Again, I lowered the volume to get there. I don't know what the term "rated" means other than, "we had to reduce it to this level to get the least distortion to publish." It is not how a balanced output is used.
You know perfectly well what rated output is, Amir. If an amplifier is rated at 100W and you test it at 150W and it overheats and shuts down, does that mean you savage the device in your review?
I'm not excusing the Marantz at all. The few 'specifications' they did provide are incomplete and certainly don't aspire to the state-of-the-art.
That said, it bettered its THD+N and dynamic range specifications, even when tested at 'your' levels, something you haven't acknowledged.
All I'm pointing out is that it is not fair to compare the performance of a $100 plastic box headphone amp or DAC with that of a 16+ channel AVR. I just think you're unfairly mixing apples and oranges. It's not a "reference quality DAC" but a "reference quality AVR".
Exactly true. It's easy to make a quiet headphone amplifier or a datasheet application note 2ch DAC-in-a-box. Let's not pretend it isn't. This Marantz thing has wall to wall DSPs, rows of D/A converters (see the pic below), an incredibly sophisticated switching and routing matrix for digital audio, digital video and analog as well.
It's a rat's nest of design, with little care given to shielding or separation. The price you pay for that is obvious without even needing to plug in a USD$28,000 AP. More noise, THD and likely an anemic output stage.
Here for comparison is a
rated set of specifications for a 1988 Yamaha CX-1000 preamplifier with inbuilt 18bit dual D/As. Back then it cost AU$2399. I sold a lot of these, along with big MX-xxxx series power amps.
To obtain performance like that and residual less than 1.5uV, the attention to detail was phenomenal for such a reasonably priced preamplifier. This pic from the 'net shows the internal sectional cover plates removed.
Phono MM/MC stage on the right in separate enclosure w/power supply.
Digital D/A centre with own transformer.
Control centre front section
Analogue line stage front
From underneath:
Buffering on every input
Analog bypassable tone stage PCB front etc