At the Onkyo’s retail price of $499, Yamaha’s contender is the A-S501, not the 301.
The A-S501 has the stronger power supply - two 12000μf capacitors and it’s rated to 220 watts at 2Ω for dynamic peaks. It’s "minimum" RMS power at 8Ωs is 85 watts/Ch - both channels driven.
The following review includes some measurements for ths A-S500 (501 sans DAC). It actually outputs more power than its spec sheet suggests.
https://www.avhub.com.au/product-reviews/hi-fi/yamaha-a-s3000-amplifier-review-and-test-395562
(Click on "Review and Test" link)
The A-S501 has the stronger power supply - two 12000μf capacitors and it’s rated to 220 watts at 2Ω for dynamic peaks. It’s "minimum" RMS power at 8Ωs is 85 watts/Ch - both channels driven.
The following review includes some measurements for ths A-S500 (501 sans DAC). It actually outputs more power than its spec sheet suggests.
https://www.avhub.com.au/product-reviews/hi-fi/yamaha-a-s3000-amplifier-review-and-test-395562
(Click on "Review and Test" link)