The author compared V5 to our own previous generation operational amplifier (V4) and discrete AudioFEEL OPA301b. He found that V4 couldn’t match V5 in overall sound quality and soundstage depth. OPA301b was very close in performance, with better gain capability for the price of agression of the sound. He preferred V5 in DAC section above all of them and found OPA301b more as a great supporting amplifier for V5 when inserted in AMP section. The only small complain was about soundstage width, but overcamed by other advantages during long listening sessions.
All amplifiers were tested on AIM SC808 sound card, Matrix M-Stage HPA-3B balanced headphone aplifier and NuForce DAC-80 digital to analog converter.
Original review:
(Link)