What makes a good dac or transport?

muncybob · December 2014

I'm still pondering a purchase of a cd player. Seen comments about players with good and even great dac's. I've also seen comments that lead me to believe that the transport mechanism is possibly just as important as the internal dac. If a unit is described as "uses twin Wolfson WM8740 DAC chips" what does this tell me? I've read enough to know Wolfson is a respected name, but is this particular chip one of their better ones? Is the dac in an Oppo 83 any better than the one in an Azur 740c since the Oppo is newer.I haver also read people saying they were not fans of upsampling and others say it makes a big difference..I'm so confused!

SCompRacer · December 2014

Digital is complicated. To understand it better, start with learning about sampling rate, the Nyquist theory, aliasing, artifacts, digital filters and clock jitter. Then you will better understand oversampling and upsampling. I learned quite a bit when I built my dual mono, discrete balanced output DAC.

Thierry Heeb is a founder of the Swiss firm Anagram Technologies. They develop and manufacture advanced high performance audio signal processing solutions found in numerous CD players and DACs. Heeb explains "Oversampling is an upsampling process where the ratio between output sampling frequency and input sampling frequency is an integer larger than 1. Upsampling is any kind of transformation providing an output sampling frequency that is higher than the input sampling frequency and not necessarily a ratio."

"The difference [between oversampling and upsampling] is, to my opinion, more related to the clocking and jitter problem as well as to the statistical distribution of errors or artifacts."

A real simple explanation is by upsampling or oversampling, you keep aliasing frequencies from entering the baseband and thereby distorting the sound. Filters become simpler with gentler slopes.

Most products we can afford to buy are built to a price point. As always, a well implemented design will sound better than one that is not. I've had DAC's with switchable upsampling that were system dependent to whether they sounded good or not. My Twisted Pear Buffalo III DAC with ESS Sabre DAC chips has switchable oversampling and it sounds better with it on than off. So when I hear someone say oversampling or upsampling sucks, I think they haven't listened to enough DAC's yet.

marvda1 · December 2014

in a dac it's my belief that the analog output section is more important than the dac chipset used.

SCompRacer · December 2014

Unfortunately, everything is important.

Input boards, power supplies, etc. DAC chips can make a difference depending on input (SPDIF or I2S) and whether they are voltage or current output. For instance, the ESS Sabre DAC decodes SPDIF differently than other DAC chips. SPDIF has data and clock combined and the DAC chip must sort it out. ESS Sabre does not rely entirely on the embedded clock and their patented method can result in better sound quality decoding SPDIF. Other DAC chips may respond significantly better to I2S input over SPDIF input. I2S is the serial communication used in a CD player where clock and data are separate.

Some folks think the ESS Sabre DAC's sound best with current output than voltage output. If current output, you need a good I/V stage to go back to voltage output.

muncybob wrote: »

If a unit is described as "uses twin Wolfson WM8740 DAC chips" what does this tell me?

Sorry, I went off on a tangent and didn't address your other question.

Any additional terms, like dual differential or dual mono? Dual mono means one DAC chip per channel. I have 8 channels in each of my DAC chips combined for each channel. One DAC chip per channel allows for the best possible SNR (Signal to Noise Ratio) and dynamic range with no timing shifts between channels that is possible with a shared DAC chip. Basically, imaging and channel separation are better. I won't say it's twice as good as the single chip DAC I first built (same power supplies and output board), but the sound quality was well worth the added expense.

Dual differential means running two identical DAC chips in opposite polarity then combined later to lower noise and distortion. IIRC the latest OPPO 105 has two DAC chips but one is for the headphone/stereo output, one for multichannel output.

tonyb · December 2014

muncybob wrote: »

I'm still pondering a purchase of a cd player. Seen comments about players with good and even great dac's. I've also seen comments that lead me to believe that the transport mechanism is possibly just as important as the internal dac. If a unit is described as "uses twin Wolfson WM8740 DAC chips" what does this tell me? I've read enough to know Wolfson is a respected name, but is this particular chip one of their better ones? Is the dac in an Oppo 83 any better than the one in an Azur 740c since the Oppo is newer.I haver also read people saying they were not fans of upsampling and others say it makes a big difference..I'm so confused!

When it comes to cdp's, don't lose sleep over dac chips or make that a deciding factor. A well built unit will sound better overall than a cheap unit with the latest dac chip.

Consumer grade cdp's.....look at Marantz, Cambridge, Pioneer elite. Better....look at Musical fidelity, Cary, and a cast of hundreds more. Depends on what the budget is.

BTW....don't lose any sleep over the whole upsampling thing either as Rich previously explained. Too many variables goes into what makes it bad or good.

muncybob · December 2014

OK, now I have enough understanding to be dangerous as the saying goes. An older Cambridge unit that I have my eye on has dual dac's but I notice one of their newer models has a single dac. If a company decides dual is the way to go why would they make a model with single? Price point?

