The No.1 Website for Pro Audio
 All  This Thread  Reviews  Gear Database  Gear for sale     Latest  Trending
Bleed from my computer power to my console/monitors
Old 28th March 2019
  #1
Lives for gear
 
Septik's Avatar
Bleed from my computer power to my console/monitors

I have some unpleasant noise coming through my console master any time my computer is powered on. It is very faint, have to have my monitoring at optimal volume to hear it faintly. I can hear it on my monitors and headphones equally. Is this a common type of thing? It vanishes when I turn my computer off, and it gets louder when my computer is doing lots of processing. Can you guys recommend anything I can do to deal with it? It is making my critical mixing fairly difficult..
Old 29th March 2019
  #2
Lives for gear
 
Richard Crowley's Avatar
 

This is rather a common problem. You are lucky it is such a low level.
The most common problem is with laptop computers and using the internal audio interface.
It would be very helpful to know what computer you are talking about.
And how the computer is connected to your audio gear (if it is?)

If you are using a laptop, do the symptoms change if you operate from batteries vs the mains power brick?
Do the symptoms change with the location of the computer? What other things affect the noise level?
Old 29th March 2019
  #3
Gear Addict
 
audiospecific's Avatar
 

That is why I stayed away from usb, firewire, thunderbolt interfaces because they share grounds with the computer.

ADAT, MADI, and ethernet (dante, avb, etc) are electrically isolated from the computer and these are the technologies I recommend for computer based tracking.
Old 13th June 2019
  #4
Lives for gear
 
Septik's Avatar
Quote:
Originally Posted by Richard Crowley View Post
This is rather a common problem. You are lucky it is such a low level.
The most common problem is with laptop computers and using the internal audio interface.
It would be very helpful to know what computer you are talking about.
And how the computer is connected to your audio gear (if it is?)

If you are using a laptop, do the symptoms change if you operate from batteries vs the mains power brick?
Do the symptoms change with the location of the computer? What other things affect the noise level?
Sorry for the late reply, I lost track of the thread! I am working with a hackintosh desktop machine. I also have some external hard drives attached. My interface is an antelope orion 32 connected over USB. The noise only comes in when the computer is powered on. All of my gear is connected via furmon power distributors all attached to the same wall plug.
Old 13th June 2019
  #5
Lives for gear
 

Three main things to try.

First physically move your computer tower away from the audio interface. A poorly shielded/grounded computer case will emit RF into the audio device where it gets amplified like a radio.

Second, to combat any noise from coming in on the power supply cables, get yourself some inexpensive computer style power strips.
These have enough filtering to prevent this kind of noise from leaking through the AC and ground connections. No need to spend allot of money on high end AC filtering. The $10 ones will do the same job here.

Third you can buy some ferrite beads. https://www.amazon.com/Pienoy-Noise-...90641507&psc=1

You can clip these onto your USB, audio and power cables to prevent noise from riding in on the cables and getting amplified. you may have to go into the computer tower and clip these onto power cables and whatever you think might be allowing the noise to leak over to the USB port in a trial and error basis till you minimize the noise created. As a tech I used to use an RF generator connected to a coil which I'd use as a probe inside audio amplifiers and guitars. When I'd hear the noise levels go up it was a weak spot in the circuit or wiring and I'd beef up the shielding to prevent radio/magnetic/AC waves from leaking in to the audio path. You can do the opposite by adding those beads and clipping them onto different wires till the noise is eliminated.




Old 14th June 2019
  #6
Gear Addict
 
audiospecific's Avatar
 

Quote:
Originally Posted by Septik View Post
Sorry for the late reply, I lost track of the thread! I am working with a hackintosh desktop machine. I also have some external hard drives attached. My interface is an antelope orion 32 connected over USB. The noise only comes in when the computer is powered on. All of my gear is connected via furmon power distributors all attached to the same wall plug.
if you really want to use the usb port, try taking a usb port on a card bracket, and lifting the gnd and the 5Vcc pins out of the header connector and tape them off. You should only need the + and - data pins. because it shouldn't have to use the dirty usb power. However, if the noise is coming from the chassis ground, it wouldn't be interrupted. So this might be a fix for 70-90% of the time....

You could try a different computer power supply.

Or connect a madi interface to it and optically isolate the unit.

There are isolator, linear power substitution, devices out there too, but I would skeptic of the devices offered in the audiophile channels because they just discovered crappy usb port solutions. Industrial USB isolator has been a developed product for a couple of decades.
Old 14th June 2019
  #7
Gear Maniac
 
Dan O's Avatar
 

Quote:
Originally Posted by audiospecific View Post
That is why I stayed away from usb, firewire, thunderbolt interfaces because they share grounds with the computer.

ADAT, MADI, and ethernet (dante, avb, etc) are electrically isolated from the computer and these are the technologies I recommend for computer based tracking.
This was new info for me. Very interesting, are you sure about this? I thought all interfaces shared ground. I've got a star grounding wiring going in my studio but I am a bit worried about what will happen when I get to connecting the thunderbolt interface I intend to buy.
Old 14th June 2019
  #8
Lives for gear
 
Richard Crowley's Avatar
 

Quote:
Originally Posted by Dan O View Post
This was new info for me. Very interesting, are you sure about this? I thought all interfaces shared ground. I've got a star grounding wiring going in my studio but I am a bit worried about what will happen when I get to connecting the thunderbolt interface I intend to buy.
MADI over copper uses a connected ground and is not isolated.

