Rank: Member
Groups: Member
Joined: 4/13/2010(UTC)
Posts: 19
Location: The Netherlands
|
I wanted to mod my Denon DVD 2200 to directly output DSD. While doing that, I thought it would be little extra effort to also get the I2S stream and make an automatic switch (internal switch doesn't switch the right signals, DAC inputs are different).
So I got the service manual. Found a nice spot to solder on my wires and got busy. DSD out worked like a charm on the first try (very nice, sound quality wise!). As did the automatic switching of my 4PDT relais (similar to OTTO), to switch between I2S and DSD signals. However when I tested I2S out, I did get a lock on the Buffalo, but only sound through the right speaker with a LOT of noise (more noise than music) and no sound from the other channel (left). The wires are still quite long and directly from the Denon main board to the DAC and I still have to test and try some possibilities, but maybe somebody immediately knows what's going on..
Thanks, Maarten
|
|
|
|
|
|
Rank: Administration
Groups: Administration, Customer
Joined: 10/24/2006(UTC)
Posts: 3,979
Location: Nashville, TN
Thanks: 25 times
Was thanked: 89 time(s) in 83 post(s)
|
Are you certain it is I2S? It could be left justified or right justified PCM.
|
|
|
|
|
|
Rank: Member
Groups: Member
Joined: 4/13/2010(UTC)
Posts: 19
Location: The Netherlands
|
That was indeed one of my thoughts. The decoded signals, as well as the red book CD signal, come from an M65776BFP (cannot find datasheet) MPEG decoder chip. The red book signal directly goes to a multiplexer (bypassing any signal processing), the DVD-A/DVD-V PCM signal first goes to an ADSPMEL322 (also no datasheet to be found), audio decoder/bass management chip, from where the front L/R signal goes to the same multiplexer. LRCK and BCK directly go from the MPEG decoder to the multiplexer and also from the MPEG decoder to the bass management chip. They are switched by the multiplexer, but both A and B input the same signal(so if the multiplexer introduces any delays, they should be the same as the data stream). All data and clock signals however first go through an SN74LV244 buffer, before the multiplexer (as do the DVD PCM data). I've tapped the signals directly after the multiplexer. Because I can't find any datasheets on the MPEG decoder and the bass management chip, I wouldn't know which kind of PCM signal they put out. I have no scope and no software PCM analyzer (if such a thing even exists :)), so no way of checking the type of signal. If the signal from the MPEG decoder is left justified or right justified, what are the possible solutions? Can both type of signals be converted by the Metronome? If the Buffalo register is set to decode these signals (for instance with a modified Volumite firmware), can a normal I2S signal (like from the MUX) still be used as well (of course with an OTTO like switch in between)? Thanks for the info, Maarten Edited by user Thursday, May 20, 2010 1:57:44 AM(UTC)
| Reason: Not specified
|
|
|
|
|
|
Rank: Member
Groups: Member
Joined: 4/15/2010(UTC)
Posts: 16
Location: NYC
|
Mfly wrote:That was indeed one of my thoughts.
The decoded signals, as well as the red book CD signal, come from an M65776BFP (cannot find datasheet) MPEG decoder chip. The red book signal directly goes to a multiplexer (bypassing any signal processing), the DVD-A/DVD-V PCM signal first goes to an ADSPMEL322 (also no datasheet to be found), audio decoder/bass management chip, from where the front L/R signal goes to the same multiplexer.
LRCK and BCK directly go from the MPEG decoder to the multiplexer and also from the MPEG decoder to the bass management chip. They are switched by the multiplexer, but both A and B input the same signal(so if the multiplexer introduces any delays, they should be the same as the data stream). All data and clock signals however first go through an SN74LV244 buffer, before the multiplexer (as do the DVD PCM data).
I've tapped the signals directly after the multiplexer.
Because I can't find any datasheets on the MPEG decoder and the bass management chip, I wouldn't know which kind of PCM signal they put out. I have no scope and no software PCM analyzer (if such a thing even exists :)), so no way of checking the type of signal.
If the signal from the MPEG decoder is left justified or right justified, what are the possible solutions? Can both type of signals be converted by the Metronome? If the Buffalo register is set to decode these signals (for instance with a modified Volumite firmware), can a normal I2S signal (like from the MUX) still be used as well (of course with an OTTO like switch in between)?
Thanks for the info,
Maarten I haven't tapped the i2s in the Denon, but I was able to get it out of my Philips 963SA without having any help from pictures or instructions from someone who did it before. You can definitely do this without a scope, Do you have the service manual for the Denon? I'm shooting in the dark here since I don't know this player, but I wouldn't look at the MPEG processor. Google is your friend. A quick search told me that the 2200 uses a Burr Brown 1791 DAC. Download the application notes for that DAC chip, and look at the pinout to see where the DSD 1, DSD 2, CLK and Digital Ground inputs are on the chip. Then take your multimeter, and try to find another place on the board that connects to those pins on the DAC chip. There might be some vias or test points that you can solder. I wouldn't recommend trying to solder wires to the pins of the DAC unless you are willing to risk bricking your player. Pulling the DAC chip and soldering to the pads is very tricky too, it is extremely easy to pull one of the pads. If you want i2s, you could use the exact same method to hunt that down as well. Once you find the points and get it working, you might want to consider desoldering the DAC chip, so that the signal isn't split into two processors. ChipQuik, available from digikey is great for desoldering surface mount chips. I've done it with and without ChipQuik, and I'll never desolder a surface mount chip without it again. Good luck. I know that when I did it, I breathed in deep and accepted that I might destroy my player, but it wound up working great. -Aaron.
|
|
|
|
|
|
Forum Jump
You cannot post new topics in this forum.
You cannot reply to topics in this forum.
You cannot delete your posts in this forum.
You cannot edit your posts in this forum.
You cannot create polls in this forum.
You cannot vote in polls in this forum.
