Poogeing the SACD: The Pioneer 563A

[KBK]

As far as I can tell, there is a third divider on this board for the audio clock into the Philips SAA7893HL SACD chip at pin 29. Taking a quick look at the manual, it may be storing the DSD and audio data in a nearby (opposite side of the processor board) 64mbit sdram module, and pulling the data at the needed times. The divider and the memory sdram are beside eachother, and the tech manual seems to indicate that this NEW DESIGN, second generation SACD multi-process capable chip can take a variety of clocking frequencies and dividers.. so maybe the PLL is not needed? It may just use the master 27mhz clock?

The chip usage block diagram shows a PLL, but there is none that I can see on the Pioneer board. there is apparently a possible spot for it, as the silkscreened numbers on the board itself seems to indicate it (the Pioneer processor board) is an other Pioneer models as well, like the 565 and 566 (if they even exist).

Not knowing anything about all this modern Digital Stuff I will ponder out loud: ....Also, since it is SACD/DVD-A/CD all in one chip.. it may be doing a upsample-process-DAC-downsample trick of some sort, and may not need or use the expected clock frequencies. At least the CD 44.1k and DVD-A 96k stuff may be upsampled, is what I mean,and then fed to the BB1791 at upsampled levels. Why bother with any other configuration?

Philips SACD SAA7893HL tech manual

[Vinnie R.]

Originally posted by KBK
As far as I can tell, there is a third divider on this board for the audio clock into the Philips SAA7893HL SACD chip at pin 29. Taking a quick look at the manual, it may be storing the DSD and audio data in a nearby (opposite side of the processor board) 64mbit sdram module, and pulling the data at the needed times. The divider and the memory sdram are beside eachother, and the tech manual seems to indicate that this NEW DESIGN, second generation SACD multi-process capable chip can take a variety of clocking frequencies and dividers.. so maybe the PLL is not needed? It may just use the master 27mhz clock?

Philips SACD SAA7893HL tech manual

Correct me if I am wrong here, but all I see is the 27MHz circuit, and it splits to feed 27MHz into IC701 (SACD IC) and 27MHz intoIC601 (back end IC). I believe that any freq. dividing needed is done inside these chips. All the clocking info used by the DACs is sent to them by IC701. And based on what I see on the schematics, there is NO DSD to PCM conversion. The L/R DAC is IC201, labeled DSD1791, and it inputs DSD or a PCM signal (depending on the format being played). IC601 outputs the SPDIF, along with video output signals.

In terms of clock jitter, like it was mentioned above, I think this is pretty much limited by IC701 and IC601's internal PLLs and such. I'm not sure how much improvement would come about if a really precise 27MHz clock was installed.

Also, I don't see where to beef up the power supply feeding the 27MHz clock circuit. The supply is V+3D, and for the 27MHz signal feeding IC601, it goes through L604 and then directly into pin 8 of the hex inverter type IC (used for buffering I believe). For the signal feeding IC701, the V+3D goes through L606 in a similar fashion to pin 8a different hex inverter IC (only one buffer is used on this IC). Did you add a cap from the pin 8;s of these ICs to GND to make this supply more stable?

[larry moore]

Vinnie:

Did ya get the schematic?

[Vinnie R.]

Originally posted by larry moore
Vinnie:

Did ya get the schematic?

Yes I did Looks great

Thanks again!

[ThorstenL]

Konnichiwa,

I have amused myself extensively with Chip Datasheets. Interesting. Can anyone who has the unit and ideally service manual check if the SAA SACD Chip is used to oversample all PCM to a DSD Datastream and to reclock or if PCM runs on a simple "passtrough"?

If the formaer, you can simply pick up the SACD Datastreams prior to the DAC Chip's for all signals and send them through a basic Bufferamp/Filter. This reputedly sounds pretty good (see Allan Wright) though I was underwhelmed by a machine modified in similar manner, for whatever reasons.

Secondly, for all europeans, the differences bewteen the 563 and 565 seem cosmetic, I have found several references suggesting that the 565 uses the same chipset as the 563 and I would guess mostly identical PCB's too... So all mods should translate well.

Sayonara

[KBK]

I could very much use that schematic myself, although at this point is is nearly not needed at all.

BTW, I have done my proprietary clock mod and the SACD chip responds as well as a regular 44.1 CD unit to such ministrations. It does indeed improve the machine dramatically when it comes to harshness and overall coherency. Before anyone asks, I cannot share it. I do apologize. After the patent is applied for, feel free. I will share then.

[net-david]

I also need the schematic if anyone would be so generous!

--David

[KBK]

Originally posted by Vinnie R.


Yes, the DV-45A uses this type of topology as well (27Mhz going into a freq. divider). How did you 'fix the divider's power supply' and did you attempt to alter the power supply lines to the BB DAC?
I'm hoping to start next week.

-Vinnie

DUH!

Vinne, oh wise one... you are making me smack my head! There is no need for the super long supply lines to the PS for the regualtors for the DAC. Cut the traces and run wires directly to the DAC's PS from the SMPS.

[Vinnie R.]

Originally posted by KBK



DUH!

Vinne, oh wise one... you are making me smack my head! There is no need for the super long supply lines to the PS for the regualtors for the DAC. Cut the traces and run wires directly to the DAC's PS from the SMPS.

Gee, do I detect some rudeness?

I was just trying to confirm what it exactly was that you did, for my and everyone elses benefit (if they are interested). Unless I am misinterpreting your intentions, you seem to be a little edgy. Are you working in a well ventilated area?

Getting back on track here, I just ordered a pair of Black Gate NX Hi-Q non-polarized caps (6.3V, 47uF) to replace the stock electrolytic output coupling caps. I've done the same thing a while back on a Sony NS500V and noticed a nice improvement in bass control. Has anyone else swapped out these caps with something else? I have to measure how much DC bias is before the cap to see if it can be completely bypassed. There is also a 200 ohm resistor in series with the output after the cap (used for the muting transistor circuit). I have bypassed these before in my DV-45A but got annoying popping sounds when opening/closing the door and changing tracks, and the 45A uses the same muting topology. A better solution would be using a relay instead of the muting transistors. I may do this, but I want to work on other things first that will probably yield a better improvement.

Regards,

Vinnie

[Vinnie R.]

Originally posted by net-david
I also need the schematic if anyone would be so generous!

--David

David,

When I get home from work I can try scanning them. Email me and I will reply with them. How big is your mailbox btw?

-Vinnie