As modules, they can be used in series ad infinitum. Effectiveness is cumulative. As three were sent my way, I intended to investigate that. The inherent 'firewall' tech isn't new but something LessLoss have pursued and refined over many years. The basic approach involves a proprietary skin-filtering method to block HF noise contamination migrating to and from our audio gear via the network of power cables. The LessLoss recipe is purely passive, hence there's no active circuit, no caps or coils. The first implementation of the concept was the Dynamic Filtering Power Cable or DFPC, then a very large €5'000 wooden power strip, then downscaled small multi-layered PCB modules Srajan covered here. The current Firewall lineup is based on the most advanced revision of this tech which has nothing in common with the previous takes other than the same core principle.

The passive parts inside today's box are radically different than they were in the now discontinued LessLoss filtering circuit boards. CEO Louis Motek explained how just a few years back, the new 3D-printed solution he exploits now wasn't yet available. It's based on precisely positioned directional metallic particles within a thermoplastic carrier and physically arrives as a cylindrical object of "a much lower and more stable noise floor than ferrites". A generous drop of glue inside my loaners prevented a peek inside to actually see this 3D-printed barrel of enormous 20mm² copper per line to treat live, neutral and ground separately. The ground lines of earlier Firewall iterations remained unfiltered.

The company's present Firewall family consists of three items: today's $1'272 flagship, a $654 non-C-MARC version and a DIY install module. With the same filter core inside both assembled versions, the significant price gap begs the question why. At first glance one would associate the nearly doubled price with the attached C-MARC cable but that's just one difference out of four. The more expensive C-MARC version's six internal copper bars are hand-polished, its C13 plug installs the in-house laser-cut vibration absorber and a special glazing applied to its Firewall module enhances vibration damping by mating this key piece more readily to the wooden enclosure. Little things they might be but the hifi devil is always in the details. Or so we're taught in Sunday school.

To review the LessLoss C-MARC Firewall 64X modules, a fidata HFAS-S10U handled storage and transport duties, a LampizatOr Pacific DAC with Living Voice 300B and KR Audio 5U4G rectifiers the D/A conversion. Then it was either the team of Kinki Studio EX-M1 integrated and Boenicke W8 speakers or the Trilogy 925 integrated and Buchardt Audio S400 monitors. All key components connected via LessLoss C-MARC power cords to a GigaWatt PC-3 SE EVO+ power conditioner which hit the wall outlet via LC-3 EVO power cord also from GigaWatt. C-MARC cables showed up on the speakers, Amber-modded Excellence interconnects by Audiomica Laboratory found their place between sources and amps whilst the Buchardt Audio S400 monitors topped Soundstyle Z1 stands. Three 64X allowed for various test combinations. Logic would suggest to use one ahead of my power conditioner to spread the noise-killing love to all devices, then add the next Firewall in the same junction, then the third and from there work my way downstream.