CD players, Receivers, and DACs (1 Viewer)

[Jim_T]

Hi all! Forgive my ignorace, I'm rather new at this, but from what I gather, a DAC is a digital to analog converter and it changes the digital signals from sources like CDs and MDs to analog signals that can be output through my speakers...is this correct? Now, I've seen a number of different specifications for DACs in various components, and I must admit I really don't know what makes a superior DAC. Is there a list somewhere ranking various DACs used by different manufacturers?
I ask all of this because I'm trying to build myself a nice HT/stereo system. I've ordered (before all the S&V hubbub began) the Japanese version of the Marantz SR7200, called the PS7200 here, which is essentially the same but doesn't have a tuner. I'm wondering how the DACs in this receiver stack up against those in some other CD/MD players/recorders, most specifically the Marantz CD6000-OSE or Sony MDX-D5C. If the DACs in my receiver are considered quite good, I could buy a cheaper CD player and just let the receiver handle the D-A conversion, right?
And if it's a case of just listening and judging for myself, can this be done through the headphone jack of the various CD units, or would I probably not be able to notice a difference using headphones? I ask because the stores I've visited don't really have everything set up for easy test listening - for speakers, yes, but they don't really have all their CD players hooked up and ready to go. Anyway, thanks very much in advance if you can help.
Jim

 

[KeithH]

Jim, you are right on about the function of a digital-to-analog converter (DAC). I have not seen a ranking of various DACs, but such a ranking would probably have little meaning because the DAC is not the only factor in determining sound quality. How it is employed in a component is very important. Circuitry design (layout and isolation to reduce interference), capacitors, power supply, etc. influence sound quality. We often talk about the quality of a DAC when discussing the quality of CD players or receivers, but that is an oversimplification of the issue. Two CD players that are priced the same and use the same DAC, may not sound alike. The quality of the analog output stage (i.e., the circuitry that the analog signals travel through after conversion from the digital domain) contributes to the sound quality as does the power supply. In short, some DACs are better than others, but there are other factors to consider.
In the end, the only way to determine whether the DAC in a CD player or receiver is better (or in one CD player versus another) is to listen to both. Run RCA cables and an optical or coaxial digital cable from a CD player to a receiver and compare the sound with the two connections using some of your favorite CDs. In doing so, make sure you engage the receiver's analog bypass mode when evaluating the CD player's analog output. The analog bypass mode prevents the incoming analog signals from being processed through the receiver's A/D and D/A converters. These extra conversions not only can degrade the sound quality, but obviously do not allow you to fairly assess the quality of the CD player when using the analog outputs.
I think a test using the analog and digital outputs on a Marantz CD6000OSE with the Marantz receiver would be interesting. As for the Sony MXD-D5C, are you sure it has a digital output? I am not sure if the 'D5C marketed in the US has a digital output. The reason I ask is that I own the MXD-D3 (just a single-disc CD tray instead of a stacked five-disc CD changer), and it has no digital output. The newer MXD-D40 has no digital output either. So, the issue with the 'D5C may be moot. If the 'D5C has a digital output, I would expect this connection to sound better with the Marantz receiver than the analog connection. Sony's mass-market components use average DACs and other parts and usually don't sound that great when using the analog outputs.
As for using headphones to evaluate CD players, you can do this with one caveat. Some CD players may sound better than others with headphones, but you will be evaluating the players' headphone output stages, which may not be representative of the sound that would be observed when comparing players via the analog outputs to amps with speakers. I would try to get salesman to set up CD players you are interested in with one amp and a pair of speakers to better evaluate them.
Best of luck and enjoy.
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My:
HT Pics ; Equipment List ; DVD Collection ; LD Collection
KeithH: Saving the Home Theater World Before Bedtime

 

[JerryW]

Keith is 100% correct. There are many factors involved when it comes to quality in CD playback.
A good example is my CDP-CE345. It's DAC isn't the best in the world (pretty awful is closest to the truth), so I used it exclusively as a transport to my Onkyo receiver. In that role it's satisfactory for casual listening.
For intensive listening I've been using my Pioneer LD player (CLD-99) and it's DACs. I would characterize it's DAC stage as mellow and relaxed or "warm". So for blues, jazz, most classical, soft rock, and other softer material it really excels. Even when using the Pioneer as just a transport I can tell much better clarity between it and my Sony CE-345. There's less distortion, more range, and an overall more musical sound.
So, yes, there's much more that goes into a quality CD player. But, and here's the caveat, how critical are you in your listening habits? If you're only buying a CD player for casual listening, or to crank out lots of heavy pop/rock/metal then it's possible that you may never notice the difference between a $500-$1000 player and a $100-$200 player (especially if you never use the player's DACs and use it's digital out only). It's really up to your listening habits and the material you play.
If you only want an inexpensive, general use transport I have my CD changer up for sale here at HTF in the Hardware For Sale forum: http://www.hometheaterforum.com/uub/...ML/002795.html
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September 11, 2001
"Those who died will always be remembered.
Those who killed will never be forgotten.
We who remain will not let it happen again."

 

[Jim_T]

My thanks to both of you for your answers.
Keith, you're correct about the Sony - it doesn't have a digital output, so I think I can pretty much rule it out. Jerry, I'm no audiophile, but I'm critical enough to have bought a Marantz receiver and Tannoy speakers, if that means anything. I listen to many different types of music, but must admit that I rarely just sit in my room and actively _listen_ to music - I'm usually doing something else at the time.
Anyway, I suppose I'll just have to go in and twist some arms until they allow me to hear a few CD players played through my receiver. In the interest of narrowing my search down a bit, do you think combo units (CD/MD or CD/CD recorder) are inherently bad for any reason? What I mean is, does squeezing two components into the same box necessarily mean that the quality of them suffers?
Thanks again, and sorry about the stupid questions...I am _totally_ new at this.
Jim