Talk to an audio consultant

BENCHMARK - DAC1 Digital to Analog Converter

Benchmark DAC1 2-Channel 24bit/192kHz D/A Converter

Benchmark Media's DAC1 gets Stereophile 'Product of the Year' -- 2004 Editor's Choice Award Winner

The Benchmark DAC1 is a two-channel, 24-bit/192-kHz Digital-to-Analog audio converter. The DAC1 is perhaps one of the more significant recent advances in digital audio conversion technology. The DAC1 provides some of the finest analog conversion through 192-kHz, and will play back 192-kHz with a 55-kHz analog bandwidth. The performance of the DAC1 is unrivaled. THD+N is an astonishing low -106 dB (0.0005%) measured at 0 dBFS, at any playback frequency, at any sample rate, with any degree of input jitter, and it just gets better from there.

"The Benchmark's measured performance is at least as good as, if not better than, the best high-end designs. Its use of a high-performance sample-rate converter chip ahead of its DAC chip means that its rejection of word-clock jitter is about as good as it gets. The DAC1 has two high-current headphone jacks. You can't find much more in the way of a high-end audio bargain than the Benchmark DAC1!"
- Stereophile, 2004 Editor's Choice Award

The DAC1 is a reference-quality, 2-channel 192k/24-bit audio digital-to-analog converter featuring Benchmark’s UltraLock™ technology. The DAC1 is designed for maximum transparency and is well suited for critical playback in studio control rooms and in mastering rooms. A compact and rugged enclosure makes the DAC1 an excellent choice for location recording, broadcast facilities, and mobile trucks. The internal power supply supports all international voltages and has generous margins for over and under voltage conditions.

Two ¼” headphone jacks are driven with Benchmark’s new HPA2™ headphone amplifier. The HPA2™ is a highcurrent amplifier that is capable of driving a wide variety of headphone loads while achieving less than 0.0003% distortion under load.

The gain control sets the output level of the headphone jacks. It can also be used to control the output level of the balanced XLR and unbalanced RCA analog outputs. A rear-panel switch selects Variable or Calibrated output levels.

The DAC1 is designed to interface directly to power amps and powered studio monitors in order to provide the cleanest and shortest path from digital to monitor output. 10, 20, and 30 dB pads are provided for interfacing to studio monitors having high input sensitivity.

Three digital inputs (balanced XLR, BNC with RCA adapter, and optical) are provided and are selected from the front panel. All inputs accept either professional or consumer formats.

The Benchmark UltraLock™ system is 100% jitter immune. The D/A conversion clock is totally isolated from the AES/EBU digital audio clocks in a topology that outperforms two-stage PLL designs. In fact, no jitter-induced artifacts can be detected using an Audio Precision System 2 Cascade test set. Measurement limits include detection of artifacts as low as -140 dBFS, application of jitter amplitudes as high as 12.75 unit intervals (UI) and application of jitter over a frequency range of 2 Hz to 200 kHz. Any AES/EBU signal that can be decoded by the AES/EBU receiver will be reproduced without the addition of any measurable jitter artifacts. In addition, the receiver IC has been selected for its ability to decode AES/EBU signals in the presence of very high levels of jitter.

The DAC1 is designed to perform gracefully in the presence of errors and interruptions at the digital audio inputs. A soft mute circuit eliminates pops when a digital signal is applied. Power management circuitry controls the muting and resetting of all digital circuits upon removal and application of power. Audio is present at the outputs only 60 ms after applying a digital input signal and only 500 ms after applying power to the unit. The DAC1 is designed to avoid all unnecessary mute scenarios. Muting is only enabled upon loss of power, or when digital transmission errors occur. The DAC1 does not mute when the input data is all zeros. Consequently, no audio is lost when an audio transient follows full silence. Furthermore, the DAC1 SNR specifications represent the true system performance, not just the performance of an output mute circuit.

The DAC1 will operate even when sample rate status bits are set incorrectly. Sample rate is determined by measuring the incoming signal. Lack of sample rate status bits or incorrectly set status bits will not cause loss of audio.

The DAC1 is phase accurate between channels at all sample rates, and is phase accurate between other DAC1 boxes at sample rates up to 110 kHz. A fully digital de-emphasis circuit supports 44.1, 48, 88.2 and 96-kHz sample rates and is automatically enabled in response to the pre-emphasis status bits of consumer format digital signals.

NOTE: Rack Mount version requires special Benchmark Rack Mount kit to fit in a standard 19" width rack.

FEATURE SUMMARY:
* XLR balanced, BNC coaxial, and TOSLINK optical digital inputs – front-panel switch selectable
* High level, +4 dBu balanced analog outputs, +29 dBu maximum output level
* Jumper-selected 10, 20, or 30 dB pads on balanced outputs
* -10 dBV unbalanced outputs, +13.5 dBu maximum output level, factory set to +2vRMS @ 0dBFS (8.2 dBu)
* Two HPA2™ high-current, high-output ¼” headphone jacks
* Front-panel knob controls all analog outputs or just the headphone outputs (selected with rear-panel switch)
* Analog output mute function on rear-panel switch
* Preset output levels use multi-turn trimmers – one 10-turn trimmer per output, 20 dB Range, 2 dB/turn
* Total jitter immunity with Benchmark, phase-accurate UltraLock™ technology
* Two Error LED’s, (no digital input, non-PCM digital input)
* Power Indicator LED
* THD+N = -107 dB, 0.00045% @ -3 dBFS input, -105 dB, 0.00056% @ 0 dBFS input
* Automatic de-emphasis in consumer mode at 44.1, 48, 88.2, or 96 kHz when pre-emphasis bit is set
* Reliable and consistent performance under all operating conditions
* 115 V, 230 V, 50-60 Hz international power supply with very wide operating range
* Low radiation toroidal power transformer significantly reduces hum and line related interference
* Low power consumption (8 Watts typical program, 16 Watts peak)
* Meets FCC Class B and CE emissions requirements

