Our DAC2 D/A converter will provide exactly the same performance at either 96 kHz of 192 kHz. However, in most cases, many A/D converters (used to record the music in the studio) achieve better performance at 96 kHz than they do at 192 kHz. But, these differences will be very small.
Benchmark began in 1983 as the "Benchmark Sound Company", a small operation working out of a garage in Garland, Texas. Allen H. Burdick, Founder Our founder, Allen H. Burdick, began by building very high-performance audio equipment to meet the specialized...
Benchmark has recorded a lab demonstration that shows what happens when a standard two-wire cable is exposed to common sources of magnetic interference.
You will be able to hear the interference, see it on an oscilloscope, and view its spectrum on an FFT. A star-quad cable is exposed to the same sources of magnetic interference and the results are compared. This demonstration shows the dramatic difference between the two cables. The star-quad cable provided a 20 to 50 dB reduction in magnetic interference, keeping the interference below audible levels.
Recording Engineers and Audiophiles often distrust audio measurements and specifications. It is not uncommon to hear claims that a product measures poorly but sounds good. Occasionally we also hear claims that a product measures well but sounds bad.
This whitepaper documents significant differences between three headphone amplifiers that have nearly identical published specifications.
AHB2 - John Siau Explains what's Inside Benchmark's Unique Amplifier
"John is a long-time audiophile. In fact, it was his love of music and audio that originally inspired his interest in electronics and prompted him to pursue a degree in electrical engineering at Syracuse University."
"“It became clear that we would not reach our goals if we designed a conventional power amplifier,” John said. “We realized that we needed to look at some unique solutions. We were very focused on eliminating crossover distortion in the output stage because we felt that this was one of the most important factors in the sonic performance of the amplifier. We began experimenting with ...”"
Rory Rall shows a Storm Trooper the AHB2 power amplifier at the NAMM 2016 Show, and explains the new THX AAA Technology. Rory was heard to say: "These are the amplifiers that you are looking for."
The circuits used to drive headphones are often added to a product without careful consideration of the difficult loads presented by high-quality headphones. The most common circuit is an opamp driver followed by a 30-Ohm series resistor. The series resistor provides short-circuit and overload protection while isolating the opamp from the inductance and capacitance of the headphones. The series resistor protects the opamp while keeping it stable. In contrast, today's state-of-the-art headphone amplifiers eliminate the series resistor, and use a high current driver. This change reduces distortion and flattens the frequency response when a headphone is driven. These new high-end designs are often called "0-Ohm" headphone amplifiers, and are ...
The movement of headphone transducers must be well controlled in order to produce high-quality audio. It is easy to build a headphone amplifier that produces sound. It is an entirely different matter to produce an amplifier that is clear, clean, and enjoyable.
Headphone amplifiers need power and accuracy to achieve control. They also need to be protected from short circuits and overload conditions. The cheap, dirty, and common way to protect the amplifier is to add a series resistor between the amplifier and the headphone jack. This simple solution protects the amplifier from short circuits and overloads. Unfortunately, the resistor isolates the headphones from the amplifier, causing a loss of control. This ...
In case you hadn't seen it, it's worth a quick read for those trying to stay up with some of the bit-rate/sample-rate discussions we've had here: Audio Myth - "24-bit Audio Has More Resolution Than 16-bit Audio" - sdolezalek
It is easy to build a headphone amplifier that produces sound. It is an entirely different matter to produce an amplifier that is clear, clean, and enjoyable.
Headphone amplifiers need to provide enough voltage and current to achieve a suitable listening level. They must also be able to cleanly deliver the required output. Furthermore, they need to be able to control the transducers.
If these goals are not achieved, a good set of headphones can sound bad.
The AHB2 power amplifier is named in honor of Benchmark's founder, Allen H. Burdick. Allen had a life-long passion for audio, and became one of the leading innovators in the pro-audio industry. Allen was a perfectionist and a prolific engineer. Most early Benchmark schematics bear the initials A.H.B.
Allen's DA101 distribution amplifier helped define the performance goals of the AHB2 power amplifier. The result is an amplifier that Allen would have been proud to call a "Benchmark".
In loving memory of Allen H. Burdick (June 29, 1942 - September 27, 2013).
The ADC16 is equipped with Benchmark’s new UltraLockDDS™ clock system. This system utilizes the latest low-jitter clock technology developed for high-frequency RF communications systems.
