BENCHMARK
DAC1 STEREO 24/192 D/A CONVERTER

FEATURES:

• 2-channel, 24bit D-to-A conversion
• 192-kHz playback with 55 kHz analog bandwidth
• THD+N = -106 dB (0.0005%) measured at -0 dBFS, any sample rate, any test frequency, with any degree of input jitter
• 116 dB signal-to-noise ratio @48 kHz, A weighted
• AES/EBU (XLR & Coax) and S/PDIF (XLR, Coax, & Toslink) inputs
• Digital input source-selection switch
• Balanced, low-Z XLR outputs
• +29 dBu output level capability
• Unbalanced RCA outputs
• Variable or preset output level controls, switch selectable
• Direct connection to powered monitors
• Built-in Benchmark HPA-2, a high-output, ultra-clean headphone amplifier with dual outputs jacks
• Jitter immunity via UltraLock™ technology
• Phase Accurate D-to-A conversion across any number of channels
• 1 power, 2 error indicating LEDs
• Internal low-radiation toroidal power supply
• International 115-230 input voltage range
• Automatic De-emphasis for 44.1, 48, and 88.2 when Pre-emphasis bit is set
• 1/2 wide, 1RU chassis
• Rack mount kit available

The DAC1 is a two-channel, 24-bit 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 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.

Listening to audio from the DAC1 is an amazing experience. The distortion free output is so pristine it truly feels as though someone has finally lifted the curtain. Now you can hear detail that was previously masked by jitter induced artifacts and distortion. If it was an exceptional recording, you'll hear it, if it wasn't, you'll hear that as well.

Many DACs derive their system clock directly from the AES receiver making them very susceptible to jitter. These DACs can rarely achieve their rated performance in real world applications. By contrast, the DAC1 takes full advantage of our jitter free UltraLock™ technology. On the test bench, or at the end of 1000' of cable, the DAC1's performance is the same.

Additional features include auto-processing of pre-emphasized digital audio and our latest HPA-2 headphone amplifier technology. This technology features distortion levels of 0.0003% under load. The audio output levels may be controlled from the front panel by the same gain control that feeds the headphone amplifier or it may be preset to a precise level with multi-turn trims. The preset gain range is +10 dBu to +30 dBu at 0 dBFS. The DAC1 has built-in international 115/230 volt power.

The DAC1 is essential equipment for mastering studios; high quality recording studios, high-end home audio systems, or anywhere un-colored digital playback is demanded. 

This following graph is a look at the Eye pattern for 1000' of Belden MediaTwist¨ Cat 5e (11872A) - Green) and 1000' of General Cable Co. Cat 5e (Cat # 2133458H) - Yellow, along with the minimum signal eye pattern of the DAC1 - Blue.  Also included in this graph is the normal AES/EBU four volt output level found in normal professional digital audio equipment - Cyan.  The red "box" is the minimum tracking recommendation for a digital audio receiver as specified by the Audio Engineering Society.  As can be seen the DAC1 easily operates with total freedom from jitter at the end of a 1000' length of CAT5e data cable.

The last graph shows the output of the DAC1 having been fed 12.75 unit intervals of jitter.  Since jitter creates double sideband modulation products from the "carrier", in this case a 10 kHz audio tone, and the jitter frequency is 5-kHz, jitter induced sidebands of 5 and 15-kHz should be seen if jitter makes it to the DAC decoder chip.  The complete absence of these 5-kHz sidebands shows the power of UltraLock™ in providing total freedom from jitter induced audio products within the DAC1.

John Watkinson, is the author of the book "The Art of Digital Audio".  In the July/August 2002 edition of resolution, a new audio magazine from the UK, he wrote an article entitled The cable snake in a regular column feature known as "slaying dragons".  In that article he said "...On the other hand, if the DAC has not been properly engineered, changing the cable could effect the amount of jitter reaching the converter.  Thus we finally have a practical use for exotic cables as DAC testers.  If the use of an exotic cable makes a DAC sound better, then the DAC is not performing adequately and should be repaired or redesigned.  If the goal is actually to achieve high quality, rather than just claim it, then this is one of the fundamental tests a designer should use."  And we would add, "Whoever heard of a DAC operating without jitter induced sidebands over 1000' feet of garden variety data cable?  Now that's a properly engineered device!"

Click on the images below for a larger view.

DAC1 Interface Jitter Tolerance - Distortion Vs. Jitter on Digital Input Signal

This following graph is a look at the Eye pattern for 1000' of Belden MediaTwist® Cat 5e (11872A) - Green) and 1000' of General Cable Co. Cat 5e (Cat # 2133458H) - Yellow, along with the minimum signal eye pattern of the DAC1 - Blue.  Also included in this graph is the normal AES/EBU four volt output level found in normal professional digital audio equipment - Cyan.  The red "box" is the minimum tracking recommendation for a digital audio receiver as specified by the Audio Engineering Society.  As can be seen the DAC1 easily operates with total freedom from jitter at the end of a 1000' length of CAT5e data cable DAC1 Eye Pattern - Cable Eye Patterns from: Normal AES (Cyan), end of 1000' of Belden MediaTwist® (Green), 1000' of Home Depot Cat 5e Cable (Yellow) and Minimum DAC1 Input Requirements (Blue)

The following graph shows the output of the DAC1 having been fed 12.75 unit intervals of jitter.  Since jitter creates double sideband modulation products from the "carrier", in this case a 10 kHz audio tone, and the jitter frequency is 5-kHz, jitter induced sidebands of 5 and 15-kHz should be seen if jitter makes it to the DAC decoder chip.  The complete absence of these 5-kHz sidebands shows the power of UltraLock™ in providing total freedom from jitter induced audio products within the DAC1.   DAC1 16K B-H FFT Analysis - Total Freedom from Jitter Induced Sidebands (12.75 Unit Intervals of 5-kHz Jitter on the Audio Data)

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