[marios_mar]

Hi,

1. Are all digital outs from all CD players of equal quality or of similarly equal quality. i.e. Would a cheapo AIWA mini system with digital out when connected with a great DAC sound to an amp the same as an expensive marantz connected via digital out through the same DAC on the same amp? Would the difference be significant?
2. Do DACs have pots for volume control?

 

[planar]

1. Expensive CD players may have better design in their digital section, which means more information is collected with less jitter. Cheap CD players can not have the same level ofsignal transducting pathway as with expensive CD Players. Threrefore, if expensive CD players' transoport components are well designed, then they should have better, purier digital signal than cheap CD players.

2. Most DAC only process signal, some DACs may have pre-out section which can be used as a pre-amp.

 

[lan]

The power section and transport will affect the quality of the digital out so not all CD players sound the same. It comes down to ones with less jitter and less errors.

Most DACs just have line level outs no volume control.

 

[marios_mar]

ok sure i thought that myself too. But my question is if there is a significant difference between a cheap and an expensive CDP. Is the difference as significant as it is by getting sound output from analog RCAs (using the integrated DACs the CDPs use). Or is the difference smaller and bearable by using an external DAC or even sometimes unnoticable?

 

[bifcake]

Hi Marios,

The answer is yes and no. As stated earlier, the power supply and other components may introduce noise that would interfere with a digital path, thus introducing errors and thereby causing jitter when using an external DAC.

The problem with the digital signaling (SPDIF) is that unlike ethernet or other digital protocols, there is no clocking or error correction built into the SPDIF protocol. So, when a DAC receives a digital signal, the errors are what is referred to as jitter.

However, from what I gather, many of the DAC manufacturers have built some sort of error correction into their DACs. I don't exactly know how they did it without having a checksum on the source side, but they were able to do something to minimize the jitter. So whereas a good digital source is still important, it's no longer a drastic difference between a cheap transport and an expensive transport.

However, it's ALWAYS better to have an error free data stream to begin with, rather than relying on error correction mechanisms.

To conclude, yes, it's better to have a good digital source. It won't be a drastic difference if you use a cheaper source, however, it's hard to quantify the difference. It all depends on how picky you are and your budgetary constraints.

 

[Silver]

If the transport makes no drastic difference, why would ppl pay hundred of bucks solely for a good CD transport?

 

[Canman]

I think the law of diminishing returns for transports kicks in a little higher than a few hundred bucks. There are good transports to be had for not much money but I would have to say it is the same with headphones. HD600's are twice the price of HD580's but the difference is not that large. The average person couldn't tell the difference with a quick listen but for many of us the additional transparency and detail is easily worth the additional money.

A good cheap transport on the used market is any of the Pioneer products with the Stable Platter transport. A lot of the High end manufacturers have used this transport in their players. The Pioneer PD-65 is on audiogon all the time for $250-$350 and has wood panel sides and solid build. It is also a decent sounding standalone player.

In my experience the source is highly underrated and mechanical isolation of a good transport lets the DAC do a better job here. Digital cable selection is also important according to my engineering friend because digital is transmitted at a much higher frequency than that of an analog signal. Therefore in theory the digital cable is more prone to a degradation in signal than an analog interconnect is.

Bifcake, the Wadia transport / DAC separates actually have 2 different connecting digital cables, one for the digital signal and one called Clocklink, which does this checksum you speak of.

 

[bifcake]

Quote:

Originally posted by Canman Bifcake, the Wadia transport / DAC separates actually have 2 different connecting digital cables, one for the digital signal and one called Clocklink, which does this checksum you speak of.

That must be a proprietary architecture to Wadia. So, in order to use that feature, you would have to have matching transport and DAC. I wish every manufacturer would add a clocking mechanism to their transports/DACs and those clocking mechanisms were standard and interchangeable.