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[#528] Benchmark DAC1 Fans Club 出年會過台灣，諗住帶埋呢部DAC過去，睇MANUAL，睇MANUAL係唔係可換過FUSE就得？ FUSE有分220V同110V？ Fuse Holder The fuse holder is built into a drawer next to the IEC power connector. The drawer requires two 5 x 20 mm 250 V Slo-Blo® Type fuses. The drawer includes a voltage selection switch with two settings: 110 and 220. The fuse rating for all voltage settings is 0.50 Amps. The AC input has a very wide input voltage range and can operate over a frequency range of 50 to 60 Hz. At 110, the DAC1 PRE will operate normally over a range of 90 to 140 VAC. At 220, the DAC1 PRE will operate normally over a range of 175 to 285 VAC. Caution: Always install the correct fuses. Always insure that the voltage setting is correct for your locality.		YuChai 正式會員 223.xxx.xxx.10	2020-12-13 16:38

[#527] Benchmark DAC1 Fans Club
Benchmark DAC2 VS Benchmark DAC1 HDR
http://theaudiocritic.com/plog/
"Benchmark DAC2 HGC

peteraczel | 20 August, 2013 15:49

PCM and DSD D/A Converter with Line-Level Preamp and More
Benchmark DAC2 HGC

Benchmark Media Systems, Inc., 203 East Hampton Place, Suite 2, Syracuse, NY 13206-1633. Voice: (800) 262-4675 and (315) 437-6300. Fax: (315) 437-8119. E-mail: sales@benchmarkmedia.com. Web: www.benchmarkmedia.com. DAC2 HGC stereo preamplifier with PCM and DSD D/A converter, headphone amp, and asynchronous USB, $1995.00. Tested sample on loan from manufacturer.

[For better pictures than I can reproduce here, please go to the website indicated above.]

The super D-to-A converter with line-level preamp capabilities is a relatively recent format, although scattered examples of it have been around for a number of years, such as the Benchmark DAC1 HDR (reviewed here in July 2009). Lately a number of high-end boutique companies have seen an opening and announced some insanely overdesigned models at astronomical prices. I haven’t had my hands on any of these (and never will), but it baffles me what they can do that the new Benchmark DAC2 HGC, at a fraction of their price, can’t. The latter has such a complete set of features and capabilities, and such amazing specifications, that I can’t see how any outrageously costly unit could trump it.

The Design

What is required to design a super DAC/preamp in the second decade of the 21st century is no mystery. You start with the best DAC chip that money can buy, the world champion ESS Sabre³² Reference 32-bit 8-channel audio DAC, and use all 8 channels for stereo, 4 per side. In that deployment, the digital noise reduction spec is 133 dB and the total harmonic distortion (THD) is –120 dB (0.0001%). You can’t do any better; that’s what Benchmark has in the DAC2 HGC, and that’s what the megabuck high-enders have in their models, also. As for the analog section, you go with the Texas Instruments (formerly National Semiconductors) LME49860 operational amplifier, which has a specified voltage noise density of 2.7nV/√Hz and a THD of 0.00003% (–130.5 dB). Low enough for you?

Once you build your device around electronic components with numbers like that and keep the construction quality high, as Benchmark does, there isn’t much headroom for improvement, nor much reason for a higher price than $1,995.00. And that’s just for starters; the DAC2 HGC goes well beyond the DAC1 HDR (which is still an “A-team” contender) with a large number of new features, such as native DSD conversion and a hybrid gain control (HGC). The latter is capable of active analog, 32-bit digital, and passive analog attenuation, thus ending all debates about tradeoffs. I am not willing to list and explain all these new technicalities because you can go to http://www.benchmarkmedia.com/dac/dac2-hgc and read all about them in full detail. (Have you noticed that about 50% of the usual equipment review consists of a restatement of the manufacturer’s information? In the age of the Web?) You can even download the 68-page instruction manual from http://www.benchmarkmedia.com/sites/default/files/documents/DAC2%20HGC%20Manual%20-%20REV%20D.pdf and pretend you already own the DAC2 HGC. Since I have no doubt about the state-of-the-art status of the unit’s electronic signal paths, I’ll only discuss matters that Benchmark does not.

