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, to switch between I2S and DSD signals. However when I tested I2S out, I did get a lock on my Buffalo DAC, but only sound through the right speaker with a LOT of noise (more noise than music) and no sound from the other channel (left). In my noob ignorance I totally went by the possibility that maybe the DVD2200 does not put out true I2S but maybe a left justified or right justified PCM stream.
The decoded signals, as well as the red book CD signal, come from an M65776BFP MPEG decoder chip (cannot find datasheet) . 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, audio decoder/bass management chip (also no datasheet to be found), from where the front L/R signal goes to the same multiplexer (which is switched by a signal from the MPEG chip).
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 on the multiplexer get the same signal(so if the multiplexer introduces any delays, they should be the same as the data stream). All signals however first go through an SN74LV244 buffer, before the multiplexer.
I've tapped the signals directly after the multiplexer.
![denon_dvd-2200_[ET] 133.jpg](https://www.diyaudio.com/community/data/attachments/156/156823-94a3ffa131e1a688ae657c0a7343ed05.jpg?hash=lKP_oTHhpo "denon_dvd-2200_[ET] 133.jpg")
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.
Does anybody have an idea on what kind of signal these chips put out and what the influence of the SN74LV244 buffer is on the signal? I guess all signals are delayed in a similar manner by the buffer, so the signal out of the buffer is the same as going in (timewise).
If the signal from the MPEG decoder is left justified or right justified, what are the possible solutions? I was thinking about reclocking with a Twisted Pear Metronome. But before doing that, or anything else, I want to make sure I understand somewhat better what is going on..
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, to switch between I2S and DSD signals. However when I tested I2S out, I did get a lock on my Buffalo DAC, but only sound through the right speaker with a LOT of noise (more noise than music) and no sound from the other channel (left). In my noob ignorance I totally went by the possibility that maybe the DVD2200 does not put out true I2S but maybe a left justified or right justified PCM stream.
The decoded signals, as well as the red book CD signal, come from an M65776BFP MPEG decoder chip (cannot find datasheet) . 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, audio decoder/bass management chip (also no datasheet to be found), from where the front L/R signal goes to the same multiplexer (which is switched by a signal from the MPEG chip).
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 on the multiplexer get the same signal(so if the multiplexer introduces any delays, they should be the same as the data stream). All signals however first go through an SN74LV244 buffer, before the multiplexer.
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.
Does anybody have an idea on what kind of signal these chips put out and what the influence of the SN74LV244 buffer is on the signal? I guess all signals are delayed in a similar manner by the buffer, so the signal out of the buffer is the same as going in (timewise).
If the signal from the MPEG decoder is left justified or right justified, what are the possible solutions? I was thinking about reclocking with a Twisted Pear Metronome. But before doing that, or anything else, I want to make sure I understand somewhat better what is going on..
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