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It's time to hear what Doug Schroeder has to say about

the $975, 2-Channel 24-bit 192kHz

Benchmark Media DAC1

 

June, 2007

 

 
 

Specifications:

(Warning! Extensive specifications are listed below. These have been attached to this review as a service to the audiophile community in contributing to information overload. Do not allow this to deter you from reading the article! We will not be offended if you merely scroll down to the article and largely ignore this critical but arcane information.)

 
 
 

Digital Inputs

Number of Digital Inputs (switch selected)

3 (XLR, Coaxial, TOSLINK)

Number of Audio Channels

2

Input Sample Frequency Range

28 to 195 kHz

Maximum Input Word Length

24 bits

Digital Input Impedance on XLR input

110 Ω

Digital Input Impedance on Coaxial input (Jumper Selected)

75 Ω or Hi-Z (Bridging)

Transformer Coupled Digital Inputs

Yes

DC Blocking Capacitors on Digital Inputs

Yes

Transient and Over-Voltage Protection on Digital Inputs

Yes

Minimum Digital Input Level

300 mVpp on XLR, 150 mVpp on Coaxial

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

Jitter Attenuation Method

Benchmark UltraLock.

Balanced Analog Outputs

Number of Balanced Analog Outputs

2

Output Connector

Gold-Pin Neutrik™ male XLR

Output Impedance

60 Ω

Output Level Calibration Controls

10-turn trimmers (1 per output)

Calibration Adjustability

2 dB / turn

Output Level Range (at 0 dBFS) In Calibrated Mode

+9 dBu to +29 dBu (Attenuator off)
-1 dBu to +19 dBu (Attenuator = 10 dB)
-11 dBu to +9 dBu (Attenuator = 20 dB)
-21 dBu to -1 dBu (Attenuator = 30 dB)

Output Level Range (at 0 dBFS) In Variable Mode

Off to +29 dBu (Attenuator off)
Off to +19 dBu (Attenuator = 10 dB)
Off to +9 dBu (Attenuator = 20 dB)
Off to -1 dBu (Attenuator = 30 dB)

Output Level Variation with Sample Rate (44.1 kHz vs. 96 kHz)

< +/- 0.006 dB

Unbalanced Analog Outputs

Number of Balanced Analog Outputs

2

Output Connector

RCA

Output Impedance

30 Ω

Output Level Calibration Controls

Shared with Balanced Outputs

Output Level Range (at 0 dBFS) In Calibrated Mode

-6 dBu to +13.5 dBu

Output Level Range (at 0 dBFS) In Variable Mode

Off to +11 dBu

Calibration Adjustability

2 dB / turn

Output Level Variation with Sample Rate (44.1 kHz vs. 96 kHz)

< +/- 0.006 dB

Factory Preset 2vRMS (8.2 dBu)

 

HPA-2™ Headphone Outputs

Number of Headphone Outputs

2

Output Connector

¼" TRS

Output Impedance

0 Ω

Output Level Control

Stereo Control on Front Panel

Output Level Range (at 0 dBFS) into 60 Ω Load

Off to +21 dBu

Audio Performance

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

Interchannel Differential Phase (Between DAC1 Units)

+/- 0.5 degrees at 20 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

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
1.45 ms at 108 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

Input Operating Voltage Range — VAC RMS

110 V setting — 90 V min, 140 V max
220 V setting — 175 V min, 285 V max

Frequency

50-60 Hz

Power

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

Dimensions

½ Rack Wide, 1 RU High

 

Depth behind front panel

8.5" (216 mm)

Overall depth including connectors
but without power cord or BNC-to-RCA adapter.

9.33" (237 mm)

Width

9.5" (249 mm)

Height

1.725" (44.5 mm)

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.

 
 

Manufacturer:

Benchmark Media Systems, Inc.

5925 Court Street Road

Syracuse, NY 13206-1707

Tel. 800-BNCHMRK (800-262-4675)

Or (315) 437-6300

 

URL: http://www.benchmarkmedia.com

Email: sales@benchmarkmedia.com

 
 
 
 
 

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, John 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 affect 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!"

 
 

 

UltraLock™ Performance - Distortion Vs. Jitter on Digital Input Signal

 
 

The 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, available at Home Depot, 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.

 
 

 

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 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.

