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bluecrab

MD as DAC question

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What exactly happens when an MD deck is being used as a DAC and receives a digital signal? For example, if you take optical out from one MD deck and feed it to optical in of another. Does ATRAC become involved? I'm not that great at schematics, but I looked at the SM for MDS-JA20ES and it does look like all digital in gets routed through the ATRAC chip. It seems unlikely that an already decoded signal would be decoded/processed again, but....does anyone know?

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As you know, only few decks (MZ-W1 for the most famous but also some professional decks like the E10) can make a real copy of an MD. Digitaly connected to another MD deck copy is possible one time if I remember well, due to SCMS limits. But another gentle SI member will be better than me for all the details. analog copy is Ok. Anyway digital or analogic, the Atrac compression will act again...

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Sorry, Philippe. What I am trying to ask (because the subject was brought up elsewhere) is whether ATRAC comes into play when one is using the MD deck as a DAC. So I could also give the example of taking the optical signal from a CD player and passing it to the MD deck. Although I don't see where ATRAC would be involved, it has been suggested that it does. Sorry for any confusion! (I am of course well aware that Copying is an entirely different process than what I am referring to.)

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Absolutely not. There is no ATRAC decoding/encoding for signal that passes through, the ATRAC only affects stuff going to/from disk.

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Good to know. I'd wondered about this when trying to work out the best way of connecting a couple of MD decks and a CD player to my PC audio interface. Sounds like I wouldn't lose anything by routing the CD player through one of the MD decks and eliminating the need for a separate digital switch. 

Might be able to reduce the amount of wires and boxes I have set up in my office now :)

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Exactly, BearBoy. It would never even have occurred to me that an MD's D.In might send everything to be processed by ATRAC. However, when that possibility was suggested to me, I thought it best to look into it further. It may even be that all digital in on an MD deck does go through the IC containing the ATRAC processor...but that doesn't mean ATRAC is necessarily doing something to that signal. At least, according to my totally guess-like interpretation of the schematic for the JE530 in this regard. (Seriously no more than a semi-informed guess.) Thank the heavens for sfbp! ;-)

That all said, I have two MD decks I am using not only as decks, but as DACs: JA22ES and JB930. Coincidentally or otherwise, these units have a DAC in common (CXD-8735N). It's all kind of mish-mish and I often have to use an xls I made to determine which piece goes where, but it all, happily, works out.

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PC laptop optical out ----> JB980 ----> Cyrus IIIi

I rather use my JB980 as a DAC not before but between my PC (so I can record directly fromPC) and my amplificator (Cyrus IIIi). I can even record SACD files if I downgrade the quality to 48kHz or if I use an analog connection.

PC desktop (player JRiver Media Center, Hi-Res settings, 1000 SACD/DSD/DFF albums + ) toslink optical out --- 24bit-192kHz coaxial output ---> Yamaha DSP-AZ1 (5.1, good enough...)

PC desktop (toslink optical out , using a splitter) ----> JB930 (future) tolslink optical in ----> Yamaha receiver

Marantz 5001 CD player coaxial optical out ----> JB930 (future) coaxial optical in  ----> Yamaha receiver

I don't have any use of your configuration (CD ----> MD deck before PC) in my major audio system as my CD player is a modern one so it has as a 24bit/192kHz DAC inside and the receiver (incredible old Yamaha DSP-AZ1) as also a coaxial input connection set to 192kHz. In my major configuration, a MD deck could be only use just to listen MDs and to record MDs from the CD player directly. I would need to buy an optical out PC splitter (PC ---> receiver + PC --> MD). I will do that when my JB930 now in france will joint my JB980 in Vietnam.  

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Just to follow up I double-checked with a schematic of one deck (the 980 but others are I am sure identical), you will see a path from DIN to DOUT that does NOT involve going through the block marked "ATRAC encoder/decoder".

The only caveat is that the DAC doesn't work when there's no (BD) drive in the unit, as I discovered to my cost one time I had to get a drive fixed. Because that circuitry is IN the disk assembly's circuit board.

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Thank you for confirming that, Stephen.  I could not be sure that my perception was correct. So the IC containing the ATRAC chip isn't involved at all? BTW, The one deck I have (actually I have 2 of them) that lacks the pass-through DAC functionality is the MXD-D400. Although I found this out at no cost to me, I was disappointed.

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19 hours ago, bluecrab said:

I was disappointed.

By what, the sound quality comparing CD to PC vs CD to DAC to PC ?

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Well, the MXD-D400 isn't on the same level of playback SQ as, for example the JB930—but I knew that. It sounds acceptable and does have Type S. No, what I mean is that you can't use the D400 as a  DAC like you can with most decks. That and it doesn't have demo mode. Seems odd because the lesser MXD-D40 has both of those features.

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It got rewired to allow playback of both MD and CD through the optical out, I think. Will look later.

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