However MADI over fiber is optical and clearly isolated (as is ADAT).

Ethernet is isolated by definition, using digital transformers at both ends.

Thunderbolt over copper uses shared ground. But although Thunderbolt (originally called "Light Peak") was designed for optical fiber transmission, the copper version was better performing than designers anticipated, and there are few (if any?) optical versions of Thunderbolt out there.

Since you didn't mention which "thunderbolt interface you intend to buy", we can only speak in generalities.
Old 14th June 2019
  #9
Gear Maniac
 
Dan O's Avatar
 

Quote:
Originally Posted by Richard Crowley View Post
MADI over copper uses a connected ground and is not isolated.

However MADI over fiber is optical and clearly isolated (as is ADAT).

Ethernet is isolated by definition, using digital transformers at both ends.

Thunderbolt over copper uses shared ground. But although Thunderbolt (originally called "Light Peak") was designed for optical fiber transmission, the copper version was better performing than designers anticipated, and there are few (if any?) optical versions of Thunderbolt out there.

Since you didn't mention which "thunderbolt interface you intend to buy", we can only speak in generalities.
Well I'm looking mostly at the antelope ORION or perhaps MOTU 16A or Lynx Aurora but the specs vs price seems very good on the ORION.
Old 4 weeks ago
  #10
Gear Addict
 
audiospecific's Avatar
 

Quote:
Originally Posted by Dan O View Post
This was new info for me. Very interesting, are you sure about this? I thought all interfaces shared ground. I've got a star grounding wiring going in my studio but I am a bit worried about what will happen when I get to connecting the thunderbolt interface I intend to buy.
The A/D converter side usually shares its unbalanced analog ground (virtual ground, vref) with the digital ground. There are a few conversion circuits (like Burl, JCF, DAD) that are transformer isolated. There are ones too like metric halo that deploy transformer coupling with a heavily filtered usb port that is 99% effective and it only measurable in those systems.

If you deploy electrically isolated technology (MADI, ADAT, and Ethernet (like Dante)) for the digital I/O side, the computer noise will not get referenced to the audio signal.

Unfortunately, the copper based thunderbolt was adopted because its the cheaper to build and greater profit margin are obtained compared to the Optical Thunderbolt that is electrically isolated.
Old 4 weeks ago
  #11
Lives for gear
 
Richard Crowley's Avatar
 

Quote:
Originally Posted by audiospecific View Post
Unfortunately, the copper based thunderbolt was adopted because its the cheaper to build and greater profit margin are obtained compared to the Optical Thunderbolt that is electrically isolated.
Perhaps. But there is the much more practical issue of power. You can't transfer power over an optical link.
Old 4 weeks ago
  #12
Gear Maniac
 
Dan O's Avatar
 

Quote:
Originally Posted by audiospecific View Post
The A/D converter side usually shares its unbalanced analog ground (virtual ground, vref) with the digital ground. There are a few conversion circuits (like Burl, JCF, DAD) that are transformer isolated. There are ones too like metric halo that deploy transformer coupling with a heavily filtered usb port that is 99% effective and it only measurable in those systems.

If you deploy electrically isolated technology (MADI, ADAT, and Ethernet (like Dante)) for the digital I/O side, the computer noise will not get referenced to the audio signal.

Unfortunately, the copper based thunderbolt was adopted because its the cheaper to build and greater profit margin are obtained compared to the Optical Thunderbolt that is electrically isolated.
Too bad. Thunderbolt seems quite good otherwise.
Old 4 weeks ago
  #13
Gear Addict
 
audiospecific's Avatar
 

Quote:
Originally Posted by Dan O View Post
Well I'm looking mostly at the antelope ORION or perhaps MOTU 16A or Lynx Aurora but the specs vs price seems very good on the ORION.
I haven't found really any data to investigate the weaknesses of the Antelope Orion, but looking at industry practices with high channel count conversion chips, the balanced line methodology deployed in them add the power supply noise to the signal. So your mileage may vary like the usb interfaces that are prone to pick up noise from the computer.

Does that mean its not good? it depends. High channel count A/D conversion IC can deployed nicely, which is properly executed n things like the Dante Snake boxes and AES50 (twisted pair MADI over ethernet). Which boils down to electrically isolated digital i/o with power supply referenced conversion.
Old 4 weeks ago
  #14
Gear Addict
 
audiospecific's Avatar
 

Quote:
Originally Posted by Dan O View Post
Too bad. Thunderbolt seems quite good otherwise.
Well I'm not trying to scare you away from the Orion, but I wouldn't connect it the same way they would.

