Digital vs. Analogue source

[Buckle-meister]

Dear all,

Here are general questions for which I would appreciate knowing the answers, since I am looking to purchase a DVD/SACD player in the near future:

1. Assuming that I use the i-link interconnect from the player to the amp (my amp does support it), will the quality of a PCM CD signal be better, worse, or identical to that obtained by using a coaxial digital interconnect. I suspect that it will be better since the amp gives priority to that input over PCM. I am unaware why this is so though.

2. If the DAC in both the DVD/SACD player and AV amp are identical, then, with regard to CDs, will the music sound 100% identical regardless of whether I use the players DAC by using analogue interconnects, or AV amps DAC by using a digital interconnect?

3. If there is such a big push these days to try to keep a signal in the digital domain as long as possible, then can anyone explain why my AV amp, with its 'Pure Direct' button states in its manual that "...for uncompomising pure audio, Pure Direct allows you to enjoy the highest possible fidelity from audio sources...", yet this is achieved by using ANALOGUE interconnects (whilst the amp shuts down the digital circuitry)?

Thanking you

Robbie

 

[MDS]

1. Assuming that I use the i-link interconnect from the player to the amp (my amp does support it), will the quality of a PCM CD signal be better, worse, or identical to that obtained by using a coaxial digital interconnect. I suspect that it will be better since the amp gives priority to that input over PCM. I am unaware why this is so though.

Identical. Input priority doesn't affect the quality of the signal. It is purely for convenience so you don't have to manually change from analog to digital input. Nearly all receivers nowadays use auto input selection - it's useful in the cases such as 'digital cable' where not all of the channels actually have digital audio. The receiver will automatically choose the digital signal if both analog and digital signals are present and automatically select the analog when no digital signal is present.

2. If the DAC in both the DVD/SACD player and AV amp are identical, then, with regard to CDs, will the music sound 100% identical regardless of whether I use the players DAC by using analogue interconnects, or AV amps DAC by using a digital interconnect?

If they are truly identical, there will be no difference.

3. If there is such a big push these days to try to keep a signal in the digital domain as long as possible, then can anyone explain why my AV amp, with its 'Pure Direct' button states in its manual that "...for uncompomising pure audio, Pure Direct allows you to enjoy the highest possible fidelity from audio sources...", yet this is achieved by using ANALOGUE interconnects (whilst the amp shuts down the digital circuitry)?

That is mostly marketing b.s. although many do think that the pure analog signal will sound the best. The reason there is a push for all things digital is that once you have the signal in digital form, it is easier to maniuplate; eg bass managment is expensive and difficult to do in the analog domain whereas it is relatively simple in the digital domain. Unless the receiver uses a digital switching amplifier, the digital signal must always be converted to analog before amplification. Analog aficionados may argue that such a D/A conversion will audibly alter the signal and so it is better to keep the signal analog all the way - that is why manufacturers provide 'direct' modes - to appeal to those people. I personally don't agree - even the cheapest DACS on the market will be audibly transparent for the vast majority of non golden-eared people.

 

[Buckle-meister]

Thanks for your prompt reply; much appreciated. However, I am still somewhat perplexed by question 1.

I understand that priority itself doesnt affect the signal quality, however, isnt the reciever automatically selecting digital over analogue because it 'believes' this to be a better quality signal source? If this is so, then why automatically select i-link over digital since the quality of PCM should be identical for each?

Is it because the reciever 'believes' that it may recieve DSD signals, and so defaults to i-link over digital for that reason?

Thanks again.

Robbie

 

[MDS]

I suppose you could say that the priority order was chosen because digital is inherently better than analog but I would argue that it has more to do with the relative capabilities of each type of input.

- Analog inputs can only accept analog signals.
- Optical or Coaxial digital inputs can only accept PCM or PCM-based signals like DD or DTS. [Technically they transport s/pdif frames and source devices currently only know how to package raw PCM, DD, or DTS data into s/pdif frames].
- The i-link interface can transport all of the types that optical and coaxial can transport as well as MLP (DVD-Audio) and in some cases DSD (SACD). It has a much higher bandwidth and can deal with the increased bit rate of those formats.

So i-link is the 'most capable' interface and seems to be a logical choice for getting the highest priority. Given that the current focus is towards everything digital from source to sink and simplifying connections with one cable to transport everything, I think that is why the i-link interface has the highest priority.

 

[Buckle-meister]

Dear all

I was going to start a new thread, then remembered about one of my first queries .

From the foregoing, We have an explanation for why an i-link interconnect has priority over other digital and analogue interconnects. However, why does my amp give priority to a coaxial over optical interconnect? They are both digital, but the optical has the advantage of not picking up any interference whereas the coaxial might.

Regards

 

[MDS]

However, why does my amp give priority to a coaxial over optical interconnect? They are both digital, but the optical has the advantage of not picking up any interference whereas the coaxial might.

Regards

You must have a first or second generation receiver. That was the scheme that was used initially - there were only two digital inputs, one coax and one optical, and they couldn't be assigned to any source input like current receivers.

As to why coax was given higher priority than optical, I could only guess. I would assume it was because the marketing types thought it would be easier because the coax cable looks like a regular audio cable with rca connectors and consumers would have them lying around [even though you really want a 75 ohm cable, an old 50 ohm analog cable will work just fine in the vast majority of cases], whereas the optical connection would require the purchase of a new cable.

 

[j_garcia]

Optical may not pick up RFI, but it is also prone to jitter, so there are good and bad to both. I always choose coax whenever possible simply because the connection is much more positive than optical.

 

[Buckle-meister]

You must have a first or second generation receiver.

Erm, I have the Yamaha DSP-Z9

Regards

 

[mfabien]

Erm, I have the Yamaha DSP-Z9

Regards

Would have been nice to have a list of your audio and video equipment listed in your signature.

 

[Buckle-meister]

Would have been nice to have a list of your audio and video equipment listed in your signature.

I didn't want to come across as a poser. Note: Nothing is implied by that. Each to their own.

Regards