The Yamaha AVENTAGE RX-A1080 vs Denon AVR-S660H comparison proves that these receivers have many common features.
A significant difference between the receivers in the number of channels, Yamaha AVENTAGE RX-A1080 has 7.2 versus 5.2 for Denon AVR-S660H. Regarding power, then AVENTAGE RX-A1080 has such a W/Ohm ratio - 110/8, 170/4 when AVR-S660H has a power of 75/8, 100/6. The THD is 0.06% for the AVENTAGE RX-A1080 but 0.08% for the AVR-S660H.
Characteristics of digital to analog converter (DAC) are different, ESS SABRE 384 KHz/32-bit for AVENTAGE RX-A1080 and 192 KHz/32-bit for the AVR-S660H. Only the AVENTAGE RX-A1080 supports Bi-amping feature. The Yamaha AVENTAGE RX-A1080 can transmit an audio signal directly to the amplifier and bypasses any DSP processing.
WI-FI modules have the same characteristics: 2.4/5GHz. Rivals from our review have Bluetooth support. The Apple Music service is implemented on considered devices: AirPlay, AirPlay 2. Spotify can be used on each receiver. The AVENTAGE RX-A1080 can work with the audio stream from Deezer, TIDAL, Pandora, Sirius XM, Napster, Qobuz, and the AVR-S660H can receive a content from Deezer, TIDAL, Pandora, SiriusXM, Napster, SoundCloud.
HDMI signal transmission in standby mode is implemented in each of the devices. Both rivals can scale the resolution of the incoming HDMI signal. The HDR standard - Dolby Vision is supported by these receivers.
The Yamaha AVENTAGE RX-A1080 has 8/3 HDMI inputs/outputs versus 6/1 HDMI connectors of the Denon AVR-S660H. The HDMI Audio Return Channel (ARC) feature supports both devices. HDMI eARC is available in each model. The Consumer Electronics Control (CEC) feature is present in most modern AV receivers and the models in our comparison are no exception. The AVENTAGE RX-A1080 supports the protection of digital content of the standard HDCP 2.2, versus HDCP 2.3 in the AVR-S660H. These compared receivers have a built-in phono stage for connecting a vinyl player. The AVENTAGE RX-A1080 supports voice control via Amazon Alexa, Google Assistant, and the AVR-S660H - Amazon Alexa, Google Assistant, Siri, Josh.AI. It is also worth noting that the ECO mode is presented in each of the receivers. Both AVENTAGE RX-A1080 and AVR-S660H can be configured using the Setup assistant.
Only the AVENTAGE RX-A1080 has a Dolby Atmos multichannel audio format support. A surround technology DTS:X is supported only by the AVENTAGE RX-A1080.