Nordost • Norse Series Bi-Wire Jumpers
It’s not unusual for high-end speakers to come with two pairs of binding posts, sometimes more. If your chosen speakers are so equipped, you have a number of options when connecting them to your amp. You can use a single set of speaker cables, using the jumpers the speaker came with to connect the other set of terminals; you can use two sets of cables to bi-wire them; or you can compromise one set of cables by splitting it and have two sets of connectors on the speaker end.
Given the prices some speaker cables can command, buying another set to bi-wire your speakers might be prohibitively expensive, at least in the short term. Butchering your current cables to facilitate bi-wiring is probably also undesirable, so the only alternative is to use the supplied jumpers. The trouble is, in my experience, the factory-supplied jumpers tend to be less than optimal. Fortunately, the boffins at Nordost have come up with a solution: the Norse Bi-Wire Jumpers.
Technical Details
Each Bi-Wire Jumper (there are four per pack, each about 20 cm in length) consists of a single 16 AWG strand of 99.99999% pure oxygen free copper (OFC), extruded over each of which is 60 microns of silver. Wrapped around the cable strand is a fluorinated ethylene propylene (FEP) monofilament thread, wound in an open helix, and extruded over that is a clear FEP sleeve. FEP is very similar to PTFE (which is most well known by its DuPont brand name, Teflon), sharing its properties of low friction and chemical inertness. Each end of the jumper is terminated with either a low-mass Nordost Z plug or a gold-plated spade (the desired configuration is specified when ordering the jumpers). For this review, I requested that each end be terminated with Z plugs.
The monofilament thread acts as a spacer between the cable strand and its FEP sheath, resulting in a dielectric which is about 80% air because the FEP sleeve never touches the cable strand itself. This is advantageous because the best dielectric is none at all (i.e., a vacuum or air), but a cable constructed using such a dielectric would be unwieldy; in addition to mechanic integrity, real world cables require a degree of flexibility.
Setup and Listening
I usually listen with my Spires bi-wired, so the first thing I had to do for this review was reacquaint myself with their sound when the factory-fitted jumpers are used. For my formal evaluation I decided to use the first two movements of Fritz Reiner’s reading of Prokofiev’s Lieutenant Kije [Classic Records/RCA Victor LSC-2150] while conducting the Chicago Symphony Orchestra, alternating between the stock jumpers and the Norse Bi-Wire Jumpers.
With the standard jumpers in place, there was a noticeable increase in grain with a commensurate decrease in resolution and air (the celeste in the second movement, Romance, is a good example of the latter). Also, a slightly metallic texture was added to sounds like the snare drum.
Replacing the factory-fitted jumpers with the Norse Bi-Wire Jumpers is the aural equivalent of removing a pane of glass, or giving a dirty pane a good cleaning. By this I mean that the improvements wrought by the Bi-Wire Jumpers are worthwhile, but relatively minor. Grain was audibly reduced and the metallic colouration I heard with the stock jumpers was banished.
Out of curiosity (and for completeness’ sake) I reverted to my usual bi-wired configuration once I’d finished my evaluation of the Norse Bi-Wire Jumpers, to see how they compared to no jumpers. I noticed a slight improvement when using the Frey speaker cable without any jumpers, but the difference was much smaller than that between the factory-fitted jumpers and the Norse Bi-Wire Jumpers. I’d heard reports of people preferring to use the Norse Bi-Wire Jumpers rather than bi-wiring, so I was mildly surprised by this revelation. A quick chat with one of Nordost’s technical support guys shed a little light on this: up to the performance level of Baldur or Heimdall, many users do apparently report a slight preference to using the Norse Bi-Wire Jumpers. However, above that performance level (and my Freys would certainly qualify!), Nordost recommend using jumpers made of the same cable: Frey jumpers with Frey speaker cables, Valhalla jumpers with Valhalla speaker cables, and so on. I’ve not yet verified this with my own ears, but it sounds plausible enough.
Verdict
Although not for everyone (people whose speakers can’t be bi-wired needn’t apply!), the Norse Bi-Wire Jumpers can offer a worthwhile step up in sound quality over those supplied with many speakers. If you’re currently skimping on your speaker cables, you should address that before buying the Norse Bi-Wire Jumpers, but if the price of the Jumpers is significantly less than the cost of a second run of your favourite speaker cable, giving them a try is, in my opinion, a no-brainer. If nothing else, they’ll give you a step up in sound quality while you’re saving for another set of those über cables!
Specifications
Description Extruded silver over 99.99999% pure copper 16 AWG
solid conductors, FEP monofilament helix and dielectric. Available with
Available with Nordost Z plugs or gold-plated copper spades.
Price $149.
Serial number of unit reviewed N/A.
Warranty Lifetime non-transferable.
Manufacturer
Nordost
200 Homer Avenue
Ashland, MA 01721
USA
(508) 881-1116
www.nordost.com
Associated Equipment
Analogue source Forsell Air Reference Mk 2 turntable and arm.
Phono cartridge Lyra Parnassus.
Phono stage Allnic Audio Labs H-1200.
Preamp Audio Research SP9 Mk 2.
Power amplifiers PrimaLuna ProLogue Sevens.
Speakers MartinLogan Spires.
Cables Phono: Nordost Frey. Interconnects: Nordost Frey. Speaker: Nordost Frey. AC: stock.
Accessories Target and SolidSteel equipment stands; Mission Isoplat; Furman Elite 15-PFi power conditioner; Audio Physic cartridge demagnetiser; Acoustech carbon fibre brush; Last record and stylus cleaning products; The Cartridge Man tracking force gauge; Spin Clean Record Washer Mk II.