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Positive Feedback ISSUE 30
march/april 2007


We sent out the same 20 questions to 50 manufacturers, the following are their responses. The intent of the survey is to address basic questions as to design along with any questions raging on various sites, while minimizing potential chest-thumping and friendly, or unfriendly, bashing of others....

Click here to read the other interviews in the series.


Sean Casey of Zu
by PFO

PFO Why do cables make a difference? Interconnects, speaker, and AC cords?

Sean Casey For Zu, cables are the last on the list. Save yourself a ton of time, money and frustration—know the sound you want. Get the right loudspeakers for your sense of music and sound, find the right amp to feed ‘em, then get busy on your analog and digital players. With a system that is making music, it's time to look at cables. DON'T use cables as tone controls—it's a trap that will have you spending more money on wire than on music! If your system has a timbre problem look at your room, amp, speaks….

Yes, interconnects and loudspeaker cables can make a large contribution, as can power cable, though not as often. Each type should be looked at individually. Why do they make a difference? Here's a few reasons. RCA-type interconnects patch together gear with a super small power factor, where impedance makes very little difference, at line level it's all about preserving the inserted signal without introducing funky reactive elements that cause time and frequency problems. It's also about protecting the small signal from environmental influences—RF in all it's forms and acoustic. Loudspeaker cables are both power level and signal level and are tackled very differently with impedance playing a much larger role. AC cable, well that's a bit tricky. It depends on so many factors that it's impossible to predict if a hi-fi power cable will even make a difference. The power grid in your area, the transformer feeding your house, the grounding of your home's grid, the noise on your lines, the ground relations of your gear; and on top of that you have the power supply of each component in your playback. The perfect power supply would not benefit from a super duper power cable.

But, since perfection moves from us at least proportional to our approach… the power cable proliferation of the last ten years. For Zu, we think containing the radiated field is essential, this takes a whole lot of conductor; a simple foil wrap ain't going to cut it. Zu also believes in keeping the ground circuits' impedance as low as possible. All this is a very brief overview focused on the fundamental reasons for fidelity preservation, electrodynamics. Chemistry and other branches of physics are also used by Zu to research, develop and finally market a good sounding cable, but way to much has been made of "conductor purity" simply to justify the stupidly high prices charged for patch cables.

PFO What about metals ...copper versus silver versus gold versus what? What about blends?

SC Guess I should have read a bit further, shootin' these questions as they come. Yeah, conductor makes a difference but it is a secondary concern. I don't care how awesome the parts are, the platform is the driving element. Companies selling bazillian-nines purity whatever are doing so because they ain't got anything else to sell you. "Treatments" I guess, but here again, chemistry must serve the electromagnetic/electrostatic model. Customers should buy cables based on how the stuff performs, nothing more. Make sure you have at least a 30-day window to return it for full refund. Listen, call it as you hear it, what is right for you might not be the thing for me.

PFO What about dielectrics... Teflon versus what?

SC Sure, a big secondary influence. All types of dielectric materials interact and "sound" differently. Silk, cotton, wax, PE, cross-linked PE, TFEP, PO, PU, PVC, and on and on and on and on (hey, isn't that a John Lydon song). Even in just the Teflon-type plastic there are hundreds of variants, with all sounding different. It's impossible to say really what is best. The reason some people love the sound of a little copper wire insulated in silk soaked in pure carnauba might not be because of the silk….

PFO What about no dielectric?

SC Like lightning without the lightning bolt then? Maybe we're talking about pure music here, where angles insert the stuff directly to your soul. Are you telling me somebody is marketing a "dielectric free" cable? The guy is likely very interesting at a party, but buying his product, don't do it man!

PFO What about measurements... what do they tell us? What do they not tell us?

SC Measures dramatically accelerate the research and development stage for those that have built a real knowledge base of factors and correlations. They are also necessary for proper quality control. Measures and the whole scientific procedure is a very complex undertaking, and very much worth the effort for the engineer. How measures relate to your buying decision, not really sure. Basic measures tell little about how the product will sound, only that it might fit an application. In the end it's about the sound, and Zu fully supports the ear/mind being the final arbiter of sonic pleasure.

PFO What about connectors... how important?

SC Yes, you need to hook stuff up, and yes, connectors can influence fidelity in significant ways. Zu is an anti-solder bunch. We use cold forging (high pressure crimp in the correct sort of way) anytime we possibly can. Very few of our cable products use solder; even our loudspeakers feature cold forged connections; the entire full range driver to input circuit for example. Banana's or copper cold forged spaces lugs? Spades every time.

