- Dec 7, 2014
Search is so useful:And I guess to say it another way, there are some measurements where JA's AP may have been a limitation with his Dave measurements and very clearly some measurements where his AP wasn't a limitation for measuring Dave and Mojo (and bettered by Holo May and Weiss DAC).
Rob's comments on the AP used in Stereophile's DAVE review
The APx555 is a much better instrument than the SYS2722. Chord have one, and when they measure Dave they get -118dB DR - as opposed to -128 dB with Dave into the APX555. The SYS2722 is simply inadequate to measure Dave - indeed John Atkinson confirmed to me in January that they have now acquired an APx555, so I hope to see updated measurements. But even the APx555 has a tough time with Dave, and I am unsure how much THD is actually down to the APx555, as Dave's level is at the innate level of the 555... It's one reason for the Davina ADC project, so that I can get better measurements.
The analog noise with Dave is at -128 dB; I could get better than this, but this would be at the cost of higher THD, which is damaging from a SQ POV. Moreover, the APx 555 can't measure better than -133 dB anyway, and the noise level is so low that it is immaterial subjectively - it's only when noise changes with signal that it becomes important, and as already discussed, the noise change with signal is unmeasurable.
We've been here before...