OK!
So I am naive, it seems.
my DAC (we'll call it a SRC2496 for now) doesn't accept 96kHz (or 88kHz for that matter) PCM on its AES input, but the coax input does... interesting
now it's all working (as it likely was before) at 96kHz output, except for a few pop sounds in the audio.
my next question, since even a "192kHz" DVD-Audio seems to be only 96kHz, do I really need the ASRC to handle this, or is there a true 192kHz DVD format?
Maybe I don't need the ASRC for this application, as I'd like to avoid the pops
.
So I am naive, it seems.
my DAC (we'll call it a SRC2496 for now) doesn't accept 96kHz (or 88kHz for that matter) PCM on its AES input, but the coax input does... interesting
now it's all working (as it likely was before) at 96kHz output, except for a few pop sounds in the audio.
my next question, since even a "192kHz" DVD-Audio seems to be only 96kHz, do I really need the ASRC to handle this, or is there a true 192kHz DVD format?
Maybe I don't need the ASRC for this application, as I'd like to avoid the pops
.
The format of the Oppo digital audio connector is left-justified.
It sounds like there is something wrong with the AES input to your SRC2496. Also, you may try removing the voltage divider on the SPDIF output of the Wolfson SPDIF board.
In my mods, I made the wires from the Oppo to to my mod board much shorter. Try twisting them with the ground wire.
Twisted pairs have good noise immunity because the signal return currents and the signal forward currents have equal but opposite EM fields and those fields can cancel. That isn't very important at DC but it is important at megahertz frequencies.
I'm not familiar with the jumpers for the metronome, it looks like the Wolfson board is set up OK.
It sounds like there is something wrong with the AES input to your SRC2496. Also, you may try removing the voltage divider on the SPDIF output of the Wolfson SPDIF board.
In my mods, I made the wires from the Oppo to to my mod board much shorter. Try twisting them with the ground wire.
Twisted pairs have good noise immunity because the signal return currents and the signal forward currents have equal but opposite EM fields and those fields can cancel. That isn't very important at DC but it is important at megahertz frequencies.
I'm not familiar with the jumpers for the metronome, it looks like the Wolfson board is set up OK.
Thanks Ross, yes I figured the Left Justified.
In clarification of my previous post, the problem with 96kHz is due to the CS8420, with its known bugs. I'll be doing away with the SRC now that I have a good working source for all types of discs.
In clarification of my previous post, the problem with 96kHz is due to the CS8420, with its known bugs. I'll be doing away with the SRC now that I have a good working source for all types of discs.
Pulse-R said:
It looks like you have it setup correctly.
I seriously doubt the pops are coming from the ASRC itself, more likely something down stream. Wiring as Ross said is probably the sticky point here.
Good work so far. I think it will work out.
Cheers!
Russ
schematics
Hi,
Where can I download the Pioneer schematics that are similar to the Op's ?
Thanks.
Hi,
Where can I download the Pioneer schematics that are similar to the Op's ?
Thanks.
Hi All, I was wondering - with the 981 Oppo, it seems that the +5v power is always on - even in sleep mode.
Is there a source for the 5v in there which goes off with sleep mode??
or alternatively, another signal which can be connected to the WM8804 to tell it to go to sleep...
TIA
Simon
Is there a source for the 5v in there which goes off with sleep mode??
or alternatively, another signal which can be connected to the WM8804 to tell it to go to sleep...
TIA
Simon
I think that turning off the Oppo only turns off the blue front panel display and powers down some auxilliary circuits.
You may want to check the power for the display and see if that is a suitable power source for the Wolfson board. I have not investigated it.
The MT1389 chip is powered up all the time and the oscillator runs 24/7. I like it this way because the low jitter oscillators on my mod board run continuously. It may be all psychological, but I think the 8421 ASRC on my mod board sounds better when the clock is powered up for a week or more nonstop.
You may want to check the power for the display and see if that is a suitable power source for the Wolfson board. I have not investigated it.
The MT1389 chip is powered up all the time and the oscillator runs 24/7. I like it this way because the low jitter oscillators on my mod board run continuously. It may be all psychological, but I think the 8421 ASRC on my mod board sounds better when the clock is powered up for a week or more nonstop.
