[They_call_me_Roto]

In the past couple years I've seen a few posts where people made the claim that current day AVRs will digitize any input signal that comes into the unit via an analog input for processing.

Is this true? If it is true, can anyone provide some solid evidence to support this claim?

Reason I ask is that I have a late model Marantz AVR and an Oppo 105. When I am listening to music from any source (CD, thumb drive) in any format (wav, MP3, flac) the sound is very different if I let the receiver convert the digital to analog versus if I let the Oppo convert the digital and feed that into the receiver over RCA cables. If the receiver is digitizing the analog signal then running it through it's DSP and amplifying the signal, I would expect the music to sound exactly the same no matter how I had the digital converted to analog. But when I let the Oppo do the D-A conversion the music sounds very different which makes me think that the ARV is only amplifying the analog input signal and passing it through to the speakers.

 

[millst]

Yes, they pretty much all do. That's how we get nice things like adjustable crossover points. That processing is done in the digital domain. It's not really feasible to do everything in analog.

Take a look at your manual. There is likely a mode that eliminates the digital conversion, but you'll lose any benefits that provides e.g. room correction. They are often labeled direct, pure, reference, etc.

As far as why things sound different, maybe because your paths looks like:

D->A
D->A->D->A

What the AVR is starting with in the final D->A stage is different because it's already gone through an A->D conversion.

Another point, the Oppo may not be outputting the exact same thing from its analog and digital inputs. The Oppo is probably doing some bass management before doing its D->A, which might then be reprocessed by your AVR.

Finally, the different paths be different in overall volume if you'd didn't level match everything. Even .5dB can make things sound quite different.

-tm

 

[weaselfest]

It depends on what model Marantz you have and what sound field mode is engaged with the Oppo analog inputs. If I remember correctly, some Marantz models claim to offer a direct signal path that won't involve any additional digital processing.