Nominal power output in watts

[craigjm]

Looking at the new Ruark R2 that has recently been updated -

http://www.ruarkaudio.com/products/r2-overview

It states that the amplifier power output is "20 watts nominal power output"

How do you convert this to RMS? trying to work out whether it would be sufficient or whether I want an R4 when those are updated to the same spec which is listed as 80 watts nominal power output

[JimbobVFR]

Its a complicated subject but in general in HiFi Nominal is the same thing as RMS pretty much.

[craigjm]

Thanks for that very helpful