Audio Cables

Legenburg Zeus Interconnects and Speaker Cables

cablesIntroduction

Over the past few years, several new companies that manufacture A/V cables have emerged. Most of them sell these cables at entry-level prices. The cables are good, basic designs.

Legenburg, although a new cable company, is definitely not in the entry-level arena. It is high-end.

Does that mean the cables are really fancy? Yup. Expensive? Yup.
cables
Will the fancy, expensive cable critics laugh? Probably. They always do.

Zeus

We reviewed the Legenburg Artemis cables some months ago. The Zeus differ from the Artemis in that the conductors are pure silver - called mono-crystal rectangular pure silver (RCRPS). The connectors are rhodium-plated mono-crystal copper.

Like the Artemis, the conductors are thin ribbons and are in several sizes, each one insulated with foamed Teflon® dielectric. Braided shielding is silver-plated.

The conductor design and layout is patented.

Specifications


Balanced Interconnects
  • Conductors: Mono-Crystal Rectangular Pure Silver (MCRPS) - Different Conductor Sizes
  • Dielectric: Porous Teflon Surrounding Each Conductor
  • Shielding: Tinned Braided Copper
  • Terminations: Rhodium-plated Mono-crystal Copper XLR Plug
  • MSRP: $1,750 for 5 Foot Pair XLR
  • Conductors: Mono-Crystal Rectangular Pure Copper (MCRPS) - Different Conductor Sizes
  • Dielectric: Porous Teflon Surrounding Each Conductor
  • Shielding: Tinned Braided Copper
  • Terminations: Rhodium-plated Mono-crystal Copper Banana Plug or Y Spade
  • MSRP: $7,950 USA for 10 Foot Pair

Legenburg

In Use

The review set consisted of two five-foot pairs of XLR interconnects and one ten-foot pair of speaker cables with spade lug terminations. Associated equipment included a McIntosh MCD201 SACD player, Lamm L2 Reference preamplifier, Lamm M2.2 monoblock power amplifiers, and Carver Amazing Mark IV ribbon speakers.

I used the cables for lots and lots of music listening over the past weeks, and the first thing I have to mention is the astounding build quality. Even the interconnects are like the proverbial garden hose in size and stiffness. This can cause a problem if the area behind your player and preamplifier is small.

Fortunately, I have plenty of space, so I could utilize a wide bend radius. And this is a case where you want the speaker cables to be the shortest length possible so they can go direct from the amplifier binding posts to the speaker binding posts. This way, you don't end up with cable that has to be coiled (although the bench tests indicated that coiling the speaker cable did not cause any increased inductance). Lastly, spade lugs for the speaker cables are really the choice here, rather than banana plugs, since the cables are so stiff and heavy.

I did not hear any differences in the treble, between the Artemis and the Zeus, but the bass did seem somewhat tighter. As the bench test section will show, the resistance of the speaker cables is very, very low (silver is a better conductor than copper), and this may have improved the high current demand handling. Difficult to say really. But, I was impressed enough that I am considering the Zeus as my new reference cable in the lab. They just seem to be made to the same high standards as the rest of the equipment in the lab, and that is important to me. I now think that speaker cables should have a metal braid shielding, as they can act like radio antennae just like interconnects. Although the RF in the speaker cable would be small compared to the speaker voltage at high volume, it would be comparable to the RF level vs. voltage in the interconnects at lower volume. And, RF is not good to have in the A/V signal path. It can interact with frequencies in the audible band and cause distortion. A small amount of distortion? I think so, but why not remove it if you can?

On the Bench

I used a three-foot RCA interconnect ($1,280/pair) for the interconnect bench tests because I can't measure the impedance on three conductors in an XLR cable (it has to be two conductors).

I measured 30.5 pico-Farads/foot capacitance and 0.27 micro-Henries/foot inductance for the interconnect (3 feet length).

The impedance for the interconnect stayed below 0.1 ohm all the way through the audible band, except at about 18 kHz and above, where it maxed out at 0.15 ohm. The electrical phase stayed within +600 (inductive) except at 220 Hz to 500 Hz, where it went to about -200 (capacitive). This is superb performance.
cable impedance not coiled
For the speaker cable (10 feet length), I measured 49.7 pico-Farads/foot capacitance and 0.17 micro-Henries/foot inductance.

The phase for the speaker cable varied between +400 and -600 when not coiled, and +400 to -200 when coiled. The impedance stayed below 0.1 ohm pretty much all the way through the audible band. The changes in the coiled configuration indicate the movement towards more inductive behavior. The impedance at 10 Hz can be taken as the DC resistance, which is 0.1 ohm or less for both cables tested.
speaker cable impedance not coiled

speaker cable impedance coiled

All impedance parameters - inductance, capacitance, and resistance - are affected by each other. When I coiled the speaker cable, the graph went more capacitive at some frequencies and more inductive at others, and the impedance decreased slightly in the low frequencies while increasing slightly in the upper frequencies. The fact that the phase hovers around 00 does not mean there is no inductance or capacitance; rather it just means the effects of inductance and capacitance are balancing each other out. Legenburg has optimized their designs according to what they think is the best outcome.

Conclusions

The Legenburg Zeus cables are truly an astounding product. I was surprised to find them improving on the Artemis, but they did, just a little, and noticeably. They are very expensive, but having pure silver - and lots of it - in the conductors, makes them a surprising value.