Both! You can't see the forest through the trees?
These are both in reference to a source with a weak tube output stage, geeeeish!!
And don't even come into play if the source has a good low solid state output impedance.
I can see forests pretty well and also am pretty good at contradictions. Since you did write both statements I accept that you believe both of them but just so you know, if that is true it is also true that you are contradicting yourself.
Perhaps it would help if you defined what is meant by a 'weak tube output stage' (since tubes can easily drive headphones if set up properly; we can do it with our UV-1 preamp) and also what you mean by a 'good low solid state output impedance' as clearly Oppo, Wadia, dcS and others apparently do not qualify. I am assuming you mean 'output impedance', perhaps you have some numbers?