Tried the SX52 op amps and found that OPA1656 sounded more clear in the mid-range with comparable bass response, at half the cost.
In my experience, the discrete op amps cost too much and don't contribute a proportional improvement in sound quality.
The Douk A5 is a remarkable small amplifier that performs well above its price class and is replacing a high bias class AB amp in my own system.
For under $130 total with upgraded op-amps & 36v power supply, it is hard to beat.
what front-end/DAC and speakers were you using?
