1 Topic by cowudders (edited by cowudders 2023-02-18 21:25:40)

  • Registered: 2007-07-31
  • Posts: 99

Topic: Digiface USB - noise on headphone outs

I'm strongly thinking about changing from my still totally fine Mac Pro 5,1 with a RayDAT to a new MacMini M2 pro with the Digiface.
Ordered and got one, will miss the TCO options and the additional AES & Spdif I/O, but it makes more sense to buy this than going a PCIe enclosure route (which costs more than the digiface) for the RayDAT.

My question:  I wanted to use the Digiface on my macbookpro 2014 on a live gig and use the headphone-outs to the PA, but got lots of 'usb noise bleed' when the charger was connected. is this normal behaviour? i somehow don't expect this from a RME product, but maybe i don't get something here or have a faulty Digiface?

thanks!

DigifaceUSB/BabyfacePRO/MacMini M2Pro 12-core 32GB/Sonoma 14.7/Logic/Reaper
  • waedi
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Re: Digiface USB - noise on headphone outs

It is connected directly to the computer, without any hub, right ?
My MacbookAir is connected to the charger and the headphone output of the Digiface USB sounds clean and perfect.
There could be a problem with the USB cable ?

M1-Sequoia, Madiface Pro, Digiface USB, Babyface silver and blue
  • Registered: 2007-07-31
  • Posts: 99

Re: Digiface USB - noise on headphone outs

hi,
yeah, the typical usb-garbage-noise is only there when connected to a mixer, interface via an obviously unbalanced TRS->2xTS cable. on headphones there's no noise at all. will try a different cable.

DigifaceUSB/BabyfacePRO/MacMini M2Pro 12-core 32GB/Sonoma 14.7/Logic/Reaper

4 Reply by MC

  • MC
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  • Registered: 2007-04-06
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Re: Digiface USB - noise on headphone outs

The MacMini M2 uses a switched mode, ungrounded power supply. As usual giving the unit ground directly will prevent the leakage current to flow other ways to a different, grounded unit.

This has nothing to do with the Digiface USB.

Regards
Matthias Carstens
RME

MC's Website

  • Registered: 2007-07-31
  • Posts: 99

Re: Digiface USB - noise on headphone outs

MC wrote:

The MacMini M2 uses a switched mode, ungrounded power supply. As usual giving the unit ground directly will prevent the leakage current to flow other ways to a different, grounded unit.

This has nothing to do with the Digiface USB.

I've had this happening wih my Macbook Pro from 2014 - so a transformer/DI box should help?

DigifaceUSB/BabyfacePRO/MacMini M2Pro 12-core 32GB/Sonoma 14.7/Logic/Reaper

6 Reply by MC

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Re: Digiface USB - noise on headphone outs

It would, but affect the audio quality. Cheapest solution - the proposed grounding. Expensive solution - USB isolator.

Regards
Matthias Carstens
RME

MC's Website

  • Registered: 2007-07-31
  • Posts: 99

Re: Digiface USB - noise on headphone outs

MC wrote:

It would, but affect the audio quality. Cheapest solution - the proposed grounding. Expensive solution - USB isolator.

yeah, for live not really a big problem - thanks.
and thanks for all the great hard- and software you're making, matthias!

DigifaceUSB/BabyfacePRO/MacMini M2Pro 12-core 32GB/Sonoma 14.7/Logic/Reaper
  • Registered: 2007-07-31
  • Posts: 99

Re: Digiface USB - noise on headphone outs

MC wrote:

The MacMini M2 uses a switched mode, ungrounded power supply. As usual giving the unit ground directly will prevent the leakage current to flow other ways to a different, grounded unit.

This has nothing to do with the Digiface USB.

now i get that, may i ask how do i ground a macbook, how do i ground a mac mini? attach a groundwire to the chassis? smile no really i have no idea ...

DigifaceUSB/BabyfacePRO/MacMini M2Pro 12-core 32GB/Sonoma 14.7/Logic/Reaper

9 Reply by MC

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Re: Digiface USB - noise on headphone outs

I overlooked the target 'PA'. In that case any sound degradation by analog DI isolator devices can be ignored.

For grounding the MacBook: use any connector available that has ground contact. Shield of USB etc...most easy would be ground of headphone out, if that one (still) exists...

Regards
Matthias Carstens
RME

MC's Website

  • Registered: 2007-07-31
  • Posts: 99

Re: Digiface USB - noise on headphone outs

MC wrote:

For grounding the MacBook: use any connector available that has ground contact. Shield of USB etc...most easy would be ground of headphone out, if that one (still) exists...

ahh, thanks, gonna try this!

DigifaceUSB/BabyfacePRO/MacMini M2Pro 12-core 32GB/Sonoma 14.7/Logic/Reaper