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[MikeO]

Hi

A simple question if you know the answer...

The Audiolab M-DAC has a Coax and an Optical output . My understanding is that when fed from USB , these 2 outputs allow the output of a "raw unprocessed " or at least minimally processed digital signal that then be decoded by any AV amp to produce 5.1 audio.

Maybe my ears ain't what they used to be but I often wonder if this route is giving me 5.1 on files that I know contain 5.1.

Has anyone come across this DAC , Audiolab seem a bit slow with their support calls hence I ask here

Cheers

Mike

[BryanC]

I don't know about the capabilities of your specific hardware but s/pdif is only capable of transferring 2-channel PCM. That hardware might be able to pass-through compressed DTS or DD audio but that's a big IF. If you are using an external A/V receiver with HDMI inputs, the best option is to forget about the M-DAC and use HDMI from your computer directly to your receiver.

[ken-tajalli]

Very much doubt it, since the USB, Coax and optical inputs only support 2 channel audio.
If it is not going in, it can not come out!
I believe your AV amp is transcoding two channel audio into pseudo 5.1 channel output.
It's a trick, and some do very good jobs indeed.

[Micromecca]

As already stated the M-DAC can only accept 2CH PCM.
Your best bet at Audiolab is Steve Hughes via telephone for any support questions however, youre likely to get a more in-depth response from John Westlake (the designer of the M-DAC). He usually responds really quickly over at PFM on the dedicated M-DAC Thread

M

I don't know about the capabilities of your specific hardware but s/pdif is only capable of transferring 2-channel PCM. That hardware might be able to pass-through compressed DTS or DD audio but that's a big IF.

The M-DAC will mute and display 'Encoded Bitstream' in this situation

EDIT: I should of added that the above applies to the USB Input and the M-DAC can pass multi channel PCM and Bitstream on the SPDIF In/Outs.

[MikeO]

Hi All

Got a definitive reply from John W, its a combination of the above

The USB input only handles 2 channels , hence 2 In 2 Out -- foolish to expect anything else
However If you use a Coax or Optical 5.1 source in then the Optical/coax OUTPUT sends that 5.1 out

So I was on the right track , but missed the USB 2 channel input. The other problem is my AV amp is a bit aged and does not have HMDI input/output only Coax & Optical

The answer is to have a PC with an optical output that passes 5.1 direct to the amp

Or to have a AV Amp with HDMI in/out so that the sound is passed through the HDMI to the amp and the picture from the amp to the TV (Probably the better route as it will enable Dolby HD I assume)

Bottom line is new hardware either way, I have had to resurrect the Mede8er 1x10003D and run a separate stream for audio (JRiver -> DAC) and video (Mede8er) until I renew hardware.

Mike