[Icy006]

My apologies if this has been posted before, I couldn't find it.

http://www.dvdupgrades.ch/150019/Mod...put_board.html

Being a CompE, I bow down to this feat - these fellows managed to make an add-on for just about any high-res player that taps the internal digital bitstream and will yield 3 stereo S/PDIF outputs from DVD, CD, DVDa, SACD, etc. It gives you "6-channel electrical S/P-DIF output PCM 16-24 Bits 44.1/48/88.2/96/176.4/192 kHz".

The really impressive part is that this thing converts SACD's DSD bitstream to PCM to chuck it over to the S/PDIFs. That's "SACD: DSD 1 Bit 2.8224 MHz switchable conversion to PCM 24 Bits 88.2 kHz or 176.4 kHz".

I don't suppose anyone here actually pulled the trigger and forked out the coin for this?

 

[myhui]

Quote:

Originally Posted by Icy006 ... taps the internal digital bitstream and will yield 3 stereo S/PDIF outputs from DVD, CD, DVDa, SACD, etc.

Here is how you can do it.

A Cirrus Logic CS4397 DAC has 1-bit DSD inputs, unencrypted. A lot of SACD players on the market use that DAC.

They also sell an evaluation board for that DAC. I have been listening to one at home for years, but in PCM mode only.

So ...

Pick off the DSD stream from the commercial SACD player, both clock and data, and send a short burst of it into a computer when a SACD with just a test tone is playing. Then use your knowledge of delta-sigma modulators to process it in software, to turn it from DSD into PCM. Once you get it right, design a logic circuit that can do the same thing in an FPGA. Then sell the FPGA on a board, with DSD inputs at one end, S/PDIF outputs at the other end.

The reason you need the eval board is that it gives you a lot of information about the timing of the signals, and the datasheet for the DAC that's on the board gives a lot of information about the filter characteristics inside the DAC when it is operating in DSD mode. Having the same DAC in the commercial SACD player as on the eval board is crucial, obviously.

A variation on this method is how you can, one day, with a lot of effort, convert a PCM-only, flash memory-based music player into a SACD capable one. The capture to computer part is all you need for this project, since you can simply replace the DAC in the player with a DSD-capable DAC, and have the music player's CPU send DSD output to the DAC instead of PCM, with a corresponding bit rate adjustment.

 

[Ferbose]

This sounds cool.
For SACD and DVD-A to survive as an audiophile media, I think digital out is crucial. When will those two camps realize that?

 

[Oliver :)]

Sick mod... costs more than my 2900 when new. I guess if you actually do have active digital speakers in a multichannel setup this might be well worth it.

 

[Mikey01]

Quote:

Originally Posted by Icy006 My apologies if this has been posted before, I couldn't find it. http://www.dvdupgrades.ch/150019/Mod...put_board.html Being a CompE, I bow down to this feat - these fellows managed to make an add-on for just about any high-res player that taps the internal digital bitstream and will yield 3 stereo S/PDIF outputs from DVD, CD, DVDa, SACD, etc. It gives you "6-channel electrical S/P-DIF output PCM 16-24 Bits 44.1/48/88.2/96/176.4/192 kHz". The really impressive part is that this thing converts SACD's DSD bitstream to PCM to chuck it over to the S/PDIFs. That's "SACD: DSD 1 Bit 2.8224 MHz switchable conversion to PCM 24 Bits 88.2 kHz or 176.4 kHz". I don't suppose anyone here actually pulled the trigger and forked out the coin for this?

Sorry! I am getting lost in the techno talk here. (slow learner) So, it may be possible to put this puppy in the Eastsound E5 (a redbook only player) and give it SACD and DVD-A capabilities,theoretically??? Or does this just provide better resolution for the players that allready have SACD and DVD-A capability???

 

[Icy006]

Quote:

Originally Posted by Mikey01 Sorry! I am getting lost in the techno talk here. (slow learner) So, it may be possible to put this puppy in the Eastsound E5 (a redbook only player) and give it SACD and DVD-A capabilities,theoretically??? Or does this just provide better resolution for the players that allready have SACD and DVD-A capability???

