Is it worth adding a flatcap to a nac 112 and nap 150 ,would it make a big difference or is it not worth the extra cost
It’s not that high a cost imo and the 150 doesn’t cover itself in glory regarding pre-amp power. Go for it but make sure it’s within service period. If you don’t like it you can sell it on for what you paid for it. However, you might consider the later derivatives of the 112 like the 112x or 122 which are much better regarded, particularly the latter. Of course it’s all minefield and extra cost but why do we do this to ourselves
In principle, yes.
As has been pointed out, a later and better variant of your NAC112 may be preferable. The latest was the NAC152XS.
Such a preamp would take its power from the NAP150 so it will be best to get the 150 serviced, for instance by Class A or Naim.
A NAC152XS, NAP150 would definitely benefit from a serviced FCXS or FC2x, ideally the former.
Edit: But to go back to your original question, your NAC112 with a serviced Flatcap 2 and a serviced NAP150 will also be a very nice amplifier. Hope that helps.
I’m assuming you are going “used” for the flatcap? If so, try and get one with the black SNAIC 5 included.
Would a hicap be ok or stick to a flatcap