SRS PERF-10 with the integrated 115V switching supply makes a noticeable improvement over stock K-01X in resolution, texture and timbre, reduced digital smearing, LF and mid-bass articulation, ambient space and depth cues. It moves everything in the right direction, as compared to the more subjective and subtle differences between the various up-sampling and filter options on the player.
Adding a 12Vdc Paul Hynes linear PS moved all of the above up a notch. However Paul has long lead times and his communications can be hit or miss. The Uptone PS is also well regarded and there are doubtless other good ones out there.
When thinking about 10 mHz alternatives to G-01, consider that you need a 75 ohm interface. The most common and less expensive lab versions have 50 ohm interfaces.
SRS claims to have low phase noise relative to others. I suspect that's why Esoteric chose to source it from them. Other than clock accuracy (which for all rubidium clocks is by definition excellent) low phase noise is probably the critical determinant of performance. Improvement to PS may affect this.
Personally I couldn't justify the cost difference between PERF-10 and G-01. The only thing the G-01 has over the others is its 22 mhz oven-controlled master clock that is slaved to the 10 MHz rubidium clock when a 22 MHz clock link is selected. This off-loads the 22 mhz master clock in the K-01. There may be a difference between 10 and 22 clocking. However I was told by Esoteric tech support that the Japanese that designed the -X series prefer the 10 MHz clock link. That recommendation was sufficient for me to proceed with a PERF-10.
Hope this helps.