PFO Why this geometry... ribbon, twisted, braded, spiraled...?

SC Hey, you forgot about Zu's B3! Geometry. Like mentioned above, the E&M model of the cable IS geometry. Everything else is second. Outside of the basic twisted Pair, Nikola Tesla is the guy when it came to E&M and the transmission of signal, power or both. Most cable formats can be traced back to Tesla; coax, including sectional forms, Litz, hyper Litz, ribbon…

PFO What about cryoing? What is going on with this? 

SC Very little original research has been carried out relative to diamagnetic materials and temperature. Most of it is specific to ferrous metals, working strength, structure…. The research that has taken place in the super low temp work relative to diamagnetic metals and E&M is behavior at these temps, super conductive work; Coopers pairs, tunneling, zero resistance. Zu is on the fence on cryo of audio cable.

PFO Why shielding? Why not shielding?

SC Make a cable that is as immune to outside RF while minimizing the fix's effect on the signal. It's a balancing act, like most things in life. Sure Tesla could have built you a listening room or home that was free from external RF, and gear that did not radiate RF, and a power distribution system that was free of degrading RF effects, but I don't think he's going to come back and make your obsessive dreams come true (you know he was an alien right, and teleported of the Earth). It's not a case of yes or no, it's balancing the thing.

PFO What about run-in? Why is/isn't it important?

SC A well aged cable simply sounds better. All cables, transmitting and receiving systems, signal, power level; there are a ton of variables to this question. It seems to relate primarily to the stressing of the insulators electron cloud orbitals and very little to do with the conductor. We have had some original work on the scheduled with Dr. Seoul at WSU for the last few years but have lacked time to carry it out. For five years now, Zu has been investigating the effects of signal and power on the varies cables in-house; and five years later we are still not prepared to release any data or findings. While our knowledge base on this has expanded, it has opened more doors that must be explored.

PFO What about lengths? Why are/aren't they important?

SC After the obvious, being able to make the connection, length should not be that big of an issue. If the cable has a major design flaw then maybe. Or, and I have seen this, the cable marketing company is reducing his stocking units, since they are outsourcing the thing, making the claim that a specific length sounds better to increase their bottom line. Generally shorter is better, but nearly all lengths used in home audio should be considered short.

PFO What is directionality?

SC Relating to burn-in and dielectric, there does seem to be a "direction" in any structure; all conductors we have messed with, from metals, to rocks exhibit directionality and signal fidelity. It means that nearly all cables will sound better in one direction than another. Some cables can be reversed, some can't.

PFO How did you get into this?

SC It seems all of us here at Zu have been "in to it" for as long as most can remember. Specific to cables, I picked up a pair of used Klipsch LaScala loudspeakers at the age of 14, worked my butt off trying to get them sounding just right, replacing caps, inductors, even bi-amping and line-level processing, eventually looking at wire and cable and my grandpa's stash of U.S. military silver and silver plated wire stock. U.S. military surplus, ah, nothing like digging though racks and racks of super cool, perfectly good junk!

PFO What is your fundamental design philosophy/goal?

SC Any device must serve the music, let it through—sincerity. No mumbo jumbo to cloud this up.

PFO Why these?

SC Because you must always approach music with an open mind, same for the application of theory to the physical. To question and doubt is essential for sincerity, and the occasional good idea. We try to keep the mental baggage to a minimum.

PFO How do you approach accomplishing those philosophies/goals?

SC Listen to a lot of real music, from anywhere, in any form…

PFO How successful do you feel you have been at achieving the goals that you have set for yourself?

SC We're a pretty happy bunch, love what we do and have a lot of happy Zu users. These are our primary indicators of success.

PFO How do you plan to push beyond what you have already accomplished?

SC Keep a clear head, work our fingers to the bone, obsess, try things, dream, live; and when looking at business we put ourselves in the shoes of our customers and let that guide our decisions.

PFO Where is this all heading?

SC Zu - A Revolution in American Hi-Fi. Okay, it's more like a reformation, but we think we can bring back the stereo as the most significant furnishing in the home, and we think we can make it sound better for less. Not just for the obsessed hi-fi, music lovin' freaks like Dave and Carol. Nope, we would like to make real hi-fi accessible for everybody that holds a job and contributes.

PFO Others that you admire?

SC Lars Nordlund.

Click here to read the other interviews in the series.