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#281662 - 2019-01-12 12:14 Re: Ultra DAC with external streamer [Re: Carl]
Registered: 2002-02-14
Posts: 8,499
ncpl Offline
President of the Imperial Galactic Government
ncpl Offline

President of the Imperial Galactic Government

Registered: 2002-02-14
Posts: 8,499
Loc: Surrey, UK
Originally Posted By Carl
Agreed, I should have said Meridian’s ID41 architecture.
IIRC when I asked HQ about the USB input and 192k, the answer was that it would still be down converted to 96k inside the 8xx unit. The limit on the architecture is not just the ID41.

There was the inference, however, in one of HQ's last posts on the general topic of Sooloos future (in the light of the Roon departure) that a future enhancement would allow for handling of higher res content. In my dreams I read that to mean the encapsulation of >96k material into an MHR/MQA-variant that could then be unpacked at the suitable MQA end-points. Thus by-passing the 96k pipe limit. I recall a conversation at one of the London meetings in Chelsea skirting around this topic too.

Now, if an encapsulation .exe could be implemented into the Sooloos engine (highly unlikely) or the Roon DSP engine (more likely than Sooloos but still a long shot) then it would have mass appeal to practically every M user new, old and future.

Just my 2p


Rgds,
Nick

#15SE
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#281673 - 2019-01-12 16:57 Re: Ultra DAC with external streamer [Re: ncpl]
Registered: 2008-05-23
Posts: 7,892
Carl Offline
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Carl Offline


President of the Imperial Galactic Government

Registered: 2008-05-23
Posts: 7,892
Loc: Central England, UK
Hi Nick,

I was pretty confident the > 96KHz is an architectural limitation of the 808, 818, 861 units but I’m not sure that applies to the UltraDAC, hence I hedged my bets and agreed with ID4x comment.

What are your thoughts on the UltraDAC’s capabilities in supporting > 96KHz input from USB and SPDIF?

Regards
Carl


861v6+ID40, HD621, 8000.2, 7200HC, 7200.2, SKYQ Silver, PS3, PDP-LX6090, QNAP TS870-Pro (8*6TB), Roon, iPadAir2.
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#281709 - 2019-01-13 23:09 Re: Ultra DAC with external streamer [Re: ncpl]
Registered: 2018-12-31
Posts: 14
AudioIdiot Offline
Harmless
AudioIdiot Offline
Harmless

Registered: 2018-12-31
Posts: 14
Loc: Tilburg, The Netrherlands
The specification says the each channel runs on 4 hierarchical configured 192kHz DACs.
To me it would be strange to downsample to 96kHz.

Yes the 384kHz sources are down sampled to 192 on USB.
So I guess that this means a deviation from the 8xx series, that I don't know.

A friend has an ALLO usbridge, and that is recognised by Roon, so I can test that soon.
This unit will allow 192kHz so I can compare Roon down sampled to 96 and direct to USB.
But that ALLO is not the most sophisticated units wrt clock integrity.

I'll report the results in the next two weeks or so
Peter


Ultra DAC
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#281724 - 2019-01-14 08:42 Re: Ultra DAC with external streamer [Re: Carl]
Registered: 2002-02-14
Posts: 8,499
ncpl Offline
President of the Imperial Galactic Government
ncpl Offline

President of the Imperial Galactic Government

Registered: 2002-02-14
Posts: 8,499
Loc: Surrey, UK
Good question @Carl. I make a the assumption that the UltraDAC shares much DNA with the other 8xx units

1) because I haven’t heard that HQ has created a new architecture in any promo materials or data sheets
2) it is usually expensive to start a new of architecture so I would expect HQ not to do that unless it was going to maximise that with changing other lines over to it (shared materials spread the costs etc). I can’t see that happening.

So, until I can find a reason to think otherwise I’ll stick with my assumption.

Happy to see if I need to revise that though.


Rgds,
Nick

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#281726 - 2019-01-14 09:24 Re: Ultra DAC with external streamer [Re: ncpl]
Registered: 2004-04-15
Posts: 12,505
VirusKiller Offline
Don't Panic
VirusKiller Offline
Don't Panic

Registered: 2004-04-15
Posts: 12,505
Loc: nr. Milton Keynes, UK
I don't know what is happening in the Ultra DAC. However, I think that it probably shifts audio around at 96k.

According to Bob, there is no *music* content above 48k, only (important) information about the noise floor.

It would seem surprising if >96k was just down-sampled to 88 or 96k, but perhaps with non-MQA material (which doesn't have the benefit of non-real-time audio analysis), that's all that can be done? I'm not totally convinced though.

<speculation>
It's possible that >96k and DSD128 inputs are converted to 88 or 96, maintaining the noise floor info (for rendering) in an MQA-like side chain.
</speculation>.

The data sheet info stating 192k DACs seems wrong to me, but then again, no one really has a clue as to what "hierarchically configured DACs" means.


Roon Developer and ex-moderator of this Forum
I am #25 in the HH1 photo of fame.
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#281732 - 2019-01-14 12:16 Re: Ultra DAC with external streamer [Re: VirusKiller]
Registered: 2002-02-14
Posts: 8,499
ncpl Offline
President of the Imperial Galactic Government
ncpl Offline

President of the Imperial Galactic Government

Registered: 2002-02-14
Posts: 8,499
Loc: Surrey, UK
Your speculation is also what I was getting at with an MQA type encapsulation. Probably feasible to do it on a one box DAC. Less clear if it could be done into say DSP SE.


Rgds,
Nick

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#281768 - 2019-01-14 23:56 Re: Ultra DAC with external streamer [Re: VirusKiller]
Registered: 2018-12-31
Posts: 14
AudioIdiot Offline
Harmless
AudioIdiot Offline
Harmless

Registered: 2018-12-31
Posts: 14
Loc: Tilburg, The Netrherlands
The Ultra DAC is running on 192k. I just remembered why.

Read the test of this DAC in Stereophile. John Atkinson does a full set of measurements and shows a -3dB response at 80kHz analog bandwidth with a 192kHz signal,
This is not possible if the unit would down sample to 96k. It shows a 35kHz analog bandwidth with a 96k sampled test signal.

In theory the analog bandwidth of a DAC is maximum 1/2 the sample frequency. The smooth filter of the Ultra DAC shows a bit less than the theoretical max.

I read somewhere that the hierarchical DAC is a method of using multiple DACs in parallel but with a sub sample offset between them.

Paralleling DACs lowers the noise, every doubling lowers the noise by 3dB, so 6dB for the four DACs in the Ultra. What the hierarchical method brings is not completely clear but it must randomise the nonlinearities to a more analog behaviour I think.

Peter




Ultra DAC
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