1212m ans spdif

[krautxy]

Hello,
i am from germany and there is not much information available about 1212 m .
Question: if i am using 1212 spdif with an external DAC are there important settings in 1212 software and foobar for sound quality.
I want to use it beside an high quality satandalone solution.

Thanks
Alfred

 

[audioengr]

I'm not aware of any problems with the software, however the S/PDIF output circuitry can perform much better with mods. It is truly a reference digital out once modded.

 

[Glassman]

could you, please, elaborate a bit?

 

[rayofsi]

Quote:

Originally Posted by audioengr The problem with the 1212 is not the software, it's the hardware. The S/PDIF output circuitry does not meet spec and needs to be modded to perform well.

yes how would i correct it? i know that the output levels are 3 times over s/pdif spec.

 

[gaboo]

Quote:

Originally Posted by audioengr The problem with the 1212 is not the software, it's the hardware. The S/PDIF output circuitry does not meet spec and needs to be modded to perform well.

I hope you solid proof for your claims. I see Creative's army of lawyers coming your way...

They (Creative) have put out of business companies that did nothing wrong (Aureal), so even if you're right, pray they don't hear you...

<Ducking under a pile of Vortex2 chips>

 

[gaboo]

This is what ICHi has to say about it: http://www.productionforums.com/emu/...?TOPIC_ID=1044

 

[audioengr]

Quote:

Originally Posted by gaboo I hope you solid proof for your claims. I see Creative's army of lawyers coming your way... They (Creative) have put out of business companies that did nothing wrong (Aureal), so even if you're right, pray they don't hear you... <Ducking under a pile of Vortex2 chips>

The word "problem" is a bit harsh, so I edited my test. There are no problems with the hardware. The 1212 works fine. The S/PDIF spec says 400-600 mV peak-to-peak. The output is actually much higher than this, however it is not of particular consequence. Most DAC's can handle it.

The bigger issue is one that all transports have as well, and that is the emissions issue. In order to pass emissions testing, the manufacturer is forced to test the device with a low-quality cable attached. To pass FCC, CISPR, and CSE regulations, the manufacturer typically puts filtering in and slows the edge-rates to reduce emissions. They have no choice really. The problem with this is that when the customer uses a good quality S/PDIF cable, the slow risetimes contribute to jitter. Modding it can speed-up the edge rates and more precisely match the impedance, reducing jitter. This also allows the use of shorter cable lengths. 1.5m is required for most stock transports to minimize jitter, but the stock 1212 will probably work fine with 1m length because it's risetime is faster than the typical transport. Read this article for more info:

S/PDIF cable length

 

[gaboo]

Quote:

Originally Posted by audioengr The S/PDIF spec says 400-600 mV peak-to-peak. The output is much higher than this. It is not of particular consequence however. Most DAC's can handle it.

I suspect 1010 (the pci card) puts out AES/EBU voltages even in S/PDIF mode. Right? It's a cheap card after all, so you'd expect some corners to be cut, but hey, if it works...

Quote:

Originally Posted by audioengr The bigger problem is the one that all transports have as well, and that is the emissions issue. In order to pass emissions testing, the manufacturer is forced to test the device with a low-quality cable attached. To pass FCC, CISPR, and CSE regulations, the manufacturer typically puts filtering in and slows the edge-rates to reduce emissions. They have no choice really. The problem with this is that when the customer uses a good quality S/PDIF cable, the slow risetimes contribute to jitter. Modding it can speed-up the edge rates and more precisely match the impedance, reducing jitter. This also allows the use of shorter cable lengths. 1.5m is required for most stock components. Read this article for more info: S/PDIF cable length

For a card like 1212m is more economical to buy the wordclock daughter card ($79), and use the DAC as the clock source. A DAC that's jitter sensitive should come with output word clock, or else is not worth buying. Buying expensive cables, and modding the card to feed some crappy DAC doesn't seem warranted. Now you'd have to buy an expensive cable for the clock.

Btw, for audio playback of recordings S/PDIF makes no sense whatsoever. All that clock/jitter problem caused by transmitting data at the playback rate makes no sense. Burst isochronous mode like USB Audio or IEC-61883-6 (the firewire equivalent) is the way to go IMO. I applaud your modding of dacs/receivers with USB ports. Maybe manufacturers will get clue.

If anybody doubts the above statement, take look at your CD/DVD recorder. As long as the buffer stays full, the laser has no problem whatsoever writing the disc. The laser is a DAC, a very special one.