1. In my experience with two Marantz processors, the AV7005 and AV8801, the answer is "No"
2. Imo, it can be explained by the well known "bias effect", and/or Placebo effect, can also be due to not comparing under the same conditions. When I upgraded a piece of gear, I would naturally dust things off, wipe clean everything and everywhere, picked the best quality recording contents I could think of to try the new toy; and find quiet moment to listen for any "expected" difference. Having done all those things, the gear almost always seem to sound better in the beginning, until reality eventually came back. It's like, after a full car wash, the car woulld to run smoother, definitely quieter too.
3. If you look at all the receivers and processors bench tested at ASR, the receivers actually tested/measured far better than the processors in most cases, though a couple of the processors did came close, within striking distance.
A dedicated processor should theoretically be able to achieve higher SNR due to more space available, better shielding can be done, less heat and electromagnetic interference, and the opportunity to use better parts and wiring technique. Practically speaking, they don't seem to have achieved all of those theoretically achievable things. A possible explanation could be that they don't have the sales volume to support the necessary investments required for the theoretical gains I mentioned, so they ended up basing the product on a mid range to high end receiver, just without the power amp sections, use a much smaller power supply, and add XLR connections and then sell them as preamp/processors as though they are fundamentally different, when in reality they are fundamentally the same. I cannot explain why they tested/measured worse, except perhaps the boutique brand ones don't have the resources that Yamaha, D+M has, so they ended up messing certain important things up; and the Marantz processor did worse than Denon receivers most likely because of their use of HDAMs, to create a preconception in the buyer's mind, such that those buyers/followers/fans would have something to count on, ended up with some expectation bias from the beginning. Unfortunately, in this case, more is not better, HDAM might have (just me educated guess based of things I read) resulted in higher distortions and noises, albeit low enough, that is, below the threshold of audibility.
