As a longtime user of Nordost’s cable and AC-power products, my ears opened wide when they released their three QKore Ground Units and QKore Wire at High End 2017, in Munich. While I’ve never questioned the importance of proper electrical grounding, to prevent problems with safety and noise—the latter including measurable noise generated by transformers, appliances, LED lighting, power supplies, and Bluetooth, WiFi, and cellular devices—I couldn’t fathom what difference a passive grounding device might make in a high-end system that, in my case, is fed by an 8-gauge dedicated line with its own copper ground rod driven into the terra infirma of the fault-ridden Pacific Northwest.
From Nordost’s Michael Taylor and Michael Marko, I soon learned that their three Ground Units—the QKore1, QKore3, and QKore6—were intended for all systems, including those with dedicated lines and grounding rods. While Nordost counsels against removing grounding rods, the efficacy of such rods seems to vary with season, temperature, and soil salinity. When the soil dries out, you have to drive a grounding rod very deep to achieve effective grounding.
“It has been said that keeping the ground moist and salty enhances the electrical connection to earth,” Marko explained by phone. I envisioned myself, in bathrobe and pink fuzzy slippers, daily toting an iridescent green watering can filled with salt water to the exterior corner of our detached music room to water my grounding rod. I also imagined the imminent appearance of people in white coats, intent on grounding me permanently.
The QKore, which acts as a manufactured ground reference—a point of zero potential—includes a “low voltage attractor plate” (LVAP), made of a proprietary alloy, that avoids the variability of the organic materials that constitute soil and that are affected by temperature and/or humidity. The QKores’ precise contents—and the names of other companies involved in their development, if any—are secrets kept so close to the corporate chest that I fully understand why anyone who has neither attended one of Nordost’s demonstrations nor tried a QKore at home would raise at least one eyebrow at these things, if not reject them out of hand.
The QKore1 ($2499.99) includes one 2m-long banana-to-banana QKore Wire and one QBase Ground gold-plated binding post, and is designed to ground the primary power distribution block/conditioner/regenerator/distributor. The QKore3 ($3499.99), with one 2m RCA-to-banana QKore Wire and three QBase Ground multi-use binding posts, is intended to ground audio circuits on the secondary side of the power supply. The QKore6 ($4999.99) combines a QKore1 and a QKore3 in a single box, and comes with 2m runs of banana-to-banana and RCA-to-banana QKore Wire, as well as: three multi-use binding posts for audio circuits, two posts for monoblock amplifiers or other components, and a single QBase Ground post for the primary power product.
QKore Ground Units are intended, ideally, to be connected to as many system components as possible via Nordost’s patented QKore Wire ($359.99 each for a 2m length). This comprises Nordost’s patented Mono-Filament technology of a silver-plated copper conductor insulated with extruded fluorinated ethylene propylene (FEP) insulation, aka Teflon. The wire is solid, to better conduct resonance. Marko explained:
“Any wire that conducts AC physically vibrates. All of our top [power cords] separate conductors from one another, and use mechanically tuned lengths to minimize resonance. Imagine a wind chime. When it normally hangs in the wind, the chimes are separated, but when they touch, they ring like bells. Now, imagine those chimes tied together with a string. If you were to hit those, they would not ring; they would thud. That’s a lot like what we do. Instead of trying to damp resonance with filler and foam, we get better results when we control resonances in a less damped fashion.”
The QKores address two different aspects of ground noise in audio systems. Pre-transformer ground noise (AC), which comes out the wall, is addressed when you attach a QKore1 to a power product’s ground post. Post-transformer ground noise (DC), which lives in the audio circuits of the audio components proper, is addressed when you attach a QKore3 to those components’ open jacks or ports: RCA, XLR, USB, BNC, Ethernet, etc.
Rather than analog, Taylor prefers open digital connections, when available, because digital tends to carry more noise. As for RCA vs XLR, he said, “I tend to get the best results when I connect QKores to single-ended (RCA or BNC) connections. However, it is very dependent on how the manufacturer designs the circuitry. While in cases where the balanced circuitry has more noise in it, balanced connectors should be used, I’ve found that a higher percentage of components benefit most from pulling noise from the single-ended circuit.”
To further reduce noise caused by vibration, Nordost advises keeping QKores off the floor. “The QKore is a resonant sink as well as an electrical-noise ground sink,” Taylor said. “Putting it on three Nordost Sort Kones creates a grounding path for resonance to travel out of the unit.” While Marko prefers titanium Sort Kones ($369.99 each), he acknowledges that some audiophiles prefer bronze Sort Kones ($149.99 each), or a combination of them. Those who lack space on their equipment racks can put QKores on the floor atop Sort Kones. Each of the QKore’s removable rubber feet conceals an indentation designed to accept a Sort Kone’s pointed top.
An ideal setup for an ultra-high-resolution system consists of a single QKore1 for the power product, and a separate QKore3 for each of three other components. While you can theoretically double up connections by using two wires to ground two components to each binding post, Taylor says that, for maximum efficiency, each component should have its own QKore binding post.
The most cost-effective Ground Unit, the QKore6, can accommodate a power product and five audio components. The two Michaels claim that, if budget and space permit, going with a separate QKore1 and QKore3 instead of a single QKore6, and connecting one component per binding post, produces the greatest reduction in noise.
Setup and Choices
Nordost sent me single review samples of the QKore1, QKore3, and QKore6, along with sufficient QKore Wires and Sort Kones to accommodate the three components I was using while doing the listening for my review of CH Precision’s I1 integrated amplifier (Look for it in the February 2019 Stereophile). Lacking was a QKore Wire with USB-A termination to use on the MacBook Pro computer I’d installed for that review: I’d forgotten to ask for that Wire, and they take a while to build.
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COMPANY INFO
Nordost
93 Bartzak Drive
Holliston, MA 01746
(800) 836-2750
www.nordost.com
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