This mod was done to address an issue with SACD and DVD-A players. It can't upgrade your redbook-only player (as SACD and DVD-A use different spindle speeds, laser wavelengths, decoders, and so on).

The problem with SACD and DVD-A is that there is no standard available to output high resolution digital bitstreams (if we discount the firewire thing), such as one would use to hook up to an outboard DAC. If you ever see a S/PDIF out on a SACD or DVD-A player, it's only there to output redbook-resolution audio.

With the mod board installed, you get three high-res stereo S/PDIF streams out of your SACD/DVD-A player (one per front left/right, rear left/right, and center/sub - but you only need the first one for stereo material).

Personally, I want to run as little analog cabling as possible, and also want to be able to hook up all of my digital sources to a single DAC - and that's why this thing intrigues me.

 

[Icy006]

Quote:

Originally Posted by myhui Pick off the DSD stream from the commercial SACD player, both clock and data, and send a short burst of it into a computer when a SACD with just a test tone is playing. Then use your knowledge of delta-sigma modulators to process it in software, to turn it from DSD into PCM. Once you get it right, design a logic circuit that can do the same thing in an FPGA. Then sell the FPGA on a board, with DSD inputs at one end, S/PDIF outputs at the other end.

You'll notice that these guys used an ASIC chip. I'm not up on what is available in the FPGA market these days, but I dunno how feasible it is. We're talking some serious clock speed to handle conversion in realtime. The faster FPGAs cost an arm and a leg. Hell, a micro might even work for this, though.

Quote:

Originally Posted by myhui A variation on this method is how you can, one day, with a lot of effort, convert a PCM-only, flash memory-based music player into a SACD capable one. The capture to computer part is all you need for this project, since you can simply replace the DAC in the player with a DSD-capable DAC, and have the music player's CPU send DSD output to the DAC instead of PCM, with a corresponding bit rate adjustment.

Ooh, cool idea. If you're already sending a DSD stream to your computer, though, why not just convert to PCM? That way, you can chuck it right to your portable without any DAC tinkering, if it supports high res already. I wouldn't try this with a flash-based player though. The biggest flash players on the market right now would yield less than one album in high res

 

[myhui]

Quote:

Originally Posted by Icy006 You'll notice that these guys used an ASIC chip. I'm not up on what is available in the FPGA market these days, but I dunno how feasible it is. We're talking some serious clock speed to handle conversion in realtime. The faster FPGAs cost an arm and a leg.

The ASIC is from Actel, an FPGA manufacturer. They prototyped it in FPGA, then handed the design back to the manufacturer to turn it into a hard-programmed chip so no one can copy the design by cloning the fuse pattern on the chip. It also makes volume production possible.

Quote:

Originally Posted by Icy006 Hell, a micro might even work for this, though.

If you say an FPGA might not be fast enough, a micro will definitely not be fast enough.

Quote:

Originally Posted by Icy006 Ooh, cool idea. If you're already sending a DSD stream to your computer, though, why not just convert to PCM?

The storage requirements is the reason you don't convert it to PCM in the computer first, and then download the PCM to the media player. DSD is the ideal format to store this type of information. Expand it to PCM at the DAC upon playback, not before.

 

[Jon L]

LOL. These guys say,

"S/P-DIF is the ideal way to transport audio signals in your HiFi or hometheatre system since there is no loss of quality. S/P-DIF transports the audio signals completely unchanged as they are stored on your digital media."

SPDIF is the worst possible way to transport digital audio. I most definitely would NOT buy any product from a company that either believes the above statement or pretends to believe it.

 

[Oliver :)]

Quote:

Originally Posted by Jon L SPDIF is the worst possible way to transport digital audio. I most definitely would NOT buy any product from a company that either believes the above statement or pretends to believe it.

Maybe this is meant in a practical way?