For example: Despite 16 LED status indicators on the unit’s front panel, you can’t tell whether the DAC2 HGC is in standby mode or totally shut off. Yes, when you first put it in standby mode, the red Dim/Mute LED keeps flashing for a while, as does the blue LED of the muted input, but they stop after a short while, and the panel then looks the same as in power-off mode—no lights at all. This is a bit annoying when you want to listen to something and don’t remember whether the unit should be unmuted or powered up. It’s best to leave it in standby mode at all times when not in use, especially since powering it off sends a 0.15-volt dc pulse through the audio chain, which can result in a serious pop from the loudspeakers if the power amplifier is still on.

These minor annoyances don’t in any way constitute a deal breaker for the prospective purchaser but merely illustrate the learning curve necessitated by the unit’s control functions. The latter are not intuitive; the remote control’s buttons are not quite the same as those on the front panel, and there are quite a few press-twice and press-two-together protocols to activate certain functions. I am sure there are geeks who will relish these secret handshakes, but I would have preferred a brilliantly engineered state-of-the-art device to have

batmanamesIA

正式會員
64.xxx.xxx.165

2013-12-08 11:23

[#526] Benchmark DAC1 Fans Club
Yes, sound siginificant different with xlr to rca converter (remember set it to 0dB, not -10dB

batmanamesIA

正式會員
61.xxx.xxx.111

2012-10-16 21:29

[#525] Benchmark DAC1 Fans Club
thx!!!!!use xlr to rca ,any big difference?? cd player/tuner to dac1,dac1 to amp,all add xlr to rca converter?

最後修改時間: 2012-10-16 20:16:55

krell250

正式會員
218.xxx.xxx.151

2012-10-16 20:08

[#524] Benchmark DAC1 Fans Club
please use xlr to rca converter as your rca source

batmanamesIA

正式會員
61.xxx.xxx.111

2012-10-16 17:40

[#523] Benchmark DAC1 Fans Club
Thats normal, dont remove the cover, The case are used as heatsink (all the regultors like 7805 attached with the cover

batmanamesIA

正式會員
61.xxx.xxx.111

2012-10-16 17:39

[#522] Benchmark DAC1 Fans Club
my Benchmark dac1 is very hot like tube amp,should I remove the cover long time ? Thx!

krell250

正式會員
219.xxx.xxx.65

2012-10-16 17:26

[#521] Benchmark DAC1 Fans Club
1平衡轉RCA頭

2 set the jummper according to the photos

batmanamesIA

正式會員
61.xxx.xxx.111

2012-10-16 15:42

[#520] Benchmark DAC1 Fans Club
thx!!!

krell250

正式會員
218.xxx.xxx.200

2012-10-16 15:29

[#519] Benchmark DAC1 Fans Club
好聲XLR調教-10db,0dB

not rca

batmanamesIA

正式會員
61.xxx.xxx.111

2012-10-16 13:42

[#518] Benchmark DAC1 Fans Club
rca 不能調教-10db??

krell250

正式會員
218.xxx.xxx.200

2012-10-16 13:04

[#517] Benchmark DAC1 Fans Club
用rca

no need la

batmanamesIA

正式會員
61.xxx.xxx.111

2012-10-16 05:24

[#516] Benchmark DAC1 Fans Club
買左Benchmark dac1(最舊版), 知悉調教-10db最好聲,不過要拆開外殼才可調教(廠方有指示),請問有冇c hing調教過??如何set去-10db,是用rca非xlr,因為冇說明書不識,謝!!!!!

