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Old 1st December 2002, 08:18 AM   #11
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skaara:

Yes, DIR1703, 1203 was a typo. But which one should I take?
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Old 1st December 2002, 06:02 PM   #12
skaara is offline skaara  Slovenia
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If cs8420 offers anything more inyour dac than dir 1703 use cs8420 otherwise use dir1703..
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Old 12th December 2002, 09:01 PM   #13
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pquadrat:

>>I do not want to decode the DD signal, just get the already decoded I2S data stream out of the player to a different DAC. And not even for DD or any multi-channel, only for DVD-A and SA-CD.

>>And about licence: Don't want to sell this, and I don't care what the industry dislikes to be done. I take the right to use any bit that's on the disk, I paid for it. I don't want to copy anything. Just listen to the recording, with equipment I can trust."


If all you want to do is pull of the digital output data stream, that's not too difficult. You just need to get the spec sheets for the processor that's used. The hard part is wading through the spec sheets (for our project we had about 3,000 pages of spec sheets and application notes printed out). Also, figuring out what type of output mode the DSP is set in would be a trick, as that is done through the uC and a serial programmable interface (i.e. you can't tell by just looking at the schematics of a few mode setting pins like on a CS8412/4). Most of the processors we looked at (Zoran, Motorola, Cirrus, Sanyo, and a few others) had an option for I2S, but as with most DACs, there are several other modes that the user can use.

As for the licensing, Dolby, DTS, Microsoft (now owners of HDCD), and the developers of DVD-A format DO care about licensing. There is a HUGE paper trail of forms to fill out just to get some samples or an evaluation board for Dolby processors. On the flip side, DTS was pretty cool about it for our project. You can't even get an evaluation board without signing 2 or 3 waivers. Dolby and DTS both have a licensing fee just to go through the design process/development with a DSP with their algorithm on it. Then on top of that you have to pay licensing fees for each unit that is sold (when the design eventually does go into commercial sales). Yes, its ridiculous, but that's the way it is. So, for those of you out there who are wanting to get your hands on the actual DSP for DD, DTS, HDCD (an interpolation filter in this case), good luck unless you have a couple $million for licensing as I mentioned before (or a good inside source at Cirrus ).

That said, pquadrat, I'm fine with making it modular. I'm just not sure what you mean by adding a "DSP Module" on it.

Hey, I also just had an idea ! I found a MUX that would be pretty cool to integrate also - it would allow a user to switch the 4 clock and data lines (LRclock, master clock, bit clock, and data) between two different DACs... this would be really sweet for direct comparison. The chip is by IDT, model # QS3384. By having a center off SPDT switch mounted on the case, it would be really easy to implement (I think). Cirrus uses this chip in their eval board for the CS4396 DAC. It allows the user of the eval board to switch between the SP/DIF lines extracted from the on-board CS8414 and an external DSD (Direct-Stream-Digital) input from an SACD player module. Pretty slick, I think. Lemme know if you think this has any merit or not.
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Old 13th December 2002, 12:06 AM   #14
skaara is offline skaara  Slovenia
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Thieftoner: So the dac chip and the decoder for dvd-a and dts are in the same chip so you cant pull out the digital data to use it with other dac?
Can we use chips that are already in dts players and took their data for our dac? If so, we dont need millions for licensing..
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Old 13th December 2002, 12:39 AM   #15
BrianGT is offline BrianGT  United States
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For SACD, TI has a couple of DSD dacs. I got a couple of samples of their DSD1700 a couple of weeks ago, but I don't see a samples button for it anymore. Maybe it will come back soon. I have 3 of them, and can part with one if anyone needs one to play around with one.

Datasheet:
http://www-s.ti.com/sc/ds/dsd1700.pdf

What about hacking apart a dvd player to get dd/dts/sacd components? I bought a sony NS500V from bestbuy for $120 (open box) and it has all of those chips inside it. A link to the service manual has been posted on the forum:
http://www.diyvideo.com/forums/showt...=&postid=95089
Would it be possible to modify this player, upgrading all of the components, instead of trying to make your own with impossible to obtain chips?

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Old 13th December 2002, 02:15 AM   #16
jwb is offline jwb  United States
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The DSD1700 is easy to obtain. Send $15.94 plus shipping and handling to Digi-Key. Cake.

I've found that most low-end DVD players are using highly integrated processors, like the National thingy with five zillion pins. Sometimes it can be hard to get the datasheets.
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Old 13th December 2002, 03:22 AM   #17
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skaara:

>>Thieftoner: So the dac chip and the decoder for dvd-a and dts are in the same chip so you cant pull out the digital data to use it with other dac?
Can we use chips that are already in dts players and took their data for our dac? If so, we dont need millions for licensing..


The processor that decodes DD, DTS, MPEG, etc. typically sends out PCM data streams

- master clock (this may be pulled off of a DIR, depending on the processor and if it is operating in a slave mode)
- frame sync (otherwise known as L-R clock)
- bit clock
- and 3 stereo data streams (for 6 channel surround sound)

This PCM stream can be passed in I2S, left-justified, right-justified, or whatever else the processor supports. Often there are several options for this. The problem is knowing (1) which pins on the processor are what, (2) figuring out what mode the processor is outputting the data streams in (left-justified, I2s, etc). The difficulty in figuring out which mode the processor is in is near impossible because it is programmed through an EPROM or uC serial interface upon boot-up.

For the record, I have no experience with DVD-A processors. I can't imagine there's much of a "processor" though.

If one can gain access to the DACs in a reciever, DVD player with multichannel decoding, preamp, etc... then perhaps one can find out what mode the built-in DACs are running in, thus knowing what mode the main DSP is outputting the multichannel information in. Then, theoretically, one could tap these lines and run to a better designed DAC module.

Theoretically, its shouldn't be all that difficult, such as Dorkus' mods to the Sony NS-500V DVD/CD/SACD player DAC outputs. In this case, he knows that the DACs are made by AKM. With some initiative (not that I'm saying he hasn't had any with his previous mods) he could tap the data and clocking lines that are sent to the multichannel AKM DAC. Using these, he could run it to a Cirrus 4226 or equivalent for experimentation. The information is there on the boards, one just needs to find it.

Hope this helps!
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