Like the original, the Mk2 Crossover uses a double-decker build with the firm's vertically installed discrete opamps populating both upper and lower storey plus two tightly seeded minefields of resistors tied to the frequency selectors. The low-pass attenuator sports a firm centre indent at 0 then progresses smoothly in either direction without discrete steps. All controls are firm and engage reassuringly. At nearly 28cm across, most will call this 2/3rd width against the unofficial 43cm standard openly defied by Nagra and many others. Whilst I don't anticipate many users in our sector exploiting the Mk2's newly gained filter hinges beyond 120Hz, losing the original's VU meters but adding RCA outputs surely works to our collective benefit.
For those not wishing to high pass their mains, having 2nd and 4th-order slopes on the sub entry accommodates the acoustic roll-offs of sealed, TL and ported speakers. That said, I predict that particularly on 2-way speakers, anyone comparing wide open to high-passed will find the latter's easing of the load to sound better. With this unit, you obviously paid for that functionality. After the obligatory bonnet popping, 'on' the lid went again and into the upstairs rig it was. Here the Virtual Audio Cobra loaners had moved to the room on the far end of the corridor and my usual ModalAkustik MusikBoxx monitors regained pride of place bracketing Zu's 15-inch sub now sat on a spare platform for extra isolation from a suspended wood floor.
Other than by small red power LED on the fascia's upper right, the SPL box attracts no special rack attention and emits no signature studio airs of rack handles, endless knobs, fiddlers and twitchy meter needles. The on/off toggle for the high-pass/full-range function doesn't cut our subwoofer feed. It just swaps between filtered/unfiltered mains. Changing filter freqs incurs no pops or dropouts to happen instantly if manually. My first trial duplicated the domestic setup to see whether the SPL left any discernible finger print on the lion's share of the bandwidth, i.e. the ~70-25'000Hz of my sealed German 2-way monitors in their stacked acrylic sliver cabs with external crossovers.
Musical cats not chairs.
This being my smaller room, playback levels here lean toward the intimate and mellow. Under those conditions, the Mk2 got a squeaky-clean bill of health. I heard nothing whatever untoward that gave away the addition of an active circuit. This do-no-harm observation wasn't the end of my diagnosis though. My holy shit moment simply meant the ground floor, more rambunctious fare and higher levels commensurate with a bigger space.