 
 

 

Total Freedom from Jitter Induced Sidebands
(12.75 Unit Intervals of 5-kHz Jitter on the Audio Data)

 
 
 
 

Benchmark. That’s a loaded name for a component manufacturer. It brings to mind thoughts not only of quality build and performance but, for those philosophically inclined, also epistemological questions pertaining to the nature of high-end audio. A benchmark is a point of reference or standard by which something can be judged. Benchmark Media has chosen a bold name, one that suggests they are the standard by which listeners can judge quality music reproduction.

How do we know that a component made by a company is in fact a benchmark? How do we know it’s worthy of being the touchstone for audio reproduction? Further, how does an individual determine whether they are merely operating from their own point of reference, or from an established common point of reference? Would Benchmark’s DAC1 be a commendable component to establish a personal reference?

Every audiophile ends up selecting a personal sound preference; but there are essentially two ways to go about arriving at that preference. One may defer to authorities and mimic their expertise and recommendations. Alternatively, an individual can evaluate scads of components on their own and find their desirable sound. Even in those instances, I have not encountered any hobbyist who is completely free from the influence of others’ preferences. Often while in the search for a component they select themselves, audiophiles will scour the Earth for opinions of others.  

A short while ago, Dave Magnan, the founder of Magnan Audio Cables, whose products I am currently reviewing, spoke of his and my methods of finding superior components which we have not auditioned. I cull manufacturer’s comments, professional reviews and audiophile impressions of a component while weighting each appropriately. In principle, I do not adhere strictly to one or the other reviewer’s remarks since I feel the variables inherent in reviewing are myriad, making it too difficult to isolate someone who will always hear things my way. Dave, on the other hand, focuses in on one or two reviewers who seem to have their ears tuned similarly to his own – he’s found their impressions of equipment to mirror his own. In both cases, the establishment of the reference is at least partially based in someone else’s head.

I have found that all audiophiles (this may, in fact, be universal) use someone else’s yardstick, someone else’s benchmark, in order to measure their own ability to create “good sound.” They either attend a show, read online and printed magazines, scour posts, visit a dealer, compare impressions or findings with other designers and manufacturers – somehow they connect with someone else to “compare notes.” Just as there is in reality no such thing as a “self-made” man, there is no such thing as a self-made audiophile. We all seem to pick our heroes whose sound we want to emulate in our systems.

Certainly one means of establishing a benchmark is through testing. Speaking of specifications, never have I seen such a cascade of specifications attached to a DAC as with the DAC1. I included the entire listing partially as a joke; it’s not every day that the specifications are as long as the review!  However, Benchmark Media does not consider its specifications a joke – it’s evidence that they don’t fool around when it comes to assessing the performance of their designs. In answer to the epistemological question – how can we know the DAC1 is a good standard? – Benchmark is willing to trot out every iota of information to assuage the objectively minded audiophile. If you need to see numbers to convince you that a product makes good sound, Benchmark wants you to see plenty of numbers! Of course, this doesn’t necessarily mean it will sound good to your ears, but it does reinforce the belief that Benchmark is hitting the mark when they claim by way of their UltraLock technology, they have produced a DAC that is superior in eliminating jitter and revealing more detail than conventional DACs.

The DAC1 was created with three target users in mind: the professional studio, home use by audio professionals, and audiophiles. Indeed, the DAC1 has been well received by studios and has made inroads into the audiophile community.  It is feature-laden and smartly laid out. Earlier versions had mounting hardware incorporated into the front plate, which weren’t the most pleasing for aesthetically picky audiophiles. The newer face plate is more comely with machined aluminum niches containing the name, three LED status display, and input selector toggle along with twin HPA2 headphone jacks. An unlit attenuator knob with a rough finish on its grip, like a weight room curling bar, completes the front. Does this suggest that professional audio engineers attempt to set levels with things like potato chip oil on their hands, hence the need for a better grip?

The back is where the real action is at, chalked full of goodies like detachable IEC, digital, optical and XLR inputs, as well as single-ended and optional calibrated or variable balanced outs. In addition to the calibrated or variable output, the analogue outputs can be muted while keeping the headphone jacks active. The rough satin black finish of the chassis, combined with the thick aluminum face plate, make the DAC1 appear business-like but not purely utilitarian. The smaller, low profile chassis meets the desires of space conscious professional users.

 
 

PAGE 2 - Audition & Conclusion