krell250

正式會員
218.xxx.xxx.121

2012-10-15 23:34

[#515] Benchmark DAC1 Fans Club

Benchmark DAC2 HGC
A New Reference
Benchmark's DAC1 family of D/A converters have been the reference to which other converters have been compared. It is rare to find a converter review that does not draw comparisons to the DAC1. The DAC1 has been the best-selling 2-channel reference-quality converter and is in daily use at many of the finest recording studios and mastering rooms. DAC1 converters are also enjoyed by thousands of audiophiles.
But, Benchmark has just raised the bar ... the DAC2 HGC now defines a new reference.
Performance
The DAC2 HGC outperforms the DAC1 in every respect. It has lower noise, lower distortion, improved accuracy, outstanding musical detail, precise stereo imaging, an advanced digital filter design, and a new high-sample-rate Asynchronous USB Audio interface. All inputs are fully isolated from interface jitter by Benchmark's new UltraLock2™ jitter attenuation system. Internal digital processing and conversion is 32-bits, and includes 3.5 dB of headroom above 0 dBFS. Four balanced 32-bit D/A converter are summed together for each balanced output. The performance of the DAC2 HGC exceeds the measurement limits of today's state-of-the art test equipment. Discover the analog sound of the DAC2 HGC.
New Features
DAC1 customers requested many new features which have been integrated into the new DAC2 HGC:
Sample Rate Display
Word Length Display
More Digital Inputs (5 total)
More Analog Inputs (2 total)
More Analog Outputs (3 total)
Digital Pass Through
Native DSD Conversion
Polarity Switch
Asynchronous USB 2.0
Driverless Asynchronous USB 1.1
Home Theater Bypass
Bi-Directional 12 Volt Trigger
Power Switch
Low Power Consumption
New Benchmark Technologies
Benchmark introduces some exciting new technologies in the DAC2 HGC:
Hybrid Gain Control
High-Headroom DSP
UltraLock2™ Jitter Attenuation System
Quad 32-bit balanced D/A Conversion System
Multi-Mode Asynchronous USB Audio System
Distributed Power Regulation
Hybrid Gain Control
"HGC" is Benchmark's unique Hybrid Gain Control system. The DAC2 HGC combines active analog gain control, passive low-impedance attenuators, a 32-bit digital gain control, and a servo-driven volume control. All inputs are controlled by the rotary volume control. This volume control moves in response to commands from the remote control. Analog inputs are never converted to digital, and digital inputs never pass through an analog potentiometer. Digital inputs are precisely controlled in the 32-bit DSP system. The DSP system preserves precise L/R balance, and precise stereo imaging, while avoiding any source of noise and distortion. Benchmark's unique passive output attenuators provide distortion-free gain reduction without reducing the dynamic range of the converter. The attenuators optimize the gain staging between the DAC2 HGC and the power amplifier. This optimization is absolutely essential for maximizing the dynamic range of the entire playback system. Much of the success of the DAC1 converters can be attributed to the passive output attenuators. Musical details can be obscured by system noise whenever a preamplifier and power amplifier are improperly matched. The" HGC " system will make full use of your power amplifier's dynamic range. Experience new details in your favorite recordings.
Native DSD Conversion
All digital inputs on the DAC2 HGC support native DSD conversion. DoP 1.0 is automatically detected on all digital inputs, and the system seamlessly switches to native DSD conversion. DoP 1.0 is supported by many media players, and DSD downloads are now available from several sources.
UltraLock2™ Jitter Attenuation System
UltraLock2™ is an improved version of the UltraLock™ system used in the DAC1 and ADC1 product families. DSP processing is 32-bits, DSP headroom is 3.5 dB, sample rate is 211 kHz, and jitter-induced distortion and noise is at least 140 dB below the level of the music - well below the threshold of hearing. Benchmark's UltraLock2™ system eliminates all audible jitter artifacts.
High Headroom DSP - with 3.5 dB "Excess" Digital Headroom
All of the digital processing in the DAC2 HGC is designed to handle signals as high as +3.5 dBFS. Most digital systems clip signals that exceed 0 dBFS. The 0 dBFS limitation seems reasonable, as 0 dBFS is the highest sinusoidal signal level that can be represented in a digital system. However, a detailed investigation of the mathematics of PCM digital systems will reveal that inter-sample peaks may reach levels slightly higher than +3 dBFS while individual samples never exceed 0 dBFS. These inter-sample overs are common in commercial releases, and are of no consequence in a PCM system until they reach an interpolation process. But, for a variety of reasons, virtually all audio D/A converters use an interpolation process. The interpolation process is absolutely necessary to achieve 24-bit state-of-the art conversion performance. Unfortunately, inter-sample overs cause clipping in most interpolators. This clipping produces distortion products that are non-harmonic and non-musical . We believe these broadband distortion products often add a harshness or false high-frequency sparkle to digital reproduction. The DAC2 HGC avoids these problems by maintaining at least 3.5 dB of headroom in the entire conversion system. We believe this added headroom is a groundbreaking improvement.
