$100-200 linear power supply

This is why:

the 4706 Gaincard offered excellent measured performance. In fact, almost all the measured problems I encountered can be laid at the feet of the Humpty power supply.

From the same review:

What is less good are the spikes overlaying the waveform at the signal’s zero-crossing points, which imply inadequate standing bias current in the Gaincard’s output stage. When RD writes about "a hardness or glare in the upper midrange and treble," I do wonder if that correlates with the presence of the high-order harmonics that will result from this behavior. Of course, RD also found that this character dissipated after a very long break-in period.

 

Lab 4706 Gaincard, 1kHz waveform at 22W into 4 ohms (top), distortion and noise waveform with fundamental notched out

@ericgale 

I am of the school of thought that one would be better off buying a better amplifier than sticking 2 or 3 times the cost in a power supply.

Sure, what amp would that be? It would help if you have heard this amp so you can know what type of sound I am talking about.

I'm using same amp to drive Avalon Ascendant, with WiiM Pro Plus...no "digital glare" here ...and it's down to $59.95 including shipping...

@jl35 

What made you decide on the TDA7498 and not something like the V3?