This review page is supported in part by the sponsors whose ad banners are displayed below


Reviewer: Srajan Ebaen
Financial Interests: click here
Source: Ancient Audio Lektor Prime, Raysonic Audio CD228, Apple iMac 1TB with AIFF files up to 24/192, Weiss DAC2, iPod Classic 160GB, Sieben Technology dock
Preamp/Integrated: Esoteric C-03 (transistor), Bent Audio Tap-X (AVC passive), ModWright DM 36.5 (tube)
Amplifier: FirstWatt F5 & J2, ModWright KWA-100 SE, Trafomatic Audio Kaivalya, Octave Audio MRE-130 with SSB, Yamamoto A-09S
Speakers: ASI Tango R, Zu Essence, Boenicke SLS
Headphones: ALO Audio recabled Sennheiser HD800, beyerdynamic T1 and AKG K-702; stock audio-technica W5000; stock Grado PS-1000; HifiMan HE5LE with optional silver wiring and grill mod
Headphone amps: Trafomatic Audio Head One; Woo Audio Model 5; Burson Audio HA-160; Meier Audio Corda Concerto
Cables: Complete loom of ASI Liveline, Furutech GT2 and WireWorld Starlight 5² USB A-to-mini-B cables [on loan], LaCie and Entreq Firewire 800 cables, Black Cat Cable Veloce S/PDIF cable [on loan]
Stands: 2 x ASI HeartSong 3-tier, 2 x ASI HeartSong amp stand
Powerline conditioning: 1 x Walker Audio Velocitor S, 1 x Furutech RTP-6
Sundry accessories: Furutech RD-2 CD demagnetizer; Nanotech Nespa Pro; extensive use of Acoustic System Resonators, noise filters and phase inverters, Advanced Acoustics Orbis Wall & Corner units
Room size: 5m x 11.5m W x D, 2.6m ceiling with exposed wooden cross beams every 60cm, plaster over brick walls, suspended wood floor with Tatami-type throw rugs. The listening space opens into the second storey via a staircase and the kitchen/dining room are behind the main listening chair. The latter is thus positioned in the middle of this open floor plan without the usual nearby back wall.
Review Component Retail: $2.500
A YouTube interview with Antelope Audio founder Igor Levin in parts I & II covers his views on how the randomization of jitter helps create a more analog sound; and how adding strategic jitter does, similar to dither, break up modulation patterns to increase the linearity of D/A conversion chips. Mind you, this occurs after the signal has first been stripped of jitter and reclocked with a temperature-controlled master clock oscillator plus 4th-generation 64-bit math. Antelope refers to its proprietary technique as acoustically focused clocking and jitter management.

click on image for full-size photo of Zodiac +


One might—very roughly—approximate jitter with harmonic distortion. It's not necessarily lowest THD that wins but exactly how unavoidable remaining total harmonic distortion is distributed.

The pro-audio Antelope company is best known for its master clocks including an atomic Rubidium model. How would technology derivative from their Trinity master clock combine with BurrBrown D/A conversion? How about auto-detect source switching, mono summing, analog level control, two headphone outputs with dedicated attenuator and trimmable XLR analog outputs on the back? What of ascending single-box functionality from Zodiac (96kHz USB) to Zodiac Plus (192kHz USB) and Zodiac Gold (384kHz USB)? In the pro sector, Benchmark, dCS, EMM Labs and Weiss all have gone audiophile before. Should one spot a crossover trend?


The middle of the range Zodiac Plus model offers a plethora of sockets including analog RCA inputs and RCA/XLR outputs. For digital there are twin coax, twin Toslink and one each mini USB, XLR and BNC word clock in; and XLR and twin coax out. There's also an 18V DC input for the external universal PSU (100-240VAC in, 18VDC/10w out). Dimensions of 4.4 x 6.5 x 7.5" HxWxD (112 x 165 x 190mm) are compact, 4.4lb (2kg) are light to be attractive for desk-top use too. Gold-plated circuit boards for analog and digital are separate and the attenuators (main and headphones) are in the analog domain. Key specs are 129dB of dynamic range, THD+N of 0.0004% and clock stability of <±0.02ppm @ 64.5°C.


As an asynchronous USB 2.0 Hi-Speed device (480Mbits), the Zodiac+ contains firmware (drivers) for which occasional updates might become available. To check the current software version, disconnect the DAC from its PSU for 3 seconds, then hold the source button whilst reconnecting the power supply. The display will now show the software version for 5 seconds. If software updates exist, download them from Antelope's website. With the Zodiac+ in standby connected to the PC via USB, press the mute button until the display shows Ldr (loader mode). Now double-click the downloaded file and follow the instructions. The 2-phase installation usually takes from 2 to 5 minutes. Upon completion, the Zodiac+ automatically exits loader mode. It must now be rebooted by disconnecting it again from its power supply for at least 3 seconds before restarting it.