Multi-Mode Asynchronous USB System
Benchmark's USB system supports USB Audio 2.0, DSD, and USB Audio 1.1. It is frequency agile, and will follow sample rate changes initiated by the computer and/or the media playback software. In all modes the USB communications are asynchronous in order to eliminate unnecessary sources of jitter.
The DAC2 HGC has a low-jitter master clock which controls the transfer of audio data from the computer to the USB sub-system. The computer asynchronously transfers audio data to a buffer in the DAC2 HGC. The contents of the buffer are then asynchronously transferred to the D/A conversion sub-system. This second asynchronous transfer eliminates any traces of jitter that accumulate as the data is transferred between the USB and conversion subsystems. No traces of jitter-induced distortion are measurable to our measurement limits (better than -150 dBFS). This truly represents the state-of-the art. Enjoy the convenience of computer playback without compromise. The Asynchronous USB system supports USB Audio 2.0 for high-resolution 192kHz, and DSD playback. No drivers are required for MAC operating systems. An easy-to-install driver adds 192 kHz and DSD capabilities to Windows operating systems.
An asynchronous, driverless USB Audio 1.1 mode supports sample rates up to 96 kHz. This USB mode can be selected from the front panel or from the remote control. The driverless USB Audio 1.1 mode allows quick plug-and-play connections to Windows, MAC, iOS, and Linux operating systems without installing drivers. Just plug in the USB, and the DAC2 HGC becomes an available audio device.
The USB subsystem remains active when the DAC2 HGC is powered down. This prevents interruptions to the computer playback operations and eliminates the need to reconfigure the computer every time the converter is turned on.
Quad 32-bit Balanced Conversion System
Four balanced 32-bit D/A converters deliver audio to Benchmark's low-impedance current to voltage converters. The 4:1 redundancy reduces noise and distortion to levels that set new benchmarks. The conversion system at the core of the DAC2 HGC is as good as it gets. The analog circuits that follow the D/A converter are carefully designed. Benchmark has leveraged its long history of building high-end analog audio equipment, in order to create an outstanding output stage.
Diagnostic Tools - Sample-Rate and Word-Length Indicators
Ever wonder why that 192 kHz 24-bit download on your computer just doesn't sound right? Your media player may be down-sampling to 44.1 kHz and/or truncating to 16-bits. Many media players apply poor-quality sample rate conversion and truncation. Fortunately these problems can be eliminated with the selection a good frequency-agile media player. The sample-rate and word-length displays on the DAC2 HGC confirm the proper operation of your media player.
Polarity Switch
You may encounter recordings with inverted polarity. The DAC2 HGC includes a polarity switch to correct the problem.
Home Theater Bypass
The DAC2 HGC can be integrated into a home theater system. Typically the DAC 2 HGC drives the left and right power amplifiers, and an analog feed from the home theater system is connected to either of the analog inputs on the DAC2 HGC. A programmable Home Theater Bypass function sets the pass-through gain to unity when the surround system is active. The DAC2 HGC includes an indicator light that is illuminated when bypass is active.
Digital Pass Through
The second coaxial input can be reconfigured as a digital output. In output mode, any selected digital input (including USB) will pass through to the coaxial output. The digital pass through is bit-transparent and even supports DSD (DoP 1.0). Dolby digital and DTS formats can be passed through to a surround processor.
Bi-Directional 12 Volt Trigger
Benchmark re-invents the 12 volt trigger. The trigger connection on the DAC2 HGC can be used as an input or output or both, and is compatible with any common 12 volt trigger input or output. The trigger can be used to turn a power amplifier on or off automatically. The DAC2 will also respond to a 12 volt trigger and follow the actions of another audio component.