On second thought, it may be better if the Oppo display power supply was used just to disable the Wolfson chip.
The cathode of a diode connected to the display + power source and the anode connected to the RESETB connection of C9 and R8 on the Twisted Pear SPDIF board.
That way, when the Oppo blue display is powered down, the Wolfson chip is held in reset.
It could work but I haven't tried it.
😀
The cathode of a diode connected to the display + power source and the anode connected to the RESETB connection of C9 and R8 on the Twisted Pear SPDIF board.
That way, when the Oppo blue display is powered down, the Wolfson chip is held in reset.
It could work but I haven't tried it.
😀
thanks rossl, will have to poke around next time I have the lid off.
will be installing pcb pins and sockets for the clock/data lines off the Oppo board at the same time, to make experimenting a bit easier...
busy building speaker stands at the moment 🙂
will be installing pcb pins and sockets for the clock/data lines off the Oppo board at the same time, to make experimenting a bit easier...
busy building speaker stands at the moment 🙂
vizion said:
The Oppo isn't 2 inches high.
It is about 1.5 inches on the outside of the case. Inside will be a bit less.
MrMajestic said:
Eh, never mind. I was tired when reading the thread. Realise now that its the twisted pear SPDIF receiver I should use.
I have question. Would I be pushing the limits of the i2s bus if I would skip the SPDIF transceiver to run i2s on a shielded CAT5 cable to an external DAC? I have an Opus DAC that I would connect it to. They would be stacked on top of each other so the cable wouldnt have to be very long.
I think you would need to buffer the I2S output - I have seen the I2S on some transports, IIRC they were buffered by a tri-state device 74HC cmos...
Pulse-R said:
Ah yeah, that might be correct. Im probably better off using the TP SPDIF board instead then. thanks for the reply.
Hi Ross!
It's been a long time, but I've finally gotten around to installing my board into my Oppo. I'm almost done, but I want to know - how did you remove the crystal on the Oppo board? Did you just pry it off? I don't see a way to get my soldering iron onto the pins underneath the "can".
Thanks!
Ted
It's been a long time, but I've finally gotten around to installing my board into my Oppo. I'm almost done, but I want to know - how did you remove the crystal on the Oppo board? Did you just pry it off? I don't see a way to get my soldering iron onto the pins underneath the "can".
Thanks!
Ted
Just grab the crystal with needle nose pliers and twist. It comes right off.
It's not elegant, but it works
😀
It's not elegant, but it works
😀
Thanks, Ross!
That was a real point of no return moment, since up to that point I felt I could restore the Oppo to its pre-mod condition if needed. This is the first time I've taken my soldering iron to a perfectly operational piece of equipment that was a central part of my system, so I had to bite the bullet, so to speak!
Well, the good news is that when I put everything back together last night, it worked! First I verified that I could still play standard CD out of the coax connector on the player, then switched over to the new connector (I chose to implement SPDIF output through a 75-ohm BNC connector). Then I put in my first SACD - Prokofiev's Romeo & Juliet from Telarc. After loading up for a few seconds, wonderful music suddenly began playing! Hooray!
I have to admit that it'll take a week or two of problem-free playing before my worries subside (worries that I screwed up my ~$300 player, not that the design has issues). But so far it looks like a great success!
Thanks again to Ross for offering this project to unleash the capabilities of the Oppo!
Ted
That was a real point of no return moment, since up to that point I felt I could restore the Oppo to its pre-mod condition if needed. This is the first time I've taken my soldering iron to a perfectly operational piece of equipment that was a central part of my system, so I had to bite the bullet, so to speak!
Well, the good news is that when I put everything back together last night, it worked! First I verified that I could still play standard CD out of the coax connector on the player, then switched over to the new connector (I chose to implement SPDIF output through a 75-ohm BNC connector). Then I put in my first SACD - Prokofiev's Romeo & Juliet from Telarc. After loading up for a few seconds, wonderful music suddenly began playing! Hooray!
I have to admit that it'll take a week or two of problem-free playing before my worries subside (worries that I screwed up my ~$300 player, not that the design has issues). But so far it looks like a great success!
Thanks again to Ross for offering this project to unleash the capabilities of the Oppo!
Ted
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