The master oscillator is a low phase-noise, temperature-compensated, fixed-frequency crystal oscillator with a +/- 2 PPM frequency accuracy. This oscillator drives a 500 MHz Direct Digital Synthesis (DDS) system.
Jitter attenuation is achieved with digital filters in a custom FPGA that controls the DDS system. All jitter-induced distortion artifacts are well below audibility under all operating conditions.
DAC1 - "A clean, lean digitizing machine"
"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."
"It’s more than a DAC, it’s a pretty doggone good preamp too!"
"It presents hyper-nuanced, super clean sound."
"The Benchmark is a clean, lean digitizing machine. It does set the standard at its price point for pure, unadulterated digital signals coming to your nearest amp(s)."
"If you’re after the most measurably perfect CD sound and endless detail, put it on your own test bench – your audio rack."
- Doug Schroeder, dagogo
The AHB2 and SMS1 will be demonstrated at the Rocky Mountain Audio Fest October 10-12, 2014. Come experience this stunning combination in person. Meet Sales Manager Rory Rall and Speaker Designer Dave MacPherson. Enter to win a Benchmark DAC (1 winner per show). We will be accepting orders for the AHB2 at the show.
The AHB2 and SMS1 will be on display at the AES Convention in LA October 9-12, 2014. Stop by booth 1421 to meet John Siau and other members of the engineering team. Enter to win a Benchmark DAC (1 winner per show). We will be accepting orders for the AHB2 at the show.
Since 1983, Benchmark products have been designed, assembled, and tested in the USA. Our products are now shipped to every continent, but we are firmly committed to keeping our manufacturing in the USA.
Watch us transform a solid bar of aluminum into a finished Benchmark faceplate. Learn how sheets of metal are formed into finished enclosures. Watch as hundreds of tiny electronic components are accurately placed on circuit boards. See the chassis and electronic components converge at final assembly where each product is hand assembled. Watch our techniciansrun a comprehensivesequence of performance and safety tests.
Bennett visited our booth and dropped his card in our fishbowl, never expecting to win. Yesterday was his lucky day!
Rory emailed Bennett to let him know that he had won. Here was his response:
"Hey Rory, I checked my email... holy ...! Well, that's about as exciting as email gets. I didn't forget I dropped my business card into the fish bowl, but I had no hope. Hope leads to the dark side, or something."
It's on your iPhone, your Android and your computer. It's even on those CDs you put on a shelf somewhere. Audio that goes to 11. If 10 is the clip point of digital audio, you actually have digital recordings that go to 11. Nigel Tufnel of Spinal Tap was on to something in 1984 when he explained that his Marshal amps "go to 11".
But, it's not just Spinal Tap recordings that go to 11, every recording you own may also go to 11! How is this possible? If 10 is the clip point of digital audio, how can there possibly be an 11? And, if we use Nigel's logic; if 10 is good, why isn't 11 better?
Most people have seen the CE mark on electronic equipment, but few have had the opportunity to witness the tests that are required to conform to the CE specifications. This post takes the reader on a behind-the-scenes photo-tour of the CE tests of Benchmark's new AHB2 power amplifier.
In my last post, "Audio that Goes to 11", I made the bold assertion that most of our audio recordings contain peaks that exceed the limits of our digital hardware. In this post I will show how this happens, and explain why this is a problem in PCM audio systems.
Do we throw out PCM and move to DSD?
Visit Benchmark Media Systems in room 322 & the lobby-level Lakeshore Ballroom B at AXPONA, North America's Premier Event for Audiophiles and Music Lovers, April 24 - 26, 2015. We can't wait to see you there!
The Lakeshore B Ballroom will feature a very special multi-vendor high-resolution surround-sound demonstration featuring Benchmark conversion and amplification.
Room 322 is an all-Benchmark room featuring the DAC2 HGC preamplifier, the AHB2 power amplifier, and SMS1 speakers. Visitors to room 322 are eligible to win a Benchmark DAC1 HDR.
DAC3 HGC - "Benchmark has taken an already remarkable product and moved it to the next level"
"Benchmark Media Systems, Inc.’s DAC series of high-performance digital-to-analog converters (DACs) have earned the respect of audio enthusiasts and professional users alike for their state-of-the-art performance, including exceptional audio transparency and vanishingly-low levels of noise and distortion. Now Benchmark has made its DAC3 even better with the upgrade to ESS Technology’s new ES9028PRO DAC chip."
"Benchmark considers the THD compensation to be the most significant improvement."
What’s the value of HD video without accompanying high-resolution sound?
