Again thanks. I guess the idea is to go with DAC --> L70 --> poweramp, to get myself ready for more demanding floorstanders.@Bleib The 'ohm debate' is mostly about relative low input impedance of for example a preamplifier or amplifier in combination with a relative high output impedance of the connected device. For example the input impedance of the Topping Pre90 is 2k Ohms (Balanced). When connecting a DAC with output impedance of 200 Ohms that would make an output-input factor of only 10 (2000 divided by 200) which is low. You better use a DAC with lower output impedance of preamp with higher input impedance.
About your SMSL DO100 DAC: according to Headfonia the input impedance of the SMSL DO100 is 100 Ohms. So when connecting this DAC directly to one of your NCore amplifiers with an input impedance of 47k Ohms, that should be no problem because the output-input factor equals to 470 (47000 divided by 100).