I think our budget will be in the sub $500 range, considering a Denon 3910 and a Cambridge 740c. As much as having sacd available is appealing to us it seems a dedicated cd player rather than a combo cd-dvd would probably be a better sounding unit and have a better transport????

muncybob · December 2014

Another possibly stupid question...what if I used my current Pioneer DV-563A and a Cambridge Audio DAC Magic? Will this supply me with good analog and sacd? I know the Pioneer is fairly low level but would it be sufficient as a transport?

tonyb · December 2014

As a transport ?? Maybe....maybe not, but differences in transports used these days vary little....audible wise. That may be a different story on cheaper consumer grade products though.

tonyb · December 2014

Not everyone is into streaming Skipper. Actually....some former high priced quality cdp's can be had fairly cheaply these days.

Once you add a dac and additional cables, your at the price point anyway of a decent cdp. Whats left is the convenience factor that comes with streaming.....which btw is off the charts.

[Deleted User] · December 2014

Now you are talking my language!
With giving away a family secret, what should I keep my eye out for.
I think I know some heavy hitters but...

tonyb wrote: »

Not everyone is into streaming Skipper. Actually....some former high priced quality cdp's can be had fairly cheaply these days.

Once you add a dac and additional cables, your at the price point anyway of a decent cdp. Whats left is the convenience factor that comes with streaming.....which btw is off the charts.

tonyb · December 2014

Probably already mentioned Red, really depends on what you want to spend. Musical fidelity cdp's are always highly recommended as is anything from Cary. Music Hall makes a good cdp as does Cambridge. Older OPPO's....Marantz's higher tier players, all good. Pioneer elites even....dirt cheap these days. The older Pioneer elite universal players were stellar cdp's. the AVI 59 and 79. Both can be had under 150 bucks.

Personally though, if I were to stick with a cdp, I'd hunt up a Cary 303, or a Musical fidelity.

[Deleted User] · December 2014

Thanks for the recommendation Tony. I bought an old Oppo just to get in the game.
I'll keep my eyes open. Back to the zeros and ones...

SCompRacer · December 2014

muncybob wrote: »

OK, now I have enough understanding to be dangerous as the saying goes. An older Cambridge unit that I have my eye on has dual dac's but I notice one of their newer models has a single dac. If a company decides dual is the way to go why would they make a model with single? Price point?

Price point is very possible. All depends on the goals and features of the design. Most DAC chips decode raw DSD (SACD) but to save cost they don't include it in the features. Most DAC's don't allow access to any or all the settings that may fine tune for the input source selected.

Just an example, this image from the HiFiDuino Intro site. These are the settings available (left column, FirFilter through Notch) in an ESS Sabre 9018 DAC chip. This is part of the software that allows me 100% control of all options available in my DAC. Some settings work better for DSD, some for SPDIF, some for I2S. The software has the ability to save specific best settings for each input so I don't have to mess with them.

lcde8a1a8e7a4bab.jpg?w=595

The 3910 is a great player as is. It was also mildly and heavily modded, including tube output. I modded mine to export I2S (CD) and DSD (SACD) to my DAC. Some folks still bring hard media to music meets so I have the ability to play anything through my DAC.

tonyb · December 2014

rednedtugent wrote: »

Thanks for the recommendation Tony. I bought an old Oppo just to get in the game.
I'll keep my eyes open. Back to the zeros and ones...

Nothing wrong with that Red, but in case you don't get your sack blown back by the Oppo...

http://app.audiogon.com/listings/cd-sacd-players-rega-planet-2000-cd-player-2014-11-29-digital-77632-orange-tx

muncybob · December 2014

"Server based music is the wave of the future due to convenience, and it sounds better to boot. "

Are we talking about physical media ripped to a computer? Doesn't the quality of the computer transport that was used to rip the physical media come into play?
When streaming is mentioned are we talking about wireless networking?

Man, things were so much simpler back in the days of reel to reel and "record players".

muncybob · December 2014

Tony, I've been looking at that Rega but I cam across a review that said while it was a decent player it lacked deep bass, whatever that is ):
Been looking at 2 Denon 3910, price difference of $150 between them with the cheaper having some cosmetic blemishes that I can live with but would rather not and the other says "converted it from stock 5.1 to a dual mono stereo. "

BlueFox · December 2014

muncybob wrote: »

I think our budget will be in the sub $500 range, considering a Denon 3910 and a Cambridge 740c.

The Cambridge 740C has gotten great press, and mentioned in the same breath being as good as $5k CDPs. I do not have it, but am very happy with Cambridge preamp and amps.

skrol · December 2014

I recently picked up a Sony CDP-650esd from the mid-80's. It uses two BurrBrown PCM53JP-VK which are very dated and even in the day, this deck was meant to be used with the external DAS-702ES outboard d/a converter. Even still, this unit sounds amazingly good because everything else is over built (http://www.thevintageknob.org/sony-CDP-552ESD.html ).

muncybob · December 2014

Now I'm considering the Cambridge Audio Azur DacMagic DAC with my existing Pioneer for kicks. Has the same Wolfons as the 740C(2 per channel) and has a small footprint and a lot less $$ than the cd players on my short list. If that makes the grade I guess I'll then be looking at learning all about computer based music.

tonyb · December 2014

Keep in mind Bob, when looking at reviews of anything, be it professional or user reviews, you have to take it all with a grain of salt. Look for commonality in reviews to get a better picture. You'll always read good or bad reviews for any given product.

