I use to own the Leben CS600 and Harbeth SHL5. Although pleasant sounding, I wasn't overally impressed with the synergy, even after changing to Sovtek EL34 or Harma 5881 tubes. For my taste I found the Harbeth's sounded better with my Audiosector Patek SE (40w/ch gainclone) amp. Using the more precise and neutral sounding Patek, with DNM reson IC and speaker cables, the SHL5 sang with greater cohesion with a tighter, punchier mid bass and neutral mid range. I also found the SHL5 responded very well with proper speaker stands and care with positioning.