Consider those goals and it becomes rudely apparent that the vast majority of even the most expensive racks are only addressing the third of those priorities – and that in doing so they are often compromising the levelling requirement. It’s interesting to note that HRS are now offering solid feet as an alternative to the flexible/weight-matched isolators on their platforms – a solution that makes their racks more stable and (generally) creates a more consistent level across the different shelves, which will no longer be canted by equipment that loads them unevenly (ie. most of it). It’s also worth noting that HRS is one of the few companies that offers a genuinely comprehensive approach to chassis damping and mechanical grounding (our first and second priorities, remember). Using the (much cleverer than they seem) Nimbus and/or Vortex footer, with correctly selected damping plates, throughout a system, can have a pretty dramatic impact on its musical performance. But you rarely see them being used, or used comprehensively, even in the HRS rooms at shows. Why? One suspects it’s mainly because, aesthetically speaking, it’s a hard sell. Big expensive racks on the other hand…
This is not to denigrate HRS in any way. They are, as I’ve already pointed out, one of the very few companies that actually address the core issues of signal isolation directly and effectively. In fact, my experience suggests that, just as most rack manufacturers have the problem upside down, most people selling HRS kit have the range upside down too. Rather than starting with a rack and then upgrading the platforms and eventually, maybe, reaching the point where you might add a few damping plates or footers, it’s those afterthought ‘accessories’ that you should actually start with. Used on even a good, basic rack like a Quadraspire Q4 Evo, they produce surprisingly impressive results.
All of which is a long-winded way of making the all-important point that when it comes to equipment supports, what’s physically in touch with the equipment’s chassis is what matters most. Which brings me, finally, to the subject of this review, the unusual case of CH Precision, Acouplex and the unusual but efficacious ReFract panel.
Just in case there’s anybody out there who isn’t familiar with the CH equipment, either in person or second-hand, it’s worth describing several of the unusual features shared by the brand’s products. In case the preamble hasn’t warned you, CH Precision take the mechanical grounding and levelling of their equipment seriously. Far more seriously than most. So, where you find rubber feet or solid cones on most equipment, the CH products are equipped with simple circular disc feet, each with a groove around its periphery that holds a polymer O-ring. This protects the supporting surface when placing the equipment, but it’s not designed to act as the interface between the unit and its supporting surface/structure. There’s a threaded hole through the middle of the foot and the company supply titanium or hardened aluminium ‘spikes’ to drop through that hole and lift the equipment clear of the supporting shelf, making for a precise, four-point contact that allows users to level the unit and also serves to drain energy out of the chassis and into the (hopefully dispersive) supporting shelf. To make the system as efficient and easy to use as possible, the spikes interface with large diameter stainless-steel ‘pads’ that are securely fixed to the chassis base plate. A tube rises from that base to meet the top-plate, where a removable cap allows the owner to drop the spike into place and adjust it from above. All very clever and pretty effective. But that doesn’t mean that it can’t be improved. The titanium spikes are a case in point. Supplied as standard with 10 Series units, they are an optional (and worthwhile) upgrade over the hardened aluminium versions supplied with the 1 Series. Even so, the unit’s ability to shed unwanted energy can be further improved. As efficient as the spikes are, they aren’t perfect and some energy will remain or be reflected back into the chassis plate. Contrary to the fond hope/article of faith evinced by many an audio manufacturer, spikes are a long way from being mechanical diodes. You can’t guarantee they’ll pass all the energy in one direction, or prevent energy entering in the other. Those shafts in which the spikes sit can vibrate too, while the 1 Series top-plate screw caps that connect them directly to the unit’s cover, create a series of mechanical feedback loops. It’s one of the reasons that I prefer the sound of the 1 Series units without the top-caps installed.
