ADC measurements

[K man]

As far as I can tell @amirm has not been measuring the ADC performance on any of the AVR reviews.

I think this is a bit unfortunate as a lot of people (in particular among regular users) are using the analog ins to plug in a variety of sources.

There is then a common wisdom (among non-regular users) to use Direct when using analog in, to avoid the ADC - DAC route as it degrades performance.

But at the same time I see that most people want to keep using Audyssey, Dynamic EQ, channel upmixing, tone control, etc. also when switching over to an source that happen to be connected through analog.

Now, if the ADC were on par with or even better than the main DAC, this wouldn't be a problem. Then there would be little loss in using analog compared to digital in. However, at least for Denon, this doesn't seem to be the case.

I do believe though that if Amir started measuring the ADC performance it would put pressure on the AVR manufacturers to fix this issue - by putting in an ADC that is at least on par with the main DAC. Essentially solving the old "use Direct when you use analog source" issue.

 

[kiwifi]

What analog sources do you have?

 

[K man]

What analog sources do you have?

CD player, vinyl player, media player, streamer, tape player, ...

 

[LTig]

CD player, vinyl player, media player, streamer, tape player, ...

3 of those are digital so you'd better connect them digital to circumvent an unneeded DA/AD conversion (if the amplifier has sufficient digital inputs).

 

[K man]

3 of those are digital so you'd better connect them digital to circumvent an unneeded DA/AD conversion (if the amplifier has sufficient digital inputs).

I think the whole point of my post is being missed here.

There are devices that are being connected to analog (out of necessity, laziness or lack of knowledge). When doing so people advice "use Direct to avoid degrading the sound".

That conflicts with the fact that people often want to continue using the receiver features also when listening to an analog source.

This conflict, or problem, doesn't exist out of necessity. It exists because the receiver's ADC is inferior to the main DAC. A problem the receiver manufacturers could easily solve, if it was highlighted.

 

[Masza]

Some manufacturers have issues from DAC to output stage as well. I think that should be adressed first.

But I'm not saying measuring ADC performance wouldn't have benefit. While at it, let's check the phono stage too.

 

[Masza]

I would also like too see the impact of DSP (crossovers, room EQ) to the SINAD, THD, jitter, linearity etc. If I recall Denon 3400 limited the max volume setting when Audyssey was on and the noise floor was lot higher when volume was set to that maximum versus Audyssey off.

 

[kiwifi]

I think the whole point of my post is being missed here.

There are devices that are being connected to analog (out of necessity, laziness or lack of knowledge). When doing so people advice "use Direct to avoid degrading the sound".

That conflicts with the fact that people often want to continue using the receiver features also when listening to an analog source.

This conflict, or problem, doesn't exist out of necessity. It exists because the receiver's ADC is inferior to the main DAC. A problem the receiver manufacturers could easily solve, if it was highlighted.

ASAIK manufacturers do publish specs for frequency response and distortion for an AVR's analog inputs.

I doubt that any "degradation" of the analog source would be audible and would pale in comparison to the advantage of having room correction active. With today's quality room correction solutions, the advice to use Direct Mode is just plain wrong.

 

[GalZohar]

I would also like too see the impact of DSP (crossovers, room EQ) to the SINAD, THD, jitter, linearity etc. If I recall Denon 3400 limited the max volume setting when Audyssey was on and the noise floor was lot higher when volume was set to that maximum versus Audyssey off.

That would definitely be important, because if Denon wins on SINAD with pure direct but loses with room correction enabled, then for most people it loses. I tried to search if/where this was discussed in the past but only came up with this thread.