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NAD C375BEE MDC DAC and volume levels versus analog inputs

post #1 of 5
Thread Starter 
Hi All,

I have an NAD C375BEE and recently had a mishap w/ liquid poured into the unit (well, I had to send it in for repair and that that was the response from NAD - I didn't witness the accident, but neither did my daughter :-)

Anyway, while I was sending it in for repair, I decided to add the MDC DAC module. When it came back, I was very surprised by the difference in volume level between the DAC and the corresponding analog input.

I have recently added a Denon DNP-720AE (network audio player) that I connect both via TOSLINK and analog RCA interconnects. With DAC input, the volume becomes uncomfortably loud around the 11 o'clock position of the dial. With the analog inputs, I can turn the unit all the way to max volume and it's loud, but way less so than the DAC input. And, frankly, the sound is, well, thinner / less full.

I repeated a similar experiment with a Denon DBP-1611UD (2-channel analog output).

Thinking that the repair had not been successful, I returned the 375 to my local dealer, who similarly connected an NAD CD player (both via TOSLINK and analog).

To my embarrassment, the volume levels were nearly matched (although the sound quality was night/day different - the MDC DAC output was horrible - but that's another topic). The dealer explained that in the time required for me to drive to the dealer, the 375's capacitors has drained and, voila, the system was reset and all is well - "...happens all the time at our store."

Ah...OK...? So, I shrugged my shoulders and took the unit home and plugged everything back in and, no surprise, same result - my sources had wildly different volume levels between the MDC DAC and the corresponding analog inputs, although turned up to, say, 2 o'clock, the sound was fine.

What gives here, I am stumped? This is the first time I've connected the Denon sources to this int. amp; is it possible that the analog out levels from the Denon network and BD players are really that low or is something else not right? I tried switching cables and moving to different input jacks - not exhaustively, but a couple of them, with the same result.

Thanks, in advance...
post #2 of 5
Quote:
Originally Posted by Krutsch View Post

Hi All,

I have an NAD C375BEE and recently had a mishap w/ liquid poured into the unit (well, I had to send it in for repair and that that was the response from NAD - I didn't witness the accident, but neither did my daughter :-)

Anyway, while I was sending it in for repair, I decided to add the MDC DAC module. When it came back, I was very surprised by the difference in volume level between the DAC and the corresponding analog input.

I have recently added a Denon DNP-720AE (network audio player) that I connect both via TOSLINK and analog RCA interconnects. With DAC input, the volume becomes uncomfortably loud around the 11 o'clock position of the dial. With the analog inputs, I can turn the unit all the way to max volume and it's loud, but way less so than the DAC input. And, frankly, the sound is, well, thinner / less full.

I repeated a similar experiment with a Denon DBP-1611UD (2-channel analog output).

Thinking that the repair had not been successful, I returned the 375 to my local dealer, who similarly connected an NAD CD player (both via TOSLINK and analog).

To my embarrassment, the volume levels were nearly matched (although the sound quality was night/day different - the MDC DAC output was horrible - but that's another topic). The dealer explained that in the time required for me to drive to the dealer, the 375's capacitors has drained and, voila, the system was reset and all is well - "...happens all the time at our store."

Ah...OK...? So, I shrugged my shoulders and took the unit home and plugged everything back in and, no surprise, same result - my sources had wildly different volume levels between the MDC DAC and the corresponding analog inputs, although turned up to, say, 2 o'clock, the sound was fine.

What gives here, I am stumped? This is the first time I've connected the Denon sources to this int. amp; is it possible that the analog out levels from the Denon network and BD players are really that low or is something else not right? I tried switching cables and moving to different input jacks - not exhaustively, but a couple of them, with the same result.

Thanks, in advance...

The levels associated with digital inputs and outputs are generally always going to be very similar and there is no reason why they wouldn't be identical.. In digital "as loud as it gets" is called full scale or FS, and FS is the same for all digital inputs and outputs.

Not so with analog. There is no rule written in stone that says that an analog output has to be a certain voltage for "as loud as it gets"on any recording, and there is no voltage that is the one and only standard voltage for "as loud as it gets".

As a consequence, what you observe is to be expected.
post #3 of 5
Thread Starter 
Quote:
Originally Posted by arnyk View Post

The levels associated with digital inputs and outputs are generally always going to be very similar and there is no reason why they wouldn't be identical.. In digital "as loud as it gets" is called full scale or FS, and FS is the same for all digital inputs and outputs.

Not so with analog. There is no rule written in stone that says that an analog output has to be a certain voltage for "as loud as it gets"on any recording, and there is no voltage that is the one and only standard voltage for "as loud as it gets".

As a consequence, what you observe is to be expected.

Thanks for the reply, ArnyK. I get all that, but I was really shocked at the difference, going from 11 o'clock on the volume knob to 5 o'clock to hit the same output level seems extreme. I am going to move another source up to the listening room and see if anything changes.
post #4 of 5
Arny is right about digital having a standard for levels, whereas analog does not.

The unwritten rule that I know of is that analog outs are typically 2V rms for 0dBFS, but that is not an actual requirement, just a general industry practice that any manufacturer may follow, or may not follow.

There is one further complicating thing that could be at the heart of your issue:

Does your network audio player have any settings for dynamic range compression? I'm not familiar with that product. But if it does have such settings, try changing them. Same with the universal disc player.

I have seen several products where the analog output levels are affected by the dynamic range compression settings (not just in the expected way of changing the dynamic range on the outputs, but also in that an offset of 10dB or so is added or taken away on top of that).

Edit: The NAD CD player doesn't concern itself with any dynamic range compression, so it's a simpler task for it to have more consistent output levels for the digital and analog outputs.
Edited by beaveav - 9/6/13 at 5:12pm
post #5 of 5
Thread Starter 
Quote:
Originally Posted by beaveav View Post

Arny is right about digital having a standard for levels, whereas analog does not.

The unwritten rule that I know of is that analog outs are typically 2V rms for 0dBFS, but that is not an actual requirement, just a general industry practice that any manufacturer may follow, or may not follow.

There is one further complicating thing that could be at the heart of your issue:

Does your network audio player have any settings for dynamic range compression? I'm not familiar with that product. But if it does have such settings, try changing them. Same with the universal disc player.

I have seen several products where the analog output levels are affected by the dynamic range compression settings (not just in the expected way of changing the dynamic range on the outputs, but also in that an offset of 10dB or so is added or taken away on top of that).

Edit: The NAD CD player doesn't concern itself with any dynamic range compression, so it's a simpler task for it to have more consistent output levels for the digital and analog outputs.

Thanks, beaveav... it never occurred to me to even look for something like that in a 2-channel audio device like the 720AE, but I will go back though the menus and verify. The universal disc player, on the other hand, could certainly have something like that enabled. The Denon BD player has a Pure Direct mode that I enable during playback; one would hope that would disable anything like DRC, but who knows.
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