Question about CD output

Discussion in 'Archived Threads 2001-2004' started by RyanFrank, Jun 6, 2002.

  1. RyanFrank

    RyanFrank Auditioning

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    Hi everyone

    I'm a newbie here, so bear with me if I'm off topic or not being clear.

    I've been debating something with a friend, and thought I'd get some feedback from some knowledgeable people, hence this post.

    My case is this: pure CD players for the home these days have a couple options when it comes to getting the data/sound to the A/V receiver: it can sent in an analog format (DAC done in the CD player), or it can be sent digitally (DAC done in the A/V receiver). I would think that the cleanest method with the least amount of noise introduced into the system would be doing the DAC in the A/V receiver - keep the data in digital format until the very last step, then do the DAC. Does this sound correct?

    If my above hypothesis is correct, then why would a person buy an expensive CD player? I understand that error control differs among CD Players, but after about $200, you are not going to get much more bang for your buck. A $200 CD player can extract the same 1's and 0's as a $1000 CD player. And if you do the DAC in the A/V reciever, then I would say it makes no difference which CD player you use.

    So what do you think? Sound reasonable?

    Thanks for reading and any comments you may have.

    Ryan
     
  2. John Royster

    John Royster Screenwriter

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    A person would buy an expensive CD player for its sound and DACs. In general the DACs in even modest CD players in the 300 and up range blow the doors off the DACs in most all receivers (notice I didn't say all [​IMG] ).
    Sounds like you've got it all down.
     
  3. John Royster

    John Royster Screenwriter

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    One last thing. You said a 200 dollar player can extract 1s and 0s exaclty the same as a 1000 dollar player. This is not entirely true.
    Biggest difference by far is the DACs in a good player and is readily noticed when listening. Hearing differences between transports is very subtle.
    So do you have some ammo for your disagreement with your friend? Absolutely! Unfortunately i think it supports his side[​IMG]
    If you need some more info do a search of this forum on "transport". If your friend is searching for a good CD player and doesn't have a flagship receiver, he'll probably be better off using the analog outputs of said nice CD player.
     
  4. Rob Roth

    Rob Roth Stunt Coordinator

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    Think of it this way: A manufacturer has a receiver with, say, 5-8 digital inputs. Each requires DACS, and analog inputs may require ADCs. How much can the mfr. spend on these devices? A CD player can have one good set of DACS without busting the bank.

    A second consideration is jitter. Anytime you have digital transmission via a cable from one stage to another you run the risk of introducing timing errors. CD players, even more than separates, minimize jitter by keeping all the activity in one box.

    For less expensive CD players your point is probably correct; the DACS in the receiver may be better than those in the player.
     
  5. GordonL

    GordonL Supporting Actor

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  6. Thomas Newton

    Thomas Newton Screenwriter

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  7. Rob Roth

    Rob Roth Stunt Coordinator

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    How would a receiver accomplish multizone operation with a single set of DACS?
     
  8. KeithH

    KeithH Lead Actor

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    One of the common misconceptions in audio is that all CD players sound the same when used as transports (i.e., when using the digital outputs). As John said, this is not true. When it is observed that one player sounds better than another when using the analog outputs on both, the difference should not be assumed to be entirely explained by the difference in DACs. That is another, and related, misconception. When using the analog outputs, there is the respective quality of the analog output stages to consider. Also, and this relates to the quality of the players as transports, there is the solidity of the transport mechanisms, jitter reduction circuitry, chassis dampening (vibrations), and a host of other factors relating to overall build quality to consider.

    High-end systems can readily bring out the differences in players as transports. I am not talking about $200 versus $1000 players here. A high-end system can bring out the differences between two $2000 transports. As a lower-end example, take my experience comparing a Pioneer CLD-D406 laserdisc player to a Sony CDP-CA80ES carousel CD changer. I used to have these two components in my home-theater system, which served as my main audio system at the time. These components were connected to a Sony STR-V444ES A/V receiver and Energy e:XL 16 bookshelf speakers. In comparing the 'D406 and 'CA80ES as transports, it was no contest. The 'CA80ES was far, far better. The 'D406 was putrid. I was very surprised at how significant a difference there could be between two low-to-mid-fi components in a mid-fi system.
     
  9. RyanFrank

    RyanFrank Auditioning

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    I'd like to thank everyone who took some time out to address my question... Thank you. Your comments were very insightful.

    Seems that the general concensus is to let a quality CD player do the DAC and send out an analog signal. Sounds good to me!

