I have a friend who likes building electronics from kits and is really good at it. He does months of research, picks the best parts and the builds are works of art.
A few years ago he built an
Ultrapath linestage preamp. The power supply was in a separate case with an umbilical cord just like the big boys do. The preamp always had a low hum. Build #2 had the power supply in the same case as the electronics, hum was gone. Probably something to do with the ground plane differential.
Van Alstine tube preamps have six active high voltage regulators, one for each tube section. This design takes supply noise and interaction down to nearly zero. In addition, there are separate regulated power supplies for the tube heaters and the headphone amplifier. Smoothing capacitors are carefully selected modern, high-reliability, high-capacity units. Their amps have are no unregulated power supplies - anywhere! I wouldn't mess with AVA or any other electronics from a reputable manufacturer.
Just because you think you know more than the designers the unknowns can (and will) appear and bite you in the ass.
But if you are building one of the DAC or preamp kits from eBay then a lab or Acopian power supply will work.