Benchmark Media Systems ADC1 USB

The ADC1 USB is a 2-channel 192-kHz 24-bit analog-to-digital audio converter with an unprecedented feature set. This converter was designed to consistently deliver reference quality conversion in 'real-world' conditions. It features Benchmark's jitter-immune UltraLock™(tm) clock system and an extraordinary analog front-end.

• Jitter-immune UltraLock™
The UltraLock™(tm) system delivers consistent, high-quality conversion even when slaved to a poor quality external clock. The performance of the ADC1 USB will not degrade when slaved to an external clock - a claim very few converters can make. Enjoy the convenience of a clock input that automatically recognizes AES/EBU, S/PDIF, Word Clock, or Super Clock sources - all with the unsurpassed jitter immunity of Benchmark's UltraLock™(tm) clock-isolation system.

• Benchmark's Precision Analog Circuitry
Benchmark has a long tradition of building ultra-high performance analog circuits that are designed for maximum transparency. The ADC1 USB extends this tradition by pushing performance to the limits of today's technology. The analog front-end delivers low-noise low-distortion high-bandwidth performance over a wide gain range (45dB). Precise gain and calibration controls allow for accurate channel matching. Capture exact imaging, difficult transients, and subtle details with stunning realism.

• Intelligent Meters
The nine-segment dual-range, digital LED meters enable high-precision level monitoring. Meter response times are matched to the response of the human eye so that every peak is clearly visible. All metering is fully-digital and is not subject to calibration errors. A peak hold function allows an infinite hold to verify that an over has not occurred. Dual ranges allow signal presence monitoring, or precise headroom indication. The meters even use an upsampling technique to detect and display inter-sample peak overloads. This upsampled metering warns of potential overloads that may not be detected by conventional digital meters.

• Flexible Digital Outputs
The ADC1 USB has a total of 5 digital outputs (1-XLR, 2-coax, 1-optical, and 1-USB). These can operate simultaneously at up to three independent sample rates. One of the coaxial outputs can be configured for 16-bit TPDF dithered output. This unique flexibility allows simultaneous recording to a CDR, while recording high-resolution to a digital recorder and a DAW. For example the CDR may operate at 44.1/16 while the DAW operates at 88.2/24 while the digital recorder operates at 192/24. Backup and/or reference recordings can be created with ease while high-resolution outputs are fed to primary recording devices. The optical output supports AES or ADAT formats at resolutions up to 192/24. In ADAT mode, high sample rates are supported using SMUX2 and SMUX4.

• Benchmark's AdvancedUSB
Benchmark's AdvancedUSB solution provides a bit-transparent computer interface that is capable of streaming at rates up to 96 kHz/24-bit without installing any drivers. This reduces CPU loading, eliminates driver compatibility issues, and greatly improves the reliability of the data transfer. Benchmark's unique driver-less AdvancedUSB(tm) solution is compatible with Mac OSX and Windows 2000, XP, and Vista. Benchmark's UltraLock™(tm) clock system insures the audio will never be contaminated with jitter-induced artifacts from a poor-quality computer-based clock. With the Benchmark ADC1, the performance of the USB interface matches the quality of the AES and ADAT interfaces. The convenience of a direct computer interface no longer comes with a performance penalty!

• Consistent Performance
Often specifications only indicate how a product will perform under the most optimal conditions. The ADC1 USB is designed to deliver consistent performance - even in adverse conditions. The ADC1 USB is fully specified at all gain settings, all sample rates, through all digital outputs, and even when locked to a high-jitter clock signal.

Analog Audio Inputs
• Number of Inputs (balanced): 2
• Connector: Gold-Pin Neutrik™ female XLR
• Impedance: 200 k Ω
• Sensitivity: -14dBu to +29 dBu (at 0 dBFS)

Clock Reference Input
• Format: Auto-detect AES/EBU, Word Clock, and Super Clock (256x)
• Impedance: 75 Ω
• Sensitivity: 150 mV AES, 200 mV Word Clock, 750 mV Super Clock
• Transformer Coupled: Yes
• DC Blocking Capacitors: Yes
• Transient and Over-Voltage Protection: Yes
• Jitter Attenuation Method: Benchmark UltraLock

Wordclock Reference Output
• Impedance: 75 Ω
• Level: 5 Vpp, 2.5 Vpp into 75 Ω
• Transformer Coupled: No
• DC Blocking Capacitors: No
• Transient and Over-Voltage Protection: Yes

Digital Audio Outputs
• Number of Digital Outputs: 1 XLR Main, 1 TOSLINK Main, 1 BNC Main, 1 BNC Aux, 1 USB
• Connectors: Gold-Pin Neutrik™ male XLR
• Number of Audio Channels: 2
• Main Output Word Length: 24 bits
• Main Output Sample Frequencies: 44.1, 48, 88.2, 176.4, or 192 kHz
• Aux Output Word Length: 16 or 24 bits
• Impedance: 110 Ω XLR, 75 Ω BNC
• Level: 4 Vpp into 100 Ω XLR, 1 Vpp into 75 Ω BNC
• Transformer Coupled: Yes
• DC Blocking Capacitors: Yes
• Transient and Over-Voltage Protection: Yes

