Klipsch R-51PM might work for you. I believe it has a phono input and a 3.5 mm input that you could adapt to rca. The main issue is finding powered bookshelfs with a phono preamp and multiple inputs. They kind of reach up into the higher price range with the more features and inputs
I understand. The point is, as I’m putting the devices together in steps, it would be no problem to have something like a switchbox added to the setup down the road. also the phono preamp would not be a big deal as I could spend then that money on the turntable when I get it.
Now, technical question, as I am now waiting delivery of the DX7 DAC, connecting the speaker to the DAC via optical would use the internal DAC or the DAC which is inside the topping?
You would want to connect the topping to your pc or whatever source using usb or optical if you prefer, and then rca out into the speakers.
So then what is your leftover budget for the speakers?
That’s right, then the rca input would be used to connect the DAC, and the Phono in would then be unavailable (in case I bought the Klipsch).
For powered speakers I would stay below 500/600 $
Check out the vanatoo transparent zero or one. Great speakers with lots of features
I just checked and it looks like it is damn impossible to find these in the EU. It’s being quite frustrating (ordering on Amazon appears to be very very very expensive).
Audioengine A5+ (non wireless)? Has sub out and powered with 2 analog inputs
Sorry about some of these recommendations because I don’t know pricing and availability where you are
Hahaha! no worries, thanks for your suggestions 
The audioengine are available here, in wireless and classic variant. I’ll take a look at those, they seem better than the klipsch sise.-wize but still with some ooompf
Those will probably be easier for a desk then the Klipsch
yep they look like a viable alternative. Now I’ll wait for the delivery of the DAC and then I’ll try and make up my mind on the speakers 
So! I’m back with questions.
I narrowed down the decision to either the NAD C 316BEEv2 or the Cambridge Audio Topaz AM10, coupled with the Q150 from KEF for desktop use on a computer (gaming, movies and of course a lot of music) and the Topping DX7s (great dac!).
My question is: in case I get the NAD amp, would there be a way to add a sub afterwards ?
No, unless you get a sub with speaker level inputs or do some rca splitting and hassle
Can you make an example of such a sub? I want the NAD actually but I am not sure if I might have to add a sub as well with the q150 in the future
Definitive Technology ProSub 800 or Polk PSW505 come to mind around the $300 range. It passes through the speaker outputs and gets it’s signal from there
Sounds good, that means that I can get the NAD 
Thanks M0N!
One last thing, would something like a subwoofer amp (like this one https://amzn.to/2zGgNQV ) be also usable without a sub output?
I don’t see a problem. I haven’t used an amp like this, but it will work pretty much the same way the other subs would
Thanks man, I pulled the trigger on the NAD amp (found a very good deal on it) + KEF Q150 
Pretty happy with the final decision!
Can’t wait to hear your impressions when you get it all set up!