I am running two AS-1 instruments, one with the original AS-1 "black box" and one with some of the components of the black box modified to extend the range to lower periods.
The figure below shows a comparison of a distant earthquake from each system.
The surface waves are almost impossible to see with the original black box and are more prominent with the modified electronics. The surface waves are clearly visible on the long-period filtered record from the nearby Corvallis broad-band station (COR).
Here are links to unfiltered .SAC files from CHOR and CEOR.