AV Receiver Reviews

Really, with the environmental lecture at the beginning? Other than that, a well written review! As usual.

given the comments at the beginning of the review, the measurements are incomplete.

There should have also been be a comparison of power draw to a unit (which can be left unnamed) with Class AB amplification of similar output power.

I suspect, as apparently does the author, that the ICEpower modules will be more energy efficient than standard commodity AB amps. But without data, that's just conjecture. Even the fact that in your tests the Rotel is able to maintain full output power into the 5 and 7 channel ACD tests - a VERY impressive performance! - doesn't necessarily speak to energy efficiency. Rather, it could be the result of a very very good power supply, or conversely of current limiting to game the specs.

For that matter, a measurement of power draw at idle and at 1/8 rated power would be a good standard metric to add to the measurement routine. Energy efficiency is a useful differentiating factor that is directly relevant to consumers' bottom lines.

Another thing that should be added, especially as more Class D AVR's come on stream, is a test into a simulated load, such as the one designed by Ken Kantor and tweaked by JA for Stereophile. Class D amps usually have output filters that interact with the speakers up top, creating variances in the top-end frequency response. It would be good to see which designs are optimized for certain loads, and which ones are designed with output filters that vary the source impedance less.

Lastly, it is unfortunate that nobody has yet combined good Class D amps with a modern room correction system. The Rotel's room correction system is primitive, so to me it's a very poor value compared to something like an Anthem MRX box. Somebody make me an AVR with energy efficient amps and a real room-correction system such as ARC or Trinnov!

I recently bought the Rotel RSP-1572 and have found the software and firmware to be suffiiently buggy so as to impinge on the enjoyment of ownership. That product never should have been released. It sounds like the imaging issues you describe are less about Class D and more about clocking errors. The flagship processor suffers from numerous clocking issues - sounds great until it doesn't, often needs a reboot. It sounds like this product is another case of shoddy Rotel engineering being rushed out the door. If they spent a little more time or hired a couple more people they could have put out some great products. If I had the money to buy something else I totally would and I'm guessing that this AVR will be a similarly in enjoyable product to own, despite it's great potential.

Oh, I like the environmental discussion.

Edit: one way to test if the problem is with the Class D amplification or bad/buggy digital audio conversion would be to let the Oppo decode the surround and send it out as audio into the Rotel.

I was considering an upgrade to my RSX-1550.

I originally bought that over the RSX-1560 exactly because the '50s AB amp stage sounded so much better than the '60s Class D.

Is there going to be an RSX-1552 ?

I would love to love this Rotel receiver, but I just can't.
It is not competitive, in all aspects, even sound quality.
...And certainly not in price.

And Rotel should go back to class AB amps.

Thank you for listening.