• Registered: 2022-02-19
  • Posts: 3

Topic: Ray DAT SPDIF ground loop problem

Hi everyone,

I have solved a ground loop problem by utilising a Palmer active DI box.

Signal path RayDAT AES out into a Loudspeaker Management System into the DI Box and then into the speakers.

I would like to use the RAY DAT SPDIF digital out  into a drawmer CMC3 Monitor Controller. If I do so, I am plagued by a rather loud hum.


Could you guys please point me in the direction of a capable solution for my problem that does not degrade Sound Quality.

Can DI boxes for SPDIF be used for either analog or digital connections?

Many thanks,

R4Y

2 Reply by MC

  • MC
  • MC
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  • Registered: 2007-04-06
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Re: Ray DAT SPDIF ground loop problem

SPDIF is not directly tied to the ground of the computer. Are you sure the noise starts just by connecting the SPDIF connector outer shell with the SPDIF input of that Drawmer? Or is the problem already there without SPDIF connection?

Regards
Matthias Carstens
RME

MC's Website

  • Registered: 2022-02-19
  • Posts: 3

Re: Ray DAT SPDIF ground loop problem

Hi Matthias,

Thank you for answering. Unfortunately, I am certain. As soon as the connection to the spdif In on the drawmer is established, the trouble starts.

4 Reply by MC

  • MC
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Re: Ray DAT SPDIF ground loop problem

I have to take that back: the RayDAT's SPDIF output is indeed connected to ground of the computer. You seem unlucky as the Drawmer also does't provide galvanically isolated inputs. A solution would be this device, which galvanically isolates both sides:

https://www.epanorama.net/blog/2009/10/ … isolation/

Unfortunately I did not find this stuff pre-build with a simple RCA I/O and for reasonable prices.

Neutrik has such transformer based isolators, even the price is ok, but there you need additional adapters to change from BNC to RCA and from XLR to RCA...

Regards
Matthias Carstens
RME

MC's Website

  • Registered: 2022-02-19
  • Posts: 3

Re: Ray DAT SPDIF ground loop problem

Thank you,

Even without an immediate solution this helped a lot. The drawmer is quite a let down when it comes to the inputs. It is otherwise a device that has everything I need (although the buttons are made of plastic and I had to replace two of them in three years)

Regarding the fact that I needed the DI Box in conjunction with the drawmer for AES as well, I could have spent more money on a monitor controller in the first place that provides galavinzed inputs.

One way or the other,

Lesson learned.


Thanks again Matthias

  • vinark
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  • Registered: 2009-06-05
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Re: Ray DAT SPDIF ground loop problem

@MC
Is there a chance that simply disconnecting ground of the spdif cable might work?
Might be worth a try anyway

Vincent, Amsterdam
https://soundcloud.com/thesecretworld
Babyface pro fs, HDSP9652+ADI-8AE, HDSP9632

7 Reply by MC

  • MC
  • MC
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Re: Ray DAT SPDIF ground loop problem

If one can remove the ground connection one could also add a small capacitor (100 nF) between the grounds, and the ground loop would be gone with SPDIF fully working...it's always a matter of how much DIY one can do...

Regards
Matthias Carstens
RME

MC's Website