Associated Equipment:
Digital Front End
Power Conditioning
Z-Cable’s Z-Sleeve Standard, Ref1, and Ultra1 Power and Signal Line Conditioner - a Follow-up

Synergy for Cable Technology

Michael Girardi

August 2004

What’s a Z-Sleeve?

As stated on the Z-Cable website:

“The Z-SLEEVE is a power and signal line conditioner that fits over the outside of the cable. The cable slips through it. The cable does not plug into it. As such, it is passive in its design, and does not interfere with the circuit of the audio or video system. It also does not distort the signal as other "in-circuit" signal line conditioners can. It is not a signal filter that truncates the upper frequencies range of the signal to "cut out" EMI or RFI, by running the signal through some network circuitry”.

“There are really three different technologies incorporated into the design of ZCable's Z-SLEEVES:

1. Zero Gauss Chamber - A Zero Gauss Chamber (ZGC) is normally used by electrical engineers or technicians for calibration of Gauss Meters and other devices that measure magnetic fields. It creates a workspace internal to the chamber where there is extremely low magnetic fields.

2. ERS material - ERS material, from Stillpoints, is designed to absorb, diffuse, and reflect EMI/RFI.

The use of the ERS material increases the storage capacity of the Z-SLEEVE so that it holds more magnetism. The ZGC design increases the ERS's ability to collect EMI/RFI.

3. Sleeve Harmonics - by putting any conductive sleeve around a signal or power cord, you will change the tonal balance and tonal harmonics of the cable. Sleeve ratios of diameter, length, and thickness and testing of metals which compose the
the sleeve were optimized for frequency and tonal balance”.

Each Z-Sleeve consists of three different non-magnetic metal shields utilizing a proprietary sequence of ERS layers and metal shields resulting a linear frequency response ZGC.

Though designed originally in conjunction with Z-Cable’s own line of interconnects, speaker cables, and AC cords, the Z-SLEEVES can be used with any cables. The only limitation might be some anaconda-like cables that may be too thick to slide through the Z-SLEEVE.

Can Z-Sleeves Benefit an all Digital System?

My reviewing system includes the Audio Note CDT-2 transport with Audiocom Superclock and Power Supply, Tact RCS2.0S Room Correction preamplifier, Tact Millenium MKII, Talon Audio Khorus X MKII speakers, Stealth Hybrid MLT speaker cables, Stealth Audio Varidig cryogenically treated AES/EBU digital interconnects, Still Points and Risers, and Foundation Research LC1 powerline conditioner/cords on front end components and FR LC2 on the Tact Audio Millennium.

Over the past two years I’ve replaced power cords and then recently modded my Audio Note transport with the Audiocom Super Clock and Power Supply with the goal of reducing the overall system noise floor. After installing Still Points ERS cloth in various places in the chassis of my main system components, I didn’t think there was much improvement to be made. I was so wrong …

Initially Mark Hampton of ZCable sent me one Standard Z-Sleeve to install between the AN CDT-2 transport and TacT RCS2.0S. Using Pitch and Davis, Feast, (Alert Z2-81031) as my reference CD, I immediately noticed improvements in image focus/depth, soundstaging and separation of instruments. Allowing for a 24 hour system break-in resulted in a further digital glare reduction, enhanced detail and improved signal coherency.
I later replaced the Standard Z-Sleeve with a Ref1 and then an Ultra1 Z-Sleeve. The same benefits were heard only the overall improvement was enhanced at least 5X and 10x respectively. As I installed a pair of Z-Sleeve Ref1 on my Stealth MLT speaker cables, I started to notice the bass pitch definition and speed improved allowing me to better heard between two successive bass notes that were previously blurred together in cut 12 on Pitch and Davis, Feast, (Alert Z2-81031). In summary, as more Sleeves were installed in my system, their affects were repeatable and additive.

The Khorus X MKII integrates well in my room seldom localizing itself but after installing Z-Sleeves on my digital and speaker cables … its magic … the Talons completely disappear now. With the pair of Z-Sleeves installed on Stealth MLT speaker cables, the micro/macro dynamics were better delineated communicating the emotion of the music. Music notes start … notes stop while immersed in deep black background.


I whole heartily agree with Paul Szabady’s review of the Standard Z-Sleeve (click here to see Paul's review).

In an audio and video system, “the issue is both the EMI field external to the cable, as well as the EMI generated by the cable.” In an all-digital system such as mine, low current is carried along digital interconnects, which tends make this type of system more susceptible to air borne and cable emitting EMI/RFI pollution. ZCable delivers the technology without adding or subtracting from the original signal which few line conditioners could ever achieve.

In order to complete the path to audio nirvana, the audiophile must mechanically isolate components, eliminate jitter, and lastly properly eliminate EMI/RFI pollution. The technology implemented by ZCable in treating EMI/RFI grunge is unmatched by any tweaks I’ve tried in the past (all having both positive and negative effects). The overall improvement is equal to a major component upgrade … IMHO this is a NO-BRAINER.


Passive Line Conditioner cylinder incorporating ERS cloth with a length of 8” and an internal diameter of 1 1/8”.
Pricing available direct from Z-Cable:
Standard V1, 8 layers of ERS cloth, $99 each
Ref1, 26 layers of ERS cloth, $199 each
Ultra1, 36 layers of ERS cloth, $299 each

7114 E. Douglas Ave.
Wichita, KS 67206 t
Phone: (316) 946-3762