I can't believe people are still *&^%$#@ about this Denon vs Yamaha thing!!! Before this thing gets locked (hope not..), may be I am going to say something too (or just one more time, as I might have said something similar before) based mainly on my own observations.
First of all, like ADTG, HD etc., for sound quality, my belief is that the likes of the midrange Y,D,M's comparable models are all good enough to pass an apples to apples double blind test in direct/straight/pure direct sort of modes when no REQ and/or DSPs are in effect.
In terms of running "warmer" or "hotter", while it certainly depends on each individual case to some extent depending on placement (space for natural vent/cooling), room temperature, and how the unit is used, that is, "how loud", types of contents listen to etc., I do have the following observations that I believe are more on the objective side of the equation:
- Yamaha's enclosures are relative larger (physical dimensions and number of amp channels)
- Denon/Marantz from X3600H and up models have better quality heat sinks vs Yamaha's stamp metal style ones
- Yamaha's heatsinks, look less robust (stamp metal types) but it looks like they have more surface area for heat dissipation so they likely would dissipate heat more effectively.
- Yamaha's power amp section has a better layout, comparable to the much more expensive Denon and Marantz flag ship models.
On the subjective side, clearly Yamaha's will likely run noticeable cooler based on the overwhelming praise from forum/users feedbacks.
There is still at least one unknown that happens to be an important factor, that is, the power amp design. On that, based on class AB design, it is well know that "bias" applied do have a narrow range, but also has a lot of influence on how warm the amp would run. My educated guess is that D+M's likely use higher bias, to achieve better distortions numbers/perceived sound quality, but that's just my guess as I have no way of comparing their bias currents even after reading some of their service manuals. Part of the basis of my guess is, both are of the class AB design that is well defined and to a large extent, the circuitry are becoming very similar, such as the use of push pull, Darlington output stages etc., so the remaining unknown that could contribute to heat load is the amount of "bias".
For those interested in more in depth explanation of higher bias vs lower, here's a link:
Pass LabsLeaving Class A - Pass Labs
Regardless, D+M's better measurements will almost certainly not translated into any audible benefits. The benefits of higher bias that N.Pass talked about, imo while true on paper, may not matter all that much for real world use.
