Which Processor?

I see that everybody has their opinion what what is the best processor. Though, nobody really sat down and tried to answer the OPs question.

The Marantz is an economical giant corporation that has large teams of R&D. It also has a very large retail network and sells a lot of units. This means that the cost of the individual units are lower for what you are getting. The Marantz has a fully discrete analog section. They may even be fully balanced/differential. There’s definitely enough elements on each of their analog channels to have two individual op amp circuits for differential/balanced (as seen in below picture). I know hernanbob indicates the Marantz will sound soft/boring. This may have been true with the older generation (8801), but Marantz has re-designed their HDAM circuits to give you more slew rate (and therefore more detail/snap).

http://www.avgearshop.com/media/productImages/Marantz/av8802-current-feedback-sl_420.jpg

The Krell is a smaller company and has a very small retail network (in comparison to Mrantz). These economics mean that Krell has to charge more for their units to recoup R&D. This is a basic economic rule for all audio companies. The Krell Foundation may sound very good, as there are tons of very positive feedback. Based on the cost of the Foundation vs their fully discrete S-1200, and the fact the Krell doesn’t even mention "discrete" on the Foundation page (something they specifically make clear on the S-1200/707 pages), I think the Foundation uses only monolithic op amps. I think there’s a good enough power supply capacitance on the Foundation, which will be really good for bass/midbass on the op amps. I don’t know that they use their discrete power regulation (like S-1200/707). It’s really difficult to see, but they may be using the common LM78xx/LM79xx monolithic regulators. Has anyone opened up a Foundation to see? I do know that Krell normally has excellent power supply design in that they do have a shared transformer, but they have completely independent and isolated power supply sections (diode/rectifier, capacitor, regulator). I have never seen them cascade power supply sections like I have seen on other equipment (like feed the 17V power supply into the 5V power supply).

http://www.audiolab.com/v/vspfiles/photos/KREFOUNDATION-3.jpg

Both units support 4K and a variety of features, such as room correction. Marantz may have more input/output features (don’t know if this is important). The Foundation has excellent user feedback, but the Marantz also has positive reviews. In this case, I might actually lean towards the Marantz because of the discrete/balanced audio stages. The Marantz equipment has generally been very musical and nice/natural to listen to.

Please note that I have not heard either unit. Unless somebody has sat down and listened to BOTH of these units, I don’t know how accurate I would take someone’s assumption that "Krell is better than Marantz" (or vice-versa). As far as if the Krell is worth twice as much as the Marantz, I would say not. It may be worth a little more if someone has compared these two side-by-side and determined Krell sounded better, but the Krell equipment definitely reaches into the realm of diminishing returns (i.e. you will pay a lot more for a little bit of sound quality improvement).

@erik_squires - totally understand. Just chasing after the fastest slew rate is not a good idea (and I know you can get lightning fast op amps for cheap - they are all over the place). Actually, in my extensive R&D with DAC circuits, I have found that 20V/us slew rate is about the perfect slew for audio. A faster slew rate will actually translate waveforms to be faster than they should (i.e. you’ll see a push in the upper mids/highs). However, when the slew rate drops below 20V/us (such as 12V/us of the MUSES01 op amp), the sound will become warmer/fuller but it can also be described as slower/boring.

I was just trying to illustrate that Marantz has made a design change in their HDAM circuits from the older generations and I also read that slew rate was part of that.