Denon 4520 (2012–2013)

The Denon 4520 - sold as the AVR-4520CI in North America - was Denon's flagship AV receiver for the 2012-2013 model years. It was a heavyweight nine-channel design rated at 150 watts per channel into 8 ohms with 0.05% THD. Suggested retail price at launch was around $2,199, though some reviews cited $1,999.

On the audio side, the 4520 used Burr-Brown PCM1795 DACs on all channels and included Audyssey MultEQ XT32 room correction. Sound & Vision (November 2012, p.64) praised it for "musical and transparent" sound quality. It also had built-in Wi-Fi, Bluetooth, and AirPlay for network streaming, plus Denon Link HD for use with compatible Denon Blu-ray players. An Analog Devices ADV8005 chip handled video processing, with 4K/60Hz passthrough and upscaling for all sources.

Connectivity was generous. You got three HDMI outputs and either eight or nine HDMI inputs depending on the source. The discrepancy likely comes from counting the front-panel jacks differently. Beyond HDMI there were component and composite video inputs, optical and coaxial digital audio inputs, a phono input for MM cartridges, and two sets of 7.1-channel preamp outputs. The unit runs hot and needs adequate ventilation - both reviews and owner forums say so. HDMI board failures have been reported after three to five years of use, and Denon no longer stocks replacement parts for this generation.

Known specs:

Power output: 150 W × 9 channels (8 ohms, 20 Hz–20 kHz, 0.05% THD)
Frequency response: 20 Hz–20 kHz (±3 dB)
Signal-to-noise ratio: 100 dB (IHF-A weighted)
DAC: Burr-Brown PCM1795 (all channels)
Video: 4K/60Hz passthrough and upscaling, Analog Devices ADV8005 processor
Connectivity: 3 HDMI outputs, 7.1-channel analog inputs, phono (MM), Wi-Fi, Bluetooth, AirPlay
Power consumption: 870 W
Dimensions: 17.1" × 7.3" × 17.9" (W × H × D)