I did not try ESS recommended opmap circuit. What I did try though is latest version of trident dual shunt from twisteadpearaudio, paul hyness shunt, Salas Ref-D, lt3042. All of them were very good, yet for the image stability, clear background LifePo4 is the winner. It is like everything became, clear, calm and relaxing. It reminds me my pcm1704 dac that I used to build some time ago.
This is what we found many years ago. On most applications straight
batteries were superior to any form of regulation. At that time regs like 3042
were not quite out and I thought that these might surpass batteries
performance.
I'll be interested to see how super (ultra) caps go. Also worth a try is
inserting a low ohmic value (say 4.7R) series resistor after a VHQ reg (3045)
feeding the super cap. The theory here is whatever sonic influence the reg
has, it is attenuated by 40dB or so, depending on Z / size of cap.
Also I'm not sure of the HF performance of supercaps. Have to look into this.
T