I would use a isolated or battery powered laptop, and use the usb for control, then route the I/O for recording side through the madi or the ADAT. The only side issues I would see is possible ground loops that might form on the analog input side. But like I said before I would have to investigate the input grounding scheme to see if they break any possible ground loops internally.
Old 4 weeks ago
  #15
Gear Maniac
 
Dan O's Avatar
 

Quote:
Originally Posted by audiospecific View Post
Well I'm not trying to scare you away from the Orion, but I wouldn't connect it the same way they would.

I would use a isolated or battery powered laptop, and use the usb for control, then route the I/O for recording side through the madi or the ADAT. The only side issues I would see is possible ground loops that might form on the analog input side. But like I said before I would have to investigate the input grounding scheme to see if they break any possible ground loops internally.
Ok, thanks for the info, very interesting.

Well I've already aquired a brand new mac mini and was set on getting a thunderbolt interface since it seems pretty stable with very low latency on 32 channels, which i need.

I guess I've been sort of ignoring this grounding issue with the DAW. I also have a lot of analog equipment, outboard, tape machines and so on. All equipment has has been star grounded including all electrical outlets to my console star point.

Just when I wrote this I realized that the mac mini has only got a two pin connector without safety ground. The same goes with all the stuff connected to the mini except for the Orion interface. I guess it doesn't solve the issue with eventuel PSU noise but might not be a groundloop problem then?
Old 4 weeks ago
  #16
Gear Addict
 
audiospecific's Avatar
 

Quote:
Originally Posted by Dan O View Post
Ok, thanks for the info, very interesting.

Just when I wrote this I realized that the mac mini has only got a two pin connector without safety ground. The same goes with all the stuff connected to the mini except for the Orion interface. I guess it doesn't solve the issue with eventuel PSU noise but might not be a groundloop problem then?
Well the NUC style pc boards including mac mini usually are powered by an isolated switching power supply. They are only noise prone when the power supply is pushed. Like too many things USB powered plugged in. It shouldn't be an issue however, I've seen usb powered mechanical hard drives cause noise on the usb.
Old 4 weeks ago
  #17
Gear Maniac
 
Dan O's Avatar
 

Quote:
Originally Posted by audiospecific View Post
Well the NUC style pc boards including mac mini usually are powered by an isolated switching power supply. They are only noise prone when the power supply is pushed. Like too many things USB powered plugged in. It shouldn't be an issue however, I've seen usb powered mechanical hard drives cause noise on the usb.
Well OK, sounds like there's hope for the mac mini then.


This is what I intended to connect.

-One or two monitors. One 43" LED TV ( no GND) and one apple computermonitor (Might have a safety ground, must check that).

- One Faderport controller powered both through USB and powersupply. I think the PSU is for the motorized fader.

- One external drive. USB or Firewire to Thunderbolt with its own PSU.

- Keyboard and mouse with bluetooth. ( This is another topic but do you know if bluetooth can have any interference on my analog console or other equipment in the studio? )

- One RJ45 from router for internet. Might be a problem here!? Otherwise maybe i can use wifi.
Old 4 weeks ago
  #18
Gear Addict
 
audiospecific's Avatar
 

Quote:
Originally Posted by Dan O View Post
Well OK, sounds like there's hope for the mac mini then.


This is what I intended to connect.

-One or two monitors. One 43" LED TV ( no GND) and one apple computermonitor (Might have a safety ground, must check that).

- One Faderport controller powered both through USB and powersupply. I think the PSU is for the motorized fader.

- One external drive. USB or Firewire to Thunderbolt with its own PSU.

- Keyboard and mouse with bluetooth. ( This is another topic but do you know if bluetooth can have any interference on my analog console or other equipment in the studio? )

- One RJ45 from router for internet. Might be a problem here!? Otherwise maybe i can use wifi.
I don't think you should have any real issues. as far as the Ethernet vs WIFI I would go Ethernet and disable the wifi because the wifi firmware driver might fight for real time processing. Granted, these drivers are not as bad as the ones used in the windows operating systems. Rj45 Ethernet is balanced twisted pair digital communications.
Old 4 weeks ago
  #19
Gear Maniac
 
Dan O's Avatar
 

Quote:
Originally Posted by audiospecific View Post
I don't think you should have any real issues. as far as the Ethernet vs WIFI I would go Ethernet and disable the wifi because the wifi firmware driver might fight for real time processing. Granted, these drivers are not as bad as the ones used in the windows operating systems. Rj45 Ethernet is balanced twisted pair digital communications.
Ok, cool, thanks!
Topic:
Post Reply

Welcome to the Gearslutz Pro Audio Community!

Registration benefits include:
  • The ability to reply to and create new discussions
  • Access to members-only giveaways & competitions
  • Interact with VIP industry experts in our guest Q&As
  • Access to members-only sub forum discussions
  • Access to members-only Chat Room
  • Get INSTANT ACCESS to the world's best private pro audio Classifieds for only USD $20/year
  • Promote your eBay auctions and Reverb.com listings for free
  • Remove this message!
You need an account to post a reply. Create a username and password below and an account will be created and your post entered.


 
 
Slide to join now Processing…
Thread Tools
Search this Thread
Search this Thread:

Advanced Search
Forum Jump
Forum Jump