Preamp advice

... preamp without breaking the bank.

https://forum.audiogon.com/discussions/schiit-vallhalla-3

Three sets of speakers?

You want the preamp to be the best component in your system... or if all components are equal then equal. 

I would look for a used Audio Research preamp. Preferably a Reference 3 or newer. You get natural and musical as well as outstanding imaging. Typically for budgeting a good rough figure is 30% speakers (one pair) and 20% preamp, phonostage and turntable... 10% cables, interconnects and power cords. 

But most importantly the preamp is the soul of your system. given your speakers and amp... I would not drop into the budget category like Schiit... it fits the will not break the bank part really well.  I would concentrate on older audiophile products and reach as far as you can... don't try and get by or your system will be highly compromised of it's potential. 

I don't think you can do better:

https://www.usaudiomart.com/details/650263291-dehavilland-ultraverve-iii/

Read one of the giants of audio about this unit:

https://www.enjoythemusic.com/magazine/equipment/0404/dehavilland.htm

You'll thank me.

I'm not the seller.