I recently became interested in audio components with class D amplification ranging from receivers to amplifiers. I had a pleasing experience with Panasonic's class D receivers, found them to have a warm tube sound while having excellent bass control. I have since purchased an Onkyo TX-LR552 which is different from most other class D driven amplifiers that I have encountered in that it uses a linear power supply in favor of a switching power supply. Pioneer's ICE Power based receivers are the only other receiver I know of that uses a linear power supply. The build quality is excellent as well with the use of extruded aluminum heatsinks for the discrete output devices, and Nichicon 10,000uF caps, it's surprisingly robust.
It sounds neutral as it should. I think Onkyo takes pride in accomplishing total lack of color in any amplification devices they produce. Unlike the Panasonic SA-XR70 I had the Onkyo has a wealth of standard home theater receiver ground features and qualities, such as an adjustable crossover that allows you to set it as low as 60Hz where the Panasonic is limited to 100, 150, and 200Hz if memory serves. Power output is substantial, seemingly not limited by the power supply like many other class D amplifiers that utilize a switching power supply.
Overall the SR-LR552 is quite handy for the task of home theater and it works nicely for stereo as well. As many know, I've become quite the fan of space conservation and the minimalist look. I don't mind large components but I find myself avoiding them where I can just for appearance. I definitely enjoy the "the sound is coming from that" feeling I get just about every time new material is being pumped through either my living room or bedroom systems.
