Even if you're not in the market for a new receiver, purely as a fan of AV tech, you owe it to yourself to find a Cambridge Azur 751R receiver and - if you can lift this meaty beast without herniating a disc - take a quick gander at its hindquarters. Marvel at what seems like an anachronism in this age of downright desolate receiver back panels: the 751R is so densely packed with ins and outs, control ports, switches, and even a massive (but whisper-quiet) cooling fan that there's hardly a square inch of anodized black metal to be found between its radio antenna connections and its AC power port.
The back of the 751R is so densely packed with connectivity, in fact, that it may be a few beats before you notice the presence of another anachronistic inclusion and one notable omission when contrasted with the bulk of today's big-box AV receiver offerings: this thing has S-video inputs ... and no Ethernet port! These are merely the first and most obvious clues that the Azur 751R isn't cut from the same cookie-cutter mold as the bulk of its competition - the first inkling that Cambridge is aiming for a different sort of consumer, with a different sort of taste, who is drawn more to pure audio performance than streaming Internet features and smartphone app control.
The second inkling comes by way of a glance through the beautifully milled ventilation slots on the top of the receiver to the colossal custom toroidal transformer that pretty much hogs the entire front left quadrant of the interior of the 751R, as well as the thick heat sink and fan mechanism that runs down its center from front to back. Those two elements also contribute to much of the Azur 751R's 40-pound heft, despite its relatively modest size.
The third big clue that this definitely isn't your typical mass-market family room receiver requires a bit of digging into the manual or spec sheet, where you'll discover that the 751R boasts Anagram Technologies Adaptive Time Filtering, which upsamples incoming digital audio signals and applies jitter suppression before passing the results along to the receiver's DACs.
Oh, and that USB port you overlooked on the back because either you were overwhelmed by all the other connections or you assumed that, given the lack of an Ethernet port, it was probably just reserved for firmware updates? Yeah, that's actually an asynchronous audio input, with support for both USB Audio Class 1.0 and 2.0, which makes the Azur 751R not only a beast of an AV receiver, but also a high-quality 24-bit/192kHz DAC for Mac, Windows XP, Vista, 7 and (if you sacrifice three chickens under the light of a harvest moon while vowing to deliver your firstborn child into the arms of Cthulhu) Windows 8 machines. That isn't a knock against Cambridge Audio, by the way; rather, it's a knock against Microsoft, which decided that native drivers for USB Audio Class 2.0 (not to be confused with USB 2.0, by the way; one is an audio standard, the other is a port standard) wasn't worth the effort in recent operating systems. Cambridge goes a long way toward rectifying that oversight by offering its own USB Audio 2.0 drivers, which can be installed to Windows 8 in Windows 7 compatibility mode, along with a handy guide covering all the ups and downs, ins and outs of high-fidelity computer audio playback. Cambridge has also assured me that in the coming months they will have a new USB 2.0 driver that will work natively with Windows 8 and eliminate all that nonsense.
Another interesting (although certainly not unwelcome) throwback is the Azur 751R's positively retro-tastic graphical onscreen interface, which lacks all of the transparent overlays and pastel colors of most modern receivers, but features a nice, intuitive layout that provides logical access to the unit's wealth of audio, video, and input options.
Given the density of the back panel, hooking up the Azur 751R is certainly a little more time-consuming than I've become accustomed to as of late. Since I did all of my testing in my secondary media room, not the main home theater, I only needed three of its five HDMI inputs for my OPPO BDP-93 Blu-ray player, Dish Network Joey Whole-Home DVR Client, and Xbox 360. I used five of its seven five-way speaker binding posts for the Monitor Audio MASS speaker system in that room at the moment; the other two can be configured as either rear or height speakers (neither of which I used). The binding posts are a little chintzy for a receiver at this price level, but are nicely color-coded. Oddly, they're plugged from the back, so if you want to use banana-plug-terminated speaker cables (I do), you'll find yourself digging those little plugs out for the better part of a minute, but that's not a major complaint. Finally, I used just one of the two main subwoofer outputs. I ignored the 751R's generous three IR output ports, preferring to use my Control4 system for such tasks, but I did take advantage of one of its two DC trigger outputs to handle power commands for the Monitor Audio MASS subwoofer.
The back panel's small, silk-screened labeling also made hookup a bit of a struggle for these old eyes. As such, I initially plugged my subwoofer into the Zone 2 sub out, which is situated right above the binding posts, whereas the actual main zone subwoofer pre-outs are located near the upper right hand cover of the back panel. Needless to say, that didn't work, a fact that became apparent as soon as I tried to run the Audyssey 2EQ setup program. No, that's not a typo. This $2,999 receiver - with all its incredible Class AB amplification, its awesome power supply, its high-resolution up-sampling and 192/24 DAC support - includes the sort of cheap, ineffectual room correction that most manufacturers have abandoned even on their most budget-oriented models. Not only is 2EQ by far the lowest-resolution room correction system that Audyssey offers, it also features absolutely no correction for the subwoofer, which is actually the piece of equipment that most requires room correction. It's also far less effective at getting even the essential speaker settings correct. After running 2EQ in my system, moving the included microphone to three locations and letting it run its calculations, the only thing it managed to get correct was the number of speakers in my system (after I plugged the sub into the correct output, that is). Distances were drastically off. Levels were completely out of whack. And, worst of all, it miscalculated the appropriate crossover point between the MASS satellites and sub to an astonishing degree. Monitor Audio recommends an 80Hz crossover for the MASS system, and although it's technically kinda-sorta capable of that, a 90- to 100Hz crossover point results in a much more seamless blend. Audyssey 2EQ, on the other hand, seemed to think that the front channels were cable of reaching down to 60Hz and the surrounds (same speakers, mind you) to an absolutely subterranean 40Hz. If this were a receiver marketed toward a newbie general audience, this would be unforgiveable. Oddly, though, it ends up not really mattering much, because I imagine anyone in the market for a receiver of this caliber has every intention of pulling out the SPL meter and measuring tape and adjusting everything manually. I hope so, anyway ... because setting basic speaker parameters isn't the only area where 2EQ does more harm than good (more on this in a moment).
Thankfully, a receiver like the Cambridge Audio Azur 751R, when paired with a good set of speakers, doesn't need room correction, except for perhaps a bit at the bottom end. With my regular Anthem MRX 700 receiver, I'm in the habit of only applying Anthem Room Correction on the bottom 200Hz or so of the signal. Without that option in the Cambridge receiver, I spent the better part of an hour repositioning the Monitor Audio MASS subwoofer to combat a few nasty nodes. Incidentally, for a day or two, I also played around with a Sunfire ATMOS XT Series Subwoofer in the system, making use of its integrated room correction system and microphone to achieve much the same effect so, if you're in the market for the Cambridge receiver and haven't decided on a sub, the Sunfire or something like it may be a good option, especially if you don't have a lot of flexibility in terms of sub placement.
Read about the performance of the Cambridge Audio Azur 751R AV receiver on Page 2.