MiniDSP 8x8 in 1U Rack Enclosure

[grahamgraham]

Hi all!

I wonder if anyone might be able to answer what might be a couple of daft questions about putting my 8x8 in a metal rack case.

My 8x8 has been sat on my shelf working for a year now and I've had issues with noise from my computer getting through to the audio. I hear discs spinning up and a ground loop whine. I thought the next step in solving this problem is to case up the MiniDSP and eliminate potential causes one by one. So...


1. When I mount the board to the case do I want to use metal hardware to couple the board to the metal for shielding?


2. If I do the above can I mount the DC power socket straight in to the metal without isolating it?


3. Are there any recommended things I should do in the process of what is seemingly a simple mounting?


This is the case I have ordered:
https://cpc.farnell.com/penn-elcom/...1u-220mm-deep/dp/EN55271?MER=sy-me-pd-mi-alte


Cheers!


http://www.minidsp.com/images/documents/miniDSP 10x10 Hd and 8x8 kit User Manual.pdf

 

[tommus]

start here!

Audio Component Grounding and Interconnection - diyAudio

 

[Rick PA Stadel]

Sure hope a properly grounded case solves all your problems, but ...

The disk-spin-up and whine sounds are, unfortunately, fairly common among certain lines of laptops and even some desktops. One of my favorite older units was incorrigible -- even with isolation transformers -- yet played fine just by unplugging the power brick and running on the internal battery.

Cheers

 

[Fenalaar]

Minidsp has availble a ready-made all-steel enclosure for the 8x8.

Enclosures : miniDSP 2x8/8x8 Box

You might want to consider getting a toslink for you PC, and connect your pc through an optical cable. USB Audio Streaming : USBStreamer Kit

Johan-Kr

 

[grahamgraham]

start here!

Audio Component Grounding and Interconnection - diyAudio

Thanks, man. SO, signal ground and power ground need to stay separate? UNfortunately the MiniDSP mixes the two from continuity testing. Is there anything I can do?

Sure hope a properly grounded case solves all your problems, but ...

The disk-spin-up and whine sounds are, unfortunately, fairly common among certain lines of laptops and even some desktops. One of my favorite older units was incorrigible -- even with isolation transformers -- yet played fine just by unplugging the power brick and running on the internal battery.

Cheers

Yes, it's very frustrating. I might at some point move the an SSD to eliminate just one of the noises!

Minidsp has availble a ready-made all-steel enclosure for the 8x8.

Enclosures : miniDSP 2x8/8x8 Box

You might want to consider getting a toslink for you PC, and connect your pc through an optical cable. USB Audio Streaming : USBStreamer Kit

Johan-Kr

Yes, I definitely have and will be looking to do that. I need the Digi-FP module for input and I can take TOSlink out of my Xonar U5. It's a shame I can't get 8 digital inputs in to the 8x8 board for my surround!

 

[KaffiMann]

USB soundcard and USB isolator.
Hifime High-Speed USB Isolator

 

[grahamgraham]

USB soundcard and USB isolator.
Hifime High-Speed USB Isolator

I have a dc-dc isolator between the usb power lines of my computer and the sound card. The screen is still connected. One of these:

TBA 2-0511 | TRACOPOWER TBA 2 2W Isolated DC-DC Converter Through Hole, Voltage in 4.5 → 5.5 V dc, Voltage out 5V dc | RS Components

Does the unit you have linked offer any extra isolation? Cheers for the suggestion.

 

[grahamgraham]

I've not done any metal work like this before and I cocked up the holes for the rca sockets so badly I had to cut a much wider hole for the Phoenix connectors as well.

Have I ruined all screening properties that the case will give me with these wide holes?

 

[KaffiMann]

Does the unit you have linked offer any extra isolation?

It's not only the power that's "dirty" on a computer, the noise seeps into the data bus as well.
It's not always the right solution, but I haven't used a PCI slot soundcard for well over a decade because of all the noise inside PC's.
Just sayin' it's hard to deal with, so part of my solution is using external solutions with balanced interconnects. Much better now, but seems there's always another step to do in the battle against noise.

 

[grahamgraham]

It's not only the power that's "dirty" on a computer, the noise seeps into the data bus as well.
It's not always the right solution, but I haven't used a PCI slot soundcard for well over a decade because of all the noise inside PC's.
Just sayin' it's hard to deal with, so part of my solution is using external solutions with balanced interconnects. Much better now, but seems there's always another step to do in the battle against noise.

Thanks man, I feel the same. When I wrote music I had internal soundcards and didn't have a lot of joy til I moved to a laptop with USB interfaces like the Mbox and Edirol stuff. The quest goes on...

 

[grahamgraham]

It isn't the prettiest thing I've made but it's perfectly functional. There was A LOT of hand filing done.

Now I am getting the same stinging power arc (?) from the MiniDSP enclosure that I get from my computer case if I lightly touch is with sensitive skin. No improvement on noise but that's one potential problem taken care of.

I wonder if the stinging arc from both cases is due to poor grounding or something from my computer PSU? I use a Lenovo ThinkCentre E73 Core i5 with maxed out 16gb RAM. A budget machine.

Both Xonar U5 and MiniDSP 8x8 are connected via USB to computer constantly and audio is connected between them. Potential loops?

 

[Fenalaar]

The stinging can be a indication of a ground fault problem. You’ll need to check that out, as that can turn into a possibly fatal problem. Is your fuse box equipped with ground fault indicators? Are you running stuff on different circuits?

If you have a voltmeter, check the voltage between the computer case and earth.

Johan-Kr