From the PDF Manual for the SETi 40:
"Input level for 37 watts output • 1.5 V rms"
Many DACs will be in the 2 - 3 Vrms range...for the SE analog outputs.
"Peak power output • >70 watts" Perhaps @almarg can provide the maximum Vrms needed for peak output, should it be a factor.
Also, is this amp related or / and/or speaker related? You haven't listed your speaker.
"Input level for 37 watts output • 1.5 V rms"
Many DACs will be in the 2 - 3 Vrms range...for the SE analog outputs.
"Peak power output • >70 watts" Perhaps @almarg can provide the maximum Vrms needed for peak output, should it be a factor.
Also, is this amp related or / and/or speaker related? You haven't listed your speaker.