Cambridge makes solid products, the dacmagic is a good place to start getting your feet wet in computer music.

EndersShadow · December 2014

muncybob wrote: »

Now I'm considering the Cambridge Audio Azur DacMagic DAC with my existing Pioneer for kicks. Has the same Wolfons as the 740C(2 per channel) and has a small footprint and a lot less $$ than the cd players on my short list. If that makes the grade I guess I'll then be looking at learning all about computer based music.

Bob:

I ran throught a LOT of DAC's in my setup: Internal DAC on Sunfire TGP-II, Meridian Explorer (DAC & Headphone amp), Audio GD NFB-5 (Headphone amp/dac and pre), and the FIRST TIME I play a DacMagic which my buddy brought over to play with, I decided THAT was the DAC for me.

I bought one and have been using it ever since. For me its one of the better DAC's under 500 you can find. Now I have the older just DacMagic, not the Plus or the 100 and I love it. I've seen them go from between 150 - 350, so if you can be patient I am sure you can snag one. Couple sites to checkout would be here, AudioGon, USAudioMart, eBay and Head-fi.org.

I paired mine with a BlackCat Veloce Coaxial cable and basically have the same setup Phil ( @pearsall001‌) had and I could'nt be happier. For now its the DAC that blows back my sack......

I'd give it a go as you can use the USB input (for your computer) the coaxial OR optical input (for a CD player with coaxial or some other transport) and be good. You can even play with the different inputs to see if you prefer one over the other.

Also as its got multiple inputs you can connect a LOT of diff devices to it to see how it sounds.

Tbone289 · December 2014

muncybob wrote: »

Doesn't the quality of the computer transport that was used to rip the physical media come into play?

No, not if the rip is verified as a bit-accurate copy of the original.

muncybob · December 2014

Anybody have any experience with the Parasound Zdac? I ask since I have a Parasound amp for my 2 channel rig. One can be had for $299 new.

muncybob · December 2014

Yet another question...to stream from my PC wireless network I need something between the PC and the DAC, but it's not something as simple as a USB dongle like on our TV?

tonyb · December 2014

http://chicago.craigslist.org/chc/ele/4805173462.html

Here's one for 250 bones, you'd be hard pressed to find a better dac for this price.

Depending on the dac, yes...a usb is that simple.

muncybob · December 2014

That's tempting Tony, but I hesitate to buy off CL if I can't pick it up in person. I was "sold" on the Dacmagic until reading about the Zdac...same price range and 2 year warranty. I'm sure either would do me fine.

Streaming really appeals to me but initially I need to do it on the cheap as I want to get my TT back into the loop. So, if you can use a dongle with a PC why the need for something more elaborate/expensive? I guess I need an education in the digital world...which I am slowly getting here.

I an looking forward to this new audio adventure, haven't been this excited about my rig since I bought my 2B's years ago!

tonyb · December 2014

Because like a TT, everything matters to some degree even in digital.

Why would you need a better cart....heavier platter, better arm ? Why not use the cheapest phono stage you can find ? Think any of that matters on the sound your TT will produce ?

You don't need to be too elaborate....but a dac at 250 bucks is hardly so.

muncybob · December 2014

Yea, I kinda figured that would be the reasoning. If I did not have plans to have my Shure cart retipped it really would not matter. So, initially can you place a dongle in the Dacmagic and stream from a PC? Demonstrating the convenience of streaming to the Mrs may help loosen up the purse strings a bit. It was hearing the Oppo thru the amp/preamp set up that actually got her to agree on the new cd player or DAC concept. Trying to convince somebody that is totally deaf in one ear to spend $$ on audio equipment is no easy task.

tonyb · December 2014

I hear ya Bob, we all have that problem to some degree. Given your wife's hearing problems and the fact that the WAF needs to be high on the priority list, Sonos would be the way to go for you. Not a wife on the planet who doesn't love the thing. Plus you can use the analog outs on the Sonos until you have a dac to insert into the mix or just use the dac you already have in a receiver or anything else with a digital input.

Most wives are....electronically challenged, to put it in a PC way. The Sonos will make them happy to use it, seriously. After you start using one, there are ways to make it better as time goes on and your wallet allows.

You can use a USB plug and go directly into most any dac, if your computer is in the same room or your running a laptop....to answer your question.

muncybob · December 2014

So, can I expect better audio quality from a Sonos as compared the the Cambridge BT100 into a DAC?

msg · December 2014

good question, and furthermore, are you planning to use the CBT100 into a non Cambridge DAC? I was just looking at these, myself, and couldn't help but notice the "any supported Cambridge product" qualifier?

What makes a good dac or transport?

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