AUDIO PERFORMANCE SPECS:
Fs = 44.1 to 96 kHz, 20 to 20 kHz BW, 1 kHz test tone, 0 dBFS = +24 dBu (unless noted):
SNR – A-Weighted, (0 dBFS = +20 to +29 dBu): 116 dB
SNR – Unweighted, (0 dBFS = +20 to +29 dBu): 114 dB
SNR – A-Weighted at low gain, (0 dBFS = +9 to +18 dBu): 114 dB
THD+N, 1 kHz at 0 dBFS: -105 dBFS, -105 dB, 0.00056%
THD+N, 1 kHz at –1 dBFS: -107 dBFS, -106 dB, 0.00050%
THD+N, 1 kHz at –3 dBFS: -110 dBFS, -107 dB, 0.00045%
THD+N, 20 to 20 kHz test tone at –3 dBFS: -110 dBFS, -107 dB, 0.00045%
Frequency Response at Fs=48 kHz: +/- 0.1 dB (20 to 20 kHz)
 -0.02 dB at 10 Hz
 -0.20 dB at 20 kHz
Frequency Response at Fs=96 kHz: +/- 0.1 dB (20 to 20 kHz)
 -0.02 dB at 10 Hz
 -0.20 dB at 20 kHz
 -0.85 dB at 40 kHz
 -2.5 dB at 45 kHz
Crosstalk: -100 dB at 20 kHz
 -125 dB at 1 kHz
 -130 dB at 20 Hz
Maximum Amplitude of Jitter Induced Sidebands: < -141 dB
(10 kHz 0 dBFS test tone, 12.75 UI sinusoidal jitter at 1 kHz)
Maximum Amplitude of Spurious Tones with 0 dBFS test signal: < -126 dB
Maximum Amplitude of Idle Tones: < -128 dB
Maximum Amplitude of AC line related Hum & Noise: < -126 dB
Interchannel Differential Phase (Stereo Pair): +/- 0.5 degrees at 20 kHz – any sample rate
Interchannel Differential Phase (Between DAC1 Units Fs<110): +/- 0.5 degrees at 20 kHz – Fs < 110 kHz
Interchannel Differential Phase (Between DAC1 Units Fs>110): +/- 4.1 degrees at 20 kHz – Fs > 110 kHz
Delay (Digital Input to Analog Output): 1.01 ms + (48/Fs)
 2.10 ms at 44.1 kHz
 2.01 ms at 48 kHz
 1.55 ms at 88.2 kHz
 1.51 ms at 96 kHz
 1.28 ms at 176.4 kHz
 1.26 ms at 192 kHz
Maximum Lock Time – after Fs change: 100 ms
Soft Mute Ramp Up/Down Time: 10 ms
Mute on Receive Error: Yes
Mute on Lock Error: Yes
Mute on Idle Channel: No
50/15 us De-Emphasis Enable: Automatic in Consumer Mode
De-Emphasis Method: Digital IIR
De-Emphasis Supported at: Fs = 32, 44.1, 48, and 96 kHz

GROUP DELAY (LATENCY):
Delay from digital input to analog output is a function of sample rate:
 2.72 ms at 28 kHz
 2.51 ms at 32 kHz
 2.10 ms at 44.1 kHz
 2.01 ms at 48 kHz
 1.55 ms at 88.2 kHz
 1.51 ms at 96 kHz
 1.28 ms at 176.4 kHz
 1.26 ms at 192 kHz
The delay can be calculated using the following formula:
Delay = 1.01 ms + (48/Fs)
Where Fs = the sample rate in Hz.
LED STATUS INDICATORS:
LED Location: Front Panel
Power: (AC power is connected and +5 V supply is operating) 1 (Blue)
Error: (Error on the active digital input) 1 (Red)
Non PCM: (Non-compatible digital audio format on active input) 1 (Red)

AC POWER REQUIREMENTS:
50-60 Hz
8 Watts Idle
8 Watts Typical Program
16 Watts Maximum
Fuses (2 required) – 5 x 20 mm
100 V to 130 VAC operation – 0.5 Amp 250 V Slo-Blo® Type
200 V to 260 VAC operation – 0.25 Amp 250 V Slo-Blo® Type
Input Operating Voltage Range – VAC RMS
110 V setting – 90 V min, 140 V max
220 V setting – 175 V min, 285 V max

DIMENSIONS:
½ Rack Wide, 1 RU High
8.5” (216 mm) Depth behind front panel
9.33” (237 mm) Overall depth including connectors but without power cord or BNC-to-RCA adapter.
9.5” (249 mm) Wide
1.725” (44.5 mm) High

WEIGHT:
DAC1 only: 3.5 lb.
DAC1 with power cord, BNC-to-RCA adapter, and manual: 4.5 lb.
Rack mount kit (blank panel, junction block, and rack-mount screws): 0.32 lb.
Shipping weight: 7 lb.