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MDAC First Listen (part 00011110)

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Dodeth said:
Thanks John. Does it need to be powered? (apologies if this is a daft question - I confess I know nothing about USB hubs!)
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Hi Dodeth,

no need for power.
I haven't tried MDAC using anything else than USB, for me Asynch USB is just "right" :)
 
Hi, I'm using the MDAC with a Bluesound Node via optical. When I play 24 bit FLACS the display always shows 16bit. I'm using firmware vA.10.
Bluesound support tells me the node cannot downsample so outputs the files at 24 bit. Do you have an idea? The samplerate does show correctly btw. Thanks!
 
John_Bass said:
Hi, I'm using the MDAC with a Bluesound Node via optical. When I play 24 bit FLACS the display always shows 16bit. I'm using firmware vA.10.
Bluesound support tells me the node cannot downsample so outputs the files at 24 bit. Do you have an idea? The samplerate does show correctly btw. Thanks!
Click to expand...

Bottom 8 bits have been padded with zeros and contain no data
 
JohnW said:
To use the MDAC with SBT via the USB you need a USB2.0 hub to act as a "USB packet" reformatter'.
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The EDO version I have has a "No hub workaround" (I have also set the SBT to Large Buffer setting). Does anyone know if adding a hub would still be better?

Cheers,
Kevin.
 
John_Bass said:
Interesting...can you explain more? Is it file related? thx! :)
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There are some previous posts in these mega threads...

IIRC the mdac looks at the actual data passing through it and reports on the number of bits that are actually changing.

I believe there are some utilities that will let you see the actual values in the flac files.

I think you'll find that if the mdac is reporting 16 bits then only the top 16 bits are changing and the bottom 8 bits are 'stuck' - not changing. Hence it's actually a 16 bit file
 
JohnW said:
Hi Pavel,
Yes - we are still some way from having the first boards ready - but as your quite local to us (just south of Brno) we can arrange to meet and have your unit upgraded with the prototype Analogue stage once its ready - it would be good to have feedback from a headphone users.
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John,
Thank you for your offer.
Pavel.
 
Steven Toy said:
It would seem that there are two MDAC2 camps emerging: the hair shirt types like me who just want the best uncompromised sound quality and the fully-feature-laden bells-and-whistles set.

I hope both can be accommodated without the former having to pay for things that they don't want but the latter do.
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I am already getting things I don't want like the AV pass trough. Prefer to keep stereo and AV system completely separate. The MDAC2 will never get connected to my AV receiver.

But I do find the DSP option a nice extra bonus worth paying for even if it should turns out that room correction does not improve the SQ in my room. Then £100 is still a cheap way of trying it.

So there will be no complaints from me only if multi channel and inbuilt streaming keeps being requested.
 
+1 for DSP& blutooth.
DSP is very interesting since it gives some future proofing, I guess John and Dominik will think of neat stuff to use it for in the future?
Just the option to play with some simple room correction and possible some crossfeed options will for me be worth the extra 100£.
 
Rune said:
I am already getting things I don't want like the AV pass trough. Prefer to keep stereo and AV system completely separate. The MDAC2 will never get connected to my AV receiver.
Click to expand...

Its worth noting that while we have called the external analogue input "AV Bypass" it can also be used to connect an external analogue input, say from a Phone stage - which might have more relevance to a Pure HiFi system.
 
John_Bass said:
Interesting...can you explain more? Is it file related? thx! :)
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John,

Chris has already replied correctly (thank you Chris) - The MDAC analyses the input data and confirms which bits are changing, so if only the first 16bits are toggling (such as in your case) then it reports the data as 16bits - basically the last 8bits of the 24 word are not changing thus the data input only contains 16 bits of "audio" information.

Its surprising (or some would say not) how many times its caught out files being sold as 24bits - while they are in fact standard 16 Bit CD files.

Where did you get your "24 bit FLACS" its very possible that the original file before before being encoded in FLAC was a 16 Bit Audio file from say a CD.
 
Thank you Chris and John for the explanation!

The files are 24bits, as a matter of test i've put the same flacs a on stick and played them via my Marantz UD7007 (coax) and Western Digital WD TV Live (optical, same cable) through the MDAC, then it displays 24bit. Just playing them through the BSS Node shows up as 16bit. The BSS app recognizes and displays the files as 24bit and from BSS support I learned that the Node is not able to downsample... :confused: Unless the Marantz and WD process the 8 '0'bits differently than the Node...
 
Beware the terminology being used.

'....sample' ie. downsample (or more usually 'upsample') usually refer to a change in sampling frequency and not the number of bits. The results you are describing here sound like 'truncation' ie the last 8 bits are being chopped off
 
Good point! But with 8 bits being chopped off should that not corrupt to influence the output? There should be missing info I guess. The files plays fine and the sound quality is great.

(Sorry for my questions but I have not so in-depth technical knowledge of the matter but are very interested :) )
 
John,

It would appear that the BSS Node either has a software bug or the hardware despite what's claimed cannot support 24 bit data - have you ever seen 24 bits displayed via the BSS Node / MDAC?

I suspect BSS are unaware of the problem and have just assumed the 24bit mode functions correctly - As far as I know, the MDAC's maybe the only product commonly available that clearly indicates the true bit depth.
 
JohnW said:
Its worth noting that while we have called the external analogue input "AV Bypass" it can also be used to connect an external analogue input, say from a Phone stage - which might have more relevance to a Pure HiFi system.
Click to expand...

Thanks John for pointing that out. Now it suddenly sounds like a useful feature after all :)
 
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