    Still, and forgive me if I misread some of your comments, how about a little thought experiment. Take a bargain brand El Cheapo CD player and a top of the line Rolls-Royce CD player and hook them to the same A/V receiver using digital transports. Which will sound better? I think of a CD as having a bunch of 1's and 0's that can be read; both CD players can read the 1's and 0's and send them in a bitstream to the receiver. I know errors can occur while reading the data and most CD players have some kind of error checking (the more expensive models will have better error checking), and the El Cheapo model may mechanically fail sooner than the Rolls Royce, but if we assume that both are functioning a peak efficiency, I can't see how they would sound different. The bitstreams going to the receiver would be identical, correct?

    What do you think?

    Many thanks for your comments.

    Ryan
     
  10. KeithH

    KeithH Lead Actor

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    Ryan, I forgot to welcome you to the Forum before, so welcome! In the end, you have to compare the sound quality of your CD player when using the analog and digital outputs. There are no hard and fast rules. The relative performance will depend on the player, external DAC, speakers, and cables. Generally speaking, the more you spend on a player, the better will be the sound using the analog outputs. However, usually as you spend more money, you get a better transport as well. Of course, as you spend a good bit of money on a player, you have to have amps and speakers that are up to snuff to realize the benefits that the player can offer in the first place.

    If you compare a $200 player and a $2000 player as transports, you may not hear a difference if you are using cheap associated gear. Again, the other equipment has to be up to snuff. A $500 A/V receiver and $500 speakers likely will not do the $2000 player justice, whether you are using the analog or digital outputs.

    In a revealing system, you absolutely should not assume that a cheap player and a "Rolls-Royce" player will sound the same as transports. Both players are reading and transmitting 1s and 0s for sure, but what you need to consider is jitter (timing of the 1s and 0s to get where they are supposed to get to), interference from poor quality and/or poorly laid out circuitry, isolation (dampening), etc.
     
  11. GordonL

    GordonL Supporting Actor

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  12. KeithH

    KeithH Lead Actor

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    Gordon, jitter applies to the transport, and other circuitry and can interfere with the digital signal. Poor isolation and dampening of the transport can cause problems as well. When using a player as a transport, there are plenty of design elements that need to be "right" on the player end. Certainly, plenty of things need to be right on the DAC end as well, and in between (the cable).
     
  13. Karl L

    Karl L Agent

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    I currently have a Marantz SA8260 SACD player on order. It will be paired with a Pioneer Elite 49-tx receiver. For redbook playback would I be better off using a digital or analog connection? The Marantz supposedly has state of the art dac's, but I'm sure the ones in the Pioneer aren't to shabby themselves. If I go analogue and then use the multi channel adjust feature in the Pioneer to do bass management, would I not be using the dacs in the Marantz to their full effect? Guess I'll figure it out in a week when the player shows up, but in the meantime I'm curious as to what you guys may think.
     
  14. Larry B

    Larry B Screenwriter

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    keith said

     
  15. Chris PC

    Chris PC Producer

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    What is a transport mechanism and what does it do? I think I have a mis-understanding of what a transport mechanism is and what it does.
     
  16. KeithH

    KeithH Lead Actor

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    Chris, the transport is the portion that holds the disc and also reads it and transmits digital information. I am no engineer, so I am giving a more layman's view.
     
  17. Lewis Besze

    Lewis Besze Producer

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    Well the other missconseption that DAC's are expensive, the BB dacs in the Sony 555 ES cost about $5.00 each!
    So much for the analogy that the same price CD player presumably has a superrior dac over a receiver[similar price range] due to price.
    The real money is in the hardware[mechanical moving parts,power supplies, capacitors, transistors etc....].
    To me the real difference between CD players are lies in the analog section,since most everybody use off the shelf digital parts.
     
  18. KeithH

    KeithH Lead Actor

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    Lewis, agreed. Most everyone it seems says that when one player sounds better than another, it is due to superior DACs in one of them. In some cases, this is a contributing factor, but it is an overly simplistic view. I often point out that the recently discontinued $180 Pioneer DV-440 uses a 24/192 Burr-Brown DAC. Obviously, the '440 is not a world-class CD player. The analog output stage, transport, power supply, and overall build quality are all likely to be lackluster in a $180 DVD player.
     
  19. Chris PC

    Chris PC Producer

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    OK, so the transport includes the mechanism like the drawer and the spindle that holds the CD, the laser and the electronics that produce the 0's and 1's from the CD ?
     
  20. Lewis Besze

    Lewis Besze Producer

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    aha.
     

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