TOPIC:

Is it needed? Or it does work also with USB cable with only data+, data- and ground connected?

Additionally, how many mhz is the clock installed on board?

Thank you,

Marco

UPPP

I revert myself: there is a 13mhz oscillator like usb streamer and it doesn't work with a usb cable without +5v connected.

Made a mistake...actually, cables without +5v connected DO work.

Hmm - I tried it as well and isolated pin1, but it didn't work. No sound.

Any idea?

Btw: if have a strong "plop" in my loudspeakers switching on my U-DAC8 (using a master/slave power switch)...this is why I'm asking.
Might a data only usb cable help?

Well, honestly I built myself the USB cable without connecting the +5v and following this guide (sorry it is in Italian):

www.diyaudio.it/content/149-DIY-Cavo-USB-HI-END

I think the issue is caused by the power switch: the u-dac8 must be switched on soon after you have pushed the button to start the pc (anyway during start-up and before accessing windows).

Dear Both,

Somehow we missed this post! Sorry to @ decapitate85 for the mishap.. Please use minidsp.desk.com (our tech support portal) if you need urgent help in the future.

@ Candrian,

While this seemed to have worked for decapitate85, we wouldn't recommend our customers to do so. This could lead to some issues and damage that would be outside the use of the product. In other words, you're on your own for this I'm afraid..

Plop at power up, this is very odd. Can you please share a bit more of your setup? Thanks.

DevTeam

In my configuration the U-DAC8 is taking power from a linear PSU and the usb cable is connected to a Paul Pang Audio Grade V2 USB card. No bump at all and no problem so far.

@decapitate85,
Cool, two weeks ago I ordered an USB cable from Italy with +5V and ground outside of the data cable.
Was it you?
Btw - just came back from a friend in Veneto where we setup his new environment (Klipsch RF7 + tube amp + ....)

@ devteam,
first of all my setup: Windows Home Server --> HTPC (fanless, Intel dh67cf board with IR) --> USB (special Italian cable ) --> U-DAC 8 --> DIY 5 channel power amp class D based on L15D modules --> Canton Reference / Vento 5.1 speaker
Front end is KODI / XBMC.
Power comes from a master/slave power strip, where the PC is the master and switches on all other devices as slaves

Here's the situation:
when the U-DAC 8 will be switched on as slave after the PC switches on I got 2 "ticks" when windows starts and another two "ticks" when KODI starts. Then I got a enormous "bang" like a snap or whip crack (my wife was about killing me). Also when I switch the freq from e.g. 48kHz to 96kHz I got the ticks.
When the U-DAC 8 is on permanent power I only get the "ticks", no bang.
I'm not yet using an USB isolator, which I ordered today.

Any other idea?
Thanks,
Christoph (very happy U-DAC 8 user)

p.s. just fyi: I'm using also the Audioquest JitterBug - better sound, but no influence on the "plops" and "bangs".....

candrian wrote:

@decapitate85,
Cool, two weeks ago I ordered an USB cable from Italy with +5V and ground outside of the data cable.
Was it you?
Btw - just came back from a friend in Veneto where we setup his new environment (Klipsch RF7 + tube amp + ....)

Good to know. Actually I did the cable for me, I'm not selling them.
Where are you from?
Unfortunately I don't have any idea concerning your bumps. Does it happen also with the "normal" usb cable provided with the U-DAC8?
Me I'm using CAD script to have better sound and close all the services unused.

So I'm from the north part of Bavaria (City of Aschaffenburg)....

I tried to make my PC as simple as possible. Running Windows 10 with a very clean setup:
- all unnecessary USB ports switched of in BIOS, internal audio (realtek) switched off
- boot with Kodi shell in registry (so no explorer coming up) --> very fast boot
- HDMI output to monitor

If you're interested my power amp is hidden behind the bookshelf: my power amp
(the first one)

I've also some strange effects from time to time: my power amp switches off exactly every 2 min for 10 sec. Then I need to unplug the U-DAC 8 for a while...then it works again. Hmm.... that together with the "plops".
EMV issue? USB ground / isolation?
I have no idea anymore.

Grazie Mille,
Christoph

Oh, now I remember. I tried for a couple of hours Windows 10 and had exactly the same problem. I was hearing buzz noise from tweeters and also bumped sometimes (sorry I forgot that). Returned back to win8.1 and everything set back to normal.

Grazie!

@devteam,
might that be an driver issues?
Is a new driver for Windows10 available?

Thanks,
Christoph

SOLVED

Now I finally isolated the +5V from the USB cable and I don't have the loud "bang" anymore.
Thanks to everyone.

Should I isolate the GND as well?
Instead of a ground USB isolator, which usually don't work with USB 2.0 high speed.