Power Switch
The power switch can place the DAC2 HGC in standby, or full shut down. In full shut down, the unit will still respond to the trigger input and the IR remote control. Power consumption is less than 0.5 W in full shut down.
Low Power Consumption
The DAC2 uses high-efficiency low noise power supplies and may be operated from any standard international voltage without adjustment. Power consumption is 12 W typical.
Distributed Power Regulation
To achieve the lowest possible noise, the DAC2 HGC uses distributed power supply regulation. Each critical subsystem has at least one dedicated low-noise voltage regulator.
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batmanamesIA

正式會員
61.xxx.xxx.111

2012-10-12 05:30

[#514] Benchmark DAC1 Fans Club
32bit processing, seems ess sabre 9018 products

batmanamesIA

正式會員
61.xxx.xxx.111

2012-10-12 05:21

[#513] Benchmark DAC1 Fans Club
http://www.benchmarkmedia.com/dac/dac2-hgc

mervynlau

正式會員
183.xxx.xxx.89

2012-10-11 22:46

[#512] Benchmark DAC1 Fans Club
DAC2 will be announced on 19 Oct 2012.

mervynlau

正式會員
183.xxx.xxx.89

2012-10-11 10:27

[#511] Benchmark DAC1 Fans Club
Asynchronous Upsampling to 110 kHz
Submitted by michaela on Thu, 2010-07-29 10:12
Author: John Siau
Newsletter Edition: July 2010 Issue
Benchmark DAC1 converters use upsampling techniques to improve the quality of the digital to analog conversion. Benchmark’s choice of 110 kHz is slightly unorthodox. It may seem more logical to upsample by 2X or 4X and convert at standard sample rates such as 88.2 kHz, 96 kHz, 176.4 kHz or even 192 kHz. Intuition may suggest that integer ratios would produce the best results. Intuition may also suggest that higher is better, and therefore 192 kHz would be the “best” choice for an output sample rate. Unfortunately, intuition often leads us down the wrong path if it is not balanced with reason and scientific analysis. Benchmark’s analysis and testing has shown that 110 kHz offers advantages over the choices that seem more reasonable. The following is a short summary of the decisions that led to our choice of the 110 kHz sampling rate:
Asynchronous Upsampling Solved the Jitter Problem
Early in the design process, we identified a distinct performance advantage that could only be achieved using asynchronous upsampling. The digital signals feeding any outboard D/A converter contain too much jitter to directly drive the D/A sampling circuits. However, the conversion clock can be entirely independent from the data transport clock if upsampling is asynchronous. The performance of an upsampling circuit is limited only by the precision of the digital signal processing (DSP) allocated to the process. Our intuition may suggest that synchronous conversion is superior to asynchronous, but this is not the case. Our tests showed that asynchronous upsampling could achieve the same performance as synchronous upsampling, but with the distinct advantage of jitter attenuation. On the basis of jitter attenuation, we chose an asynchronous upsampling process.
The Asynchronous Upsampling Process does not Require Integer Upsampling Ratios
Once we had chosen an asynchronous up-sampling process, we discovered that we were free from the restriction of integer upsampling ratios. Our upsampling algorithm is identical for all up-sampling ratios. In other words, the process required to upsample by 2.29166 is identical to the process required to upsample by a factor of 2. The digital filtering process does not get simpler or better when integer ratios are chosen. Spectrum analysis tests showed that integer and non-integer upsampling ratios produced the same audio quality. This gave us the freedom to explore non-integer upsampling ratios.
Frequency-Shifting Solved Digital Filter Performance Problems
