A power amp should have a high impedance voltage mode input 1k ohm or greater. Why would it matter if the dac out is 10 or 1 ohm?
Ok - it depends from combination to combination.
One amplifier that is EXTREMELY sensitive to this is Stax SRM1MK2. It has input impedance of 47 kohm - it should not present any problem. IN THEORY.
Believe me, it was NOT my pleasure to basically tar and feather a prototype phono stage of my good friend, for whom I know he did his best given the budget. I did go to other places using other amplifiers for the rear end - and the phono stage, although not stellar, was more than acceptable. Using ANY of my turntables/cartridges/arms, when called upon to drive the SRM1MK2, it collapsed into something soooooo boring I would not consider listening to a single LP side with it. Lifeless, dead. Period. In this combination, at least.
This SRM1MK2 will unearth dynamic range differences in CD players, DACs , etc - mercilessly so. I will say which "DAC" is OK in this regard - it is the DAC section of the Technics SU-A60 preamplifier. By now, it is rare - it is from 1986 or so. http://www.hifiengine.com/manual_library/technics/su-a60.shtml I knew this DAC is something special the minute I upon returning from recording a piano recital to CD-R, listened at home with this DAC. Wow!!! - it did provide for better dynamic range than I heard during CD-R monitoring during the concert - but it was raw, harsh and unacceptable for long listening sessions.
Full restoration and upgrade/modification was needed in order to get the SU-A60 to listening fatigue free device. With an even better dynamic range than in stock form. It also carries one of the most undetectable tone controls out there - it will not change the character of the sound as it is usual with tone controls, only the timbre - as it should. Please see the User and Service Manuals - it can be patched/used in MANY ways - and its line section is one of the few that are actually better in the circuit than left out - can be done at a flick of a switch. There is NO electrolytic capacitor used in the modified unit - nowhere in the audio path. Not something for bean counters - it would give them heart attack on spot.
Trouble - it can only do up to 48 kHz/claimed 18 bit - ( Adrian Kingston http://adrian-kingston.com/SE-A3MK2.htm mentions the DAC of the SU-A60 "somewhere" in his pages as 16 bit device IIRC ) - be it as it may, it does sound good with Redbook. When compared to Asus Xonar Essence One, Asus lasted mere seconds - it is sooooo boring and uninvolving and un-whatever in comparison to a well modified SU-A60. Spare me the ABX sermon - Asus would NEVER pass as something approaching live sound - repeat, NEVER. Into ANY amplifier. Even to a panel of 70+ old women to whom audio SQ is not only the least important thing in universe, but beyond comprehension altogether.
So big can be differences - played from the same WAV ... - raw master that I recorded and for 100% can guarantee it was not tampered with in any way.
Despite Asus on paper being superiour and younger by - almost three decades...