAC (digital to
analog converter) is a little gadget like a USB thumb drive that plugs
into a USB port on the back of the PC and outputs an analog signal on
a standard 1/8" phone jack. The tube preamp provides volume control
(and that "good old tube sound"), and the speakers each have their own
amplifiers built in.

First thing I thought was I had a bad connection somewhere. I
unplugged and reseated the DAC and all the analog connections. Didn't
help.

I ruled out a bad speaker because the noise was occurring in both
channels.

Next I pulled out an older DAC and swapped the DACs out. Didn't help.
I moved the DAC to two other USB ports - didn't help.

I moved the DAC to my add-in Inateck USB 3.0 board (I'm not using the
onboard USB 3.0 on this motherboard). This seemed to make the noise
even worse.

To eliminate the tube preamp as a source of noise I disconnected the
preamp and speakers, and plugged a set of headphones directly into the
jack on the DAC. I Still heard the same noises via the headphones.

So now I've isolated the noise all the way back to the PC itself - my
troubleshooting has eliminated anything external to the PC as a
possible source of noise.

I suppose it might be a noisy power supply (and I do have a spare) but
that's a lot of work to change out unless I truly have to.

The only other thing I could think of trying at this point was to
remove the DAC and activate the onboard sound chip on the motherboard,
so that's what I did. Asus had a massive Windows 10 audio driver on
their web site that came out two years ago - but I decided to let
Windows try and install the sound device by itself, figuring I'd
probably get a more up to date driver that way. It did find a driver
for it - it's a pretty basic driver, but I don't need any fancy
features. Pure unadulterated two channel sound is all I was looking
for.

So I hooked up my preamp to the onboard sound port and played an MP3.
Sounds fine, zero noise. I'm not going to say it's as good as the USB
DAC, but it sounds a heck of a lot better than I was expecting.

This leaves questions though. If the power supply was noisy,
shouldn't that noise have permeated the onboard sound system as well?

What is the nature of this noise I'm hearing through the USB DAC? If
there is random noise on my USB bus, I would think I'd be at risk for
corrupted data on USB devices like my big backup drive or my USB thumb
drives?

Any advice is appreciated!

Configuration:

Asus P8Z68 Deluxe/GEN3 motherboard
4x4GB Corsair Vengeance LP DDR3 1600 RAM
Intel i7-2700K CPU
EVGA Supernova 850 T2 power suppy
EVGA GTX 970 FTW+ 4GB video card
SanDisk Extreme Pro 480GB SSD boot drive
2x1TB Western Digital Black data drives
Western Digital 8TB My Book Duo USB backup drive (in Raid 1)
Antec P280 case
Noctua CPU cooler and 3 Noctua case fans
Inateck KTU3FR-2O2I add-in USB 3.0 card
Pioneer 16X Blu-ray burner
Windows 10 Pro version 1803
Meridian Explorer 2 DAC
ifi iTube preamp
Paradigm Shift A2 speakers

Thanks in advance.

Jerry