As designers of high-performance converters, we were often frustrated by the fact that we had no control over the digital filters that were built into A/D and D/A conversion chips. With outboard DSP processors it is possible to build digital filters that outperform the filters that are built into even the best conversion chips, but there is usually no means of bypassing the internal filters. We soon discovered that the asynchronous upsampling system gave us a mechanism for frequency shifting the filter that was built into the D/A chip. The near-Nyquist transition band of the filter could be moved above the Nyquist frequency of the incoming audio. This frequency shifting essentially makes this filter invisible to the incoming audio. Given this frequency-shifting tool, we now had the flexibility of replacing the built-in filter with a high-performance external filter. This development was very exciting, and we began to explore the possibilities.
Minimum Upsampling Ratio to Replace Built-in Filters
The filters that are built into D/A conversion ICs can effectively be removed from the signal path by frequency shifting upward by a ratio as small as 1.1 to 1.2. The upsampling ratio must be sufficient to move the transition band of the brick-wall filter to a frequency that is greater than ½ of the input sampling rate. For example, a 44.1 kHz D/A converter usually has a brick-wall filter with a transition band that begins at 20 kHz. An upsampling ratio of 22.05/20= 1.1025 will move this brick-wall filter upward to 22.05 kHz. 44.1 kHz x 1.1025 is 48.51 kHz. In other words 44.1 kHz should be upsampled to at least 48.51 kHz. If an upsampling ratio of 1.1025 is sufficient, 48 kHz should be upsampled to at least 52.8 kHz, and 96 kHz should be upsampled to at least 105.6 kHz. Perhaps Benchmark’s choice of 110 kHz is becoming clearer. But wait, intuition would suggest that 192 kHz should be upsampled to at least 211.2 kHz. Why not upsample everything to 211.2 kHz? Again, intuition alone could have taken us down the wrong path. For the performance reasons explained below, we chose to downsample 186.4 kHz and 192 kHz to 110 kHz.
What Converter Manufacturers Don’t Want You to Know!
An examination of converter IC data sheets will reveal that virtually all audio converter ICs deliver their peak performance near 96 kHz. The 4x (176.4 kHz and 192 kHz) mode delivers poorer performance in many respects. In most cases, noise, distortion, pass-band ripple, stop-band attenuation and other key performance measurements are significantly better in the 2X (88.2 kHz and 96 kHz) mode of operation. Every A/D and D/A conversion IC that we have tested performs better at 96 kHz than at 192 kHz. In most cases THD+N, SNR, passband ripple, and stopband attenuation are all poorer at 192 kHz than at 96 kHz. Based upon these tests, I am not surprised that there is not yet any conclusive evidence that 192 kHz is better than 96 kHz. Given the current state of the art, 192 kHz should sound poorer than 96 kHz. 192 kHz provides additional bandwidth between 48 kHz and 96 kHz but there is no real evidence that this is useful given the limitations of our microphones, speakers, and hearing. 192 kHz adds useless bandwidth while decreasing performance.
If 105 kHz is High Enough, Why Does Benchmark Use 110 kHz?
We chose 110 kHz because this is near the maximum frequency that the AD1853 can reliably operate in the 2x (88.2 kHz and 96 kHz) mode. We measured the performance of the AD1853 vs. sample frequency before choosing 110 kHz. At 110 kHz, the passband of our frequency-shifted AD1853 is 45.8 kHz. When combined with our outboard filters, the DAC1 is almost entirely free of images (alias effects). Given a different converter IC, we could choose a different conversion frequency (our asynchronous upsampling topology allows this flexibility).

batmanamesIA

正式會員
61.xxx.xxx.111

2012-09-15 15:01

[#510] Benchmark DAC1 Fans Club
.http://www.stereomojo.com/Resonessence%20Labs%20Invicta%20DAC%20Review/ResonessenceLabsInvictaDACReview.htm