An affordable AV receiver is always a good option to consider, so Yamaha AVENTAGE RX-A680 vs Onkyo TX-8140 comparison definitely makes sense.
A significant difference between the receivers in the number of channels, Yamaha AVENTAGE RX-A680 has 7.2 versus 2.0 for Onkyo TX-8140. Regarding power, then AVENTAGE RX-A680 has such a W/Ohm ratio - 115/8, 145/6 when TX-8140 has a power of 80/8, 110/6. The THD is the same and is 0.08%.
Characteristics of digital to analog converter (DAC) are different, Burr-Brown 384 KHz/32-bit for AVENTAGE RX-A680 and AK4458 384 KHz/32-bit for the TX-8140. Only the AVENTAGE RX-A680 supports Bi-amping feature. Each of the AV receivers can transmit an audio signal directly to the amplifier and bypasses any DSP processing. Rivals from our review have Bluetooth support. Spotify can be used on each receiver. The AVENTAGE RX-A680 can work with the audio stream from Deezer, TIDAL, Pandora, Napster, SiriusXM, Qobuz, and the TX-8140 can receive a content from SiriusXM. Only the AVENTAGE RX-A680 provides HDMI signal transmission in standby mode. The AVENTAGE RX-A680 can scale the input HDMI signal, unlike the TX-8140. Dolby Vision technology found support only on the AVENTAGE RX-A680. Only the AVENTAGE RX-A680 supports HDMI Audio Return Channel (ARC). The HDMI eARC is available only on the AVENTAGE RX-A680. Of the two receivers in our comparison, HDMI CEC is present in only the AVENTAGE RX-A680. The TX-8140 has a built-in phono stage for connecting a vinyl player. An ECO mode is only available for the AVENTAGE RX-A680. Both AVENTAGE RX-A680 and TX-8140 can be configured using the Setup assistant.
Only the AVENTAGE RX-A680 has a Dolby Atmos multichannel audio format support. A surround technology DTS:X is supported only by the AVENTAGE RX-A680.