Audio Performance
Fs = 44.1 to 192 kHz, 20 to 20 kHz BW, 1 kHz test tone, 0 dBFS = +24 dBu (unless noted)

• SNR - A-Weighted, 0 dBFS = +8 to +29 dBu: 121 dB
• SNR - Unweighted, 0 dBFS = +8 to +29 dBu: 119 dB
• SNR - A-Weighted at max gain, 0 dBFS = -14 dBu: 108 dB
• THD+N, 1 kHz at -1 dBFS: -102 dBFS, -101 dB, 0.00089%
• THD+N, 1 kHz at -3 dBFS: -107 dBFS, -104 dB, 0.00063%
• THD+N, 20 to 20 kHz test tone at -3 dBFS: -106 dBFS, -103 dB, 0.00071%

• Frequency Response at 192 kHz Sample Rate: -3 dB, +0 dB, 2 Hz to 92 kHz; +/- 0.01 dB, 20 Hz to 20 kHz; -0.06 dB at 10 Hz; -0.01 dB at 20 Hz; -0.00 dB at 20 kHz; -0.18 dB at 88 kHz; -3 dB at 92 kHz; -100 dB at 108 kHz

• Frequency Response at 96 kHz Sample Rate: -3 dB, +0 dB, 1 Hz to 46 kHz; +/- 0.01 dB, 20 Hz to 20 kHz; -0.06 dB at 10 Hz -0.01 dB at 20 Hz; -0.00 dB at 20 kHz -0.10 dB at 44 kHz; -3 dB at 46 kHz -108 dB at 54 kHz

• Frequency Response at 48 kHz Sample Rate: 3 dB, +0 dB, 1 Hz to 23 kHz; +/- 0.01 dB, 20 Hz to 20 kHz; -0.06 dB at 10 Hz; -0.01 dB at 20 Hz; -0.00 dB at 20 kHz; -0.10 dB at 22 kHz; -3 dB at 23 kHz; -110 dB at 27 kHz

• Passband Ripple: +/- 0.008 dB
• Crosstalk: -105 dB at 20 kHz; -130 dB at 1 kHz; -130 dB at 1 kHz; -200 dB at 20 Hz

• Jitter Tolerance (With no Measurable Change in Performance): >12.75 UI sine, 100 Hz to 10 kHz; >3.5 UI sine at 20 kHz; >1.2 UI sine at 40 kHz; >0.4 UI sine at 80 kHz; >0.29 UI sine at 90 kHz; >0.25 UI sine above 160 kHz

• Maximum Amplitude of Jitter Induced Sidebands: < -134 dB with 10 kHz 0 dBFS test tone, 12.75 UI sinusoidal jitter at 1 kHz (measurement limit)

• Maximum Amplitude of Spurious Tones with 0 dBFS test signal: -130 dBFS
• Maximum Amplitude of Idle Tones: -145 dBFS
• Maximum Amplitude of AC line related Hum & Noise: -130 dBFS
• Interchannel Differential Phase (Stereo Pair): +/- 0.5 degrees at 20 kHz
• Interchannel Differential Phase (Between ADC1 Units): +/- 0.5 degrees at 20 kHz
• Maximum Lock Time after Fs change: < 1 s for frequency lock, < 5 s for phase lock
• Mute on Sample Rate Change: Yes
• Mute on Loss of External Clock: No
• Mute on Lock Error: No
• Mute on Receive Error: No
• Soft Mute Ramp Up/Down Time: 10 ms

Group Delay (Latency)
• Delay (Analog Input to Digital Output): 1.20 ms at 44.1 kHz, 1.09 ms at 48 kHz, 0.75 ms at 88.2 kHz, 0.67 ms at 96 kHz, 0.63 ms at 176.4 kHz, 0.59 ms at 192 kHz

LED Status Indicators
• LED Location: Front Panel
• Mode Indicators: 9 green
• Meter: 14 green, 2 yellow, 2 red

AC Power Requirements
• 14 green, 2 yellow, 2 red 110 V setting - 95 V min 140 V max, 220 V setting - 190 V min, 285 V max
• Frequency: 50-60 Hz
• Power: 16 Watts Idle, 16 Watts Typical Program, 20 Watts Maximum
• Fuses: 5 x 20 mm (2 required), 110 V setting - 0.5 A 250 V Slo-Blo® Type, 220 V setting - 0.5 A 250 V Slo-Blo® Type

Dimensions and Weight
• Form Factor: 1/2 Rack Wide, 1 RU High
• Depth behind front panel: 8.5" (216 mm)
• Overall depth including connectors without power cord or BNC-to-RCA adapter: 9.33" (237 mm)
• Width: 9.5" (249 mm)
• Height: 1.725" (44.5 mm)
• Weight ADC1 only: 3.6 lb, ADC1 with power cord, 3 BNC-to-RCA adapters, extra fuses, and manual: 4.9 lb.
• Rack mount kit (blank panel, junction block, and rack-mount screws) 0.32 lb.
• Shipping weight: 7 lb.