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Please help me understand SPDIF and DAC's!

MysteryMan

Established Member
I am hoping you good folk can help me understand the possibilities and limitations available to me.

I have:
  • 2-channel amp/speaker set up
  • Media player (Med8er) that has Digital Audio output, which can be set to "SPDIF Downmix (2 channel)"
  • DAC
I use the media player to play .ISO images of DVD's (music videos) and was hoping to use the DAC to improve the sound quality of these.

However, when connected, I get no sound out of system!

Can someone tell me if this should work or whether I am wasting my time?

If this wont work, are there any DVD players that would do what I want?
 

Don Dadda

Distinguished Member
What dac and dvd player do you have and how is it connected?

There is a sticky above if you wish to have a better understanding of dacs and their usage.
 
Last edited:

MysteryMan

Established Member
What dac and dvd player do you have and how is it connected?

There is a sticky above if you wish to have a better understanding of dacs and their usage.

Yeah, read the sticky and although it is very helpful, it doesn't really address my issue.

I do not have a DVD player - I have a Med8er media player!

I have an Oppo 983 I could try.

The DAC is not a commercial offering - the details can be found in the second half of this post.....

Monster DAC
 

Don Dadda

Distinguished Member
Oops sorry about that, i misread the your post about the iso images.

Sorry for the stupid question but the dac is on the correct selection for Med8er and the amp likewise?

I don't know anything about that particular dac so i may not be much help to you, (hopefully someone else does and is), but If connected between the Med8er and the amp, it should work. It is possible that the dac or cable to the amp could be faulty unless you have proved otherwise. I am assuming you are taking the digital out from the Med8er to the dac's optical input dac and the dac's XLR analogue outputs to the amp.

The link below is the rear view of the Behringer Ultramatch PRO SRC2496, is this what you have?
Behringer Ultramatch PRO SRC2496 rear view
 

MysteryMan

Established Member
Oops sorry about that, i misread the your post about the iso images.

Sorry for the stupid question but the dac is on the correct selection for Med8er and the amp likewise?

I don't know anything about that particular dac so i may not be much help to you, (hopefully someone else does and is), but If connected between the Med8er and the amp, it should work. It is possible that the dac or cable to the amp could be faulty unless you have proved otherwise. I am assuming you are taking the digital out from the Med8er to the dac's optical input dac and the dac's XLR analogue outputs to the amp.

The link below is the rear view of the Behringer Ultramatch PRO SRC2496, is this what you have?
Behringer Ultramatch PRO SRC2496 rear view

Yes, this is the unit that DAC is based on, although it is just using the PCB from it to upsample. The rest of DAC is custom built in its own box!

Yes, connections are OK. My concern is the different digital signals involved. I don't really understand what they are and whether they are compatible between Med8er and DAC! :lease:
 

Don Dadda

Distinguished Member
Have a read of the link below, i'm hoping that it will shed some light on digital signals for you.

Dolby Digital - Wikipedia, the free encyclopedia

I know some or most dacs cannot handle DTS as you may of read in the sticky but unsure of others. Besides that and truehd, i believe the rest are convertable. Hopefully someone can confirm whether this is true or not as i cannot find any info on the web to suggest either way.

Sorry i couldn't be more helpful
 

Mark.Yudkin

Distinguished Member
I know you have a med8er. DVD players have the option to issue 2 channel PCM, and to limit the data rate to 48kHz. This format works with most stereo DACs on the market (I know yours isn't). although there are stereo DACs that understand formats such as Dolby Digital, support is by no means ubiquitous. The option "SPDIF Downmix (2 channel)" sounds like it ought to be correct, but since it doesn't work you should recheck the manual to ensure it means PCM, and limit the rate to 48kHz.

S/PDIF is a data link protocol, not a content definition - it says nothing about the content of the signal it transfers. You need to select a format supported by both ends.
 

MysteryMan

Established Member
I know you have a med8er. DVD players have the option to issue 2 channel PCM, and to limit the data rate to 48kHz. This format works with most stereo DACs on the market (I know yours isn't). although there are stereo DACs that understand formats such as Dolby Digital, support is by no means ubiquitous. The option "SPDIF Downmix (2 channel)" sounds like it ought to be correct, but since it doesn't work you should recheck the manual to ensure it means PCM, and limit the rate to 48kHz.

S/PDIF is a data link protocol, not a content definition - it says nothing about the content of the signal it transfers. You need to select a format supported by both ends.

Thanks! I will try to find out what the "SPDIF Downmix (2 channel)" option outputs.

Sounds like I should try a DVD player and use 2-channel PCM and 48kHz.

Cheers!
 

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