Will DAC always sound better going straight into a Power Amplifier?

 Typically not. The sound can often sound at first blush, but it looses heft and musicality. While there are folks that have components that work to skip the preamp. That is not the most common experience by a very large margin. Most folks go back to a preamp to get the best sound. 
 

If your objective is to put together a preamp-less system, it can be done… it is difficult, but some folks claim they have done it. I’ll keep the magic with my preamp.

using a vintage restored Yamaha solid state preamp 

That would not be my first choice.

My schiit dac didn't have enough potential.  My Chord does  So not always.

Ok, can you all recommend me some good vintage or 90's solid state preamps that could pair well with modern DACs like the Musetec 005 or Holo Audio May?  I want to do a vintage solid state preamp for now because i should be able to find it cheaper, and then do some restoration vs. a couple-thousand dollar tube preamp like Audio Research.

I had suggested the Yamaha preamp because of one of its stats:

Frequency response: 5Hz to 100kHz

This is being discussed on another thread, the most general common answer is NO, a pre-amp is still required for better SQ. Personal opinion every time iv tried to go direct from DAC to Amp it never sounds as good as a very good pre-amp in the chain.

However, if you are lacking a good pre---then its possibly better just to go direct.