Features at a glance:

1: Signal lock indicator
2: Word clock indicator
3: Mono indicator
4: Main volume with a level display from -90 to 0dB
5: Multi-function display for sample rate, main volume, input type and USB mode (UF1, UH1)
6: Headphone level
7: Standby/power toggle
8: Power indicator - standby dim, power bright
9: Source mode
10: Mono mode
11: Mute
12: Paralleled headphone outputs

13: DC power connection
14: ¼" TRS balanced analog inputs
15: RCA unbalanced analog inputs
16: Trim pots for output XLRS (+4 to +22dBu)
17: Balanced XLR analog outputs
18: Unbalanced RCA analog outputs
19: BNC word clock input
20: Toslink inputs
21: 75-ohm S/PDIF inputs
22: Hi-Speed USB 2.0 input on mini B type*
23: 110-ohm AES/EBU input
24: Dejittered 110-ohm AES/EBU output
25: Dejittered 75-ohm S/PDIF coaxial outputs

________________________

* Audiophile USB cables with mini B plug aren't exactly common yet but WireWorld has two models, the Ultraviolet and Starlight. The latter is a 24-gauge silver-clad OFC copper flat design available in 0.5m and 1m lengths with mini B plug (otherwise up to 7 meters with standard B plugs).

Furutech has their GT2 with silver-plated Alpha-treated OCC conductors, "special-grade high-density polyethylene dielectric, a tri-layer shielded construction for improved noise insulation and Furutech-engineered 24k gold-plated USB series connectors."


For 2.500 pro-audio smackers, the Zodiac Plus offers features which in equivalent audiophile currency buy considerably less from established USB DAC leaders like Ayre and Wavelength. While the Wyred4Sound DAC2 does meet the Antelope nearly head on, it lacks its headphone sockets, oven-controlled clock, mono function, analog volume control, word-clock and analog inputs.

It retaliates however with remote control and a $1.000 savings. Where Wyred's 24/192 USB interface and firmware were outsourced, Antelope's was developed in-house. Ditto for their 64-bit clock-control algorithms. Though it should be obvious, it bears repeating - analog-domain volume allows the Zodiac Plus to become a miniature preamp no strings attached. It even accepts one non-digital source. That's another potential cost savings and also attractive downsizing proposition. Compared to Antelope, most prior pro-gone-consumer companies like dCS, Meitner and Weiss have positioned themselves on rather pricier turf. This wins the newcomer a clear advantage in today's economic climate. If white is the new black, value is the new hip. From that perspective and despite being black, the Zodiac+ is a very hip proposition. As to its heart beat—the proprietary jitter management algorithm—Leizer Benvenishty of Antelope's sales department acknowledged candidly that comprehending it fully exceeds his grasp and more to the point, that designer Igor Levin wouldn't share word one with the press. Without getting hung up on buzz words like "acoustically focused clocking" (they do have to call it something; and yes their site is full of marketing somethings), we'll leave speculation to others and focus on our audiophile prerogative instead: what does it sounds like?

Antelope at 2010 Frankfurter Musik Messe

It's presumptuous of course to assume that the Zodiac range was launched just for audiophiles. There aren't enough of our kind left. However, Antelope's website does make a tie-in of background imagery with each model - a DJ or lap-top headphone listener for the basic Zodiac; a mixing console for the Zodiac+; and a Classé/B&W system for the Gold. What turns a Plus into a Gold? "The standard Zodiac does up to 96Khz via optical and USB and 192Khz via S/PDIF. The Gold does up to 384Khz via USB and has a stepped attenuator with gold relays and a cool remote control with soft and full mute function. BurrBrown's 1792-A chip is applied across all three models and the Gold's circuitry differs from the Plus primarily in the analogue domain." To source software that was actually recorded at 384kHz and is made available to consumers at that data density seems quite futuristic but remote control and purist attenuation certainly do cater to audiophiles. For the Gold, there's also an optional "heavy duty" power supply to upgrade the laptop-type SMPS. (Here's a company sheet with more Antelope talk about how these three models differ.)

Antelope's proprietary async USB implementation runs a buffer and field-programmable gate array to apply signal dejittering to byte-by-byte data extraction from the buffer. It runs both Windows and OS firmware for bidirectional communication protocols and special device drivers for USB 2.0 high speed. Actual data processing past establishing the data comm link with the host computer of course remains identical between different operating systems. As Igor Levin put it, "the jitter management module derives the sample rate via a DSP process that is largely insensitive to the USB packet arrival jitter. The reconstructed audio clock is acoustically pleasing and does not contain any measurable jitter products above 10Hz." For further sound enhancements, one can reference the Zodiac+ to Antelope's 10M+ Trinity/OCX master clock via the word-clock input. This supposedly results in "dramatically opening up the stereo image to reveal more details in three-dimensional space."


Enlarge!