Hi. Just completed my own set of PCB for this amp, see pictures. I also took detailed measurements.
Here some measurements:
Sensitivity: 1.25Vin max, for 6.9Vac Out Max. into 8 ohms
Power: 5.95W into 8 ohms max.
BW (Ref 1Khz, 1V): 0.3Hz to 145Khz
Noise (gnd input): 0.08mV (Lab. power supply), 2.2mv (Standard Supply), see graph
THD (1V, see load): 0.042% (8 ohms), 0.007% (16 ohms), 0.008% (no load), see graph
IMD (1V, 1 & 2Khz): 0.007% (16 ohms)
In normal use, max volume, gnd inputs, no noise can be hear...
You can see the complete files at http://www.diyaudio.com/forums/headphone-systems/109618-krell-ksa5-9.html