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Reviewer: Srajan Ebaen
Financial Interests: click
Source: 27" iMac with 3.4GHz quad-core Intel Core i7, 16GB 1.333MHz RAM, 2TB hard disc, 256GB SSD drive, ADM Radeon HD 6970M with 2GB of GDDR5 memory, PureMusic 1.82 in hybrid memory play with pre-allocated RAM and AIFF files up to 24/192; Antelope Audio Zodiac Gold/Voltikus, April Music Eximus DP1, April Music U3 [on loan], Esoteric/APL Hifi UX1/NWO-M, Auralic ARK MX+ [on loan]
Preamp/Integrated: ModWright LS-100 with Synergy Hifi tubes, Esoteric C-03, Bent Audio Tap-X
Amplifier: FirstWatt S2 [on loan], ModWright KWA 100-SE, Trafomatic Audio Kaivalya
Speakers: Aries Cerat Gladius [on extended loan]
Cables: Complete loom of Zu Audio Event, Entreq USB cables
Stands: 2 x ASI HeartSong 3-tier, 2 x ASI HeartSong amp stand
Powerline conditioning: 1 x GigaWatt PF2, 1 x Furutech RTP-6
Sundry accessories: Extensive use of Acoustic System Resonators, noise filters and phase inverters
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: $479 forUD384, $189 for U Power
Christine Wu, KingRex: "I don't know whether you already installed the UD384 drivers. Here is the procedure. 1. Charge the U Power as it should be in low-power mode from shipping. 2. Connect the UD384's USB port directly to the motherboard of your PC and make sure it supports USB2.0. 3. Please find the white plastic USB flash card which installs our user manual, driver, firmware, firmware update DFU tool and Mac DFU tool ( Requirements are that the CPU must be above dual core. Windows XP/ Vista/ Win 7 require the driver install. Mac OS 10.5 - 10.7 enjoy direct support so no driver is necessary.

"4. Suggested media player plug-ins: Windows XP - foobar 2000 + ASIO4ALL; Windows Vista/ Win 7- foobar 2000+WASAPI; MAC - iTunes + Pure Music or Amarra. Please note that the UD384 cannot accept 352.8kHz playback. We suggest you try 24/192 first. We are working with to get native 32bit/384kHz playback. I will keep you posted.

"If possible please also audition the UD384 with your floorstanding speaker system. For our internal tests we used the UD384 in our big system. The performance over our PMC PB1 was very good and we also took the device to local dealers who used Tannoy DC10T and A.D.A.M. Alpha speakers. Those auditions went very well too."

By now you'll have divined the device's intended application. But there's a wrinkle. The async UD384 sports a coaxial S/PDIF output and analog RCAs. Unlike April Music's U3, the two Audiophilleos or M2Tech's hiFace, it works as both USB-to-S/PDIF converter just in the digital domain; or as a complete if petite DAC with USB input. The digital output couples to a PE65612NL pulse transformer, incoming data are reclocked with a KingRex-branded 12MHz 1ppm master clock. The converter chip's identity has been erased. The U Power is an optional battery supply to upgrade standard 7.5V/250mA SMPS wall warts. It runs off two jacketed Sanyo Li-ion batteries for 2600mA/hr of auxiliary power. Charging occurs via included wall wart. When the chg/dc-out switch is set to the latter, charging disconnects supply from wall to eliminate AC noise. The UD384 supports all common sampling rates from 44.1kHz to 384kHz (the latter only via USB and not through the S/PDIF socket) but not 352.8kHz. Word lengths may be 16, 24 and 32 bits. The size of the oval aluminum extrusions is 110 x 82 x 24mm. A one-foot umbilical connects the two.