Home theater screens continue to get bigger and the pixels multiply; it was only yesterday that 1080p was the standard and now 4K is gaining prominence. However, home audio sound technology hasn’t kept pace.
There is a raging debate over the definition of "High-Resolution Audio". The focus of this debate has been misdirected by a lot of marketing hype. High-Resolution Audio will only truly arrive when the sum total of all defects in the audio chain become inaudible. We are not there yet, but we are getting close. The final chapter will not be higher sample rates and more bits. The final chapter will be achieving the necessary improvements to critical components in the signal chain.
If your playback system can't resolve anything better than CD quality, then "High-Resolution Audio" will remain an illusion.
High-Resolution Audio systems offer the promise of an extended high-frequency range. High-Resolution digital systems now operate at 2 to 4 times the sample rate of the standard CD. This means that these systems have the capability of extending the playback frequency range well above the 22 kHz limit of the standard CD. Does this added high-frequency range improve our listening experience? How high is high enough? Do we really need anything over 20 kHz?
DAC2 DX - "Sonic performance in an entirely new league"
"The sonic performance of the DAC2 DX is in an entirely new league when compared to the DAC1 (I still have a DAC1 USB available for comparison). First, the tonal balance is extremely neutral, without any of the DAC1’s brightness. The DAC2 DX also has a harmonic richness which, by comparison, I find somewhat lacking in the DAC1."
"Since I reviewed the OPPO BDP-105 in audioXpress, I’ve been searching for a reasonably-priced D/A converter that will actually improve the OPPO’s performance as a stand-alone player."
"The Benchmark DAC2 DX is a hands-down improvement over the OPPO as a stand-alone player, especially in the areas of inner detail, soundstaging, high-frequency airiness, and bass. The extreme low end is both deeper and better controlled than the OPPO. Dynamics, across the spectrum, are excellent."
"Benchmark’s goal in all of its products is ultimate precision and accuracy, and the DAC2 DX tells the truth about every source it’s fed, while being free of unmusical artifacts sometimes associated with digital audio."
- Gary Galo, audioxpress
DAC2 HGC - "Sonically as neutral a DAC as I have ever heard"
"The Benchmark DAC2 HGC is sonically as neutral a DAC as I have ever heard. It borders on a somewhat light sonic texture with absolutely no digital hardness or extreme brightness. The sound is quite detailed and well defined with no warmth or added richness. One attribute of the DAC2 HGC I enjoyed was its very well defined and articulated bass."
"What I enjoyed most about the Benchmark DAC2 HGC was the way it handled native DSD files. DSD playback added richness to the sound with additional midrange weight that added realism to the reproduced music."
"The DAC2 HGC was a pleasure to listen to with PCM and especially with native DSD files. Its acoustic honesty and functional precision was easily observed and appreciated."
- Steven Plaskin, Audio Stream
About 33 years ago, Benchmark's founder, Allen H. Burdick, began building analog audio distribution amplifiers for television networks. This application demanded an audio amplifier with a very wide frequency response, very low noise, and very low distortion. The Benchmark DA101 distribution amplifier had a 160 kHz bandwidth, THD+N of 0.00044%, and a SNR of 130 dB, but the power output was only about 40 watts in bridged mono.
For many years, we used our distribution amplifiers to drive the speakers in our listening room. We couldn't buy an amplifier that came close to the performance of our distribution amplifiers, and Allen had often talked about building a bigger amplifier that could match the performance of the DA101.
In 2011 we began to talk about making Allen's dream for a power amp a reality. The goal was to meet or exceed the performance of Allen's DA101, while scaling up the power by a factor of 10.
Benchmark ... The Measure of Excellence® As our name implies, we are committed to excellence. Benchmark products are designed and built by audio enthusiasts. We are musicians, audiophiles and audio professionals who are passionate about audio quality. We also are passionate about the...
Benchmark DAC1 and DAC2 converters are equipped with Benchmark’s HPA2™ headphone power amplifier. This is a high-current design with very low output impedance (less than 0.1 Ohms). It is capable of driving a wide variety of headphones while achieving extraordinarily low distortion. The full rated performance of the DAC is achieved at the headphone jack while driving two sets of headphones. THD+N is less than 0.0003% under full load. The HPA2™ may be the quietest and cleanest headphone amplifier available.
The HPA2™ has jumpers that allow it to be matched to the sensitivity of your headphones. These jumpers can be used to optimize the system performance.
"Analog audio has infinite amplitude resolution."
"Digital audio is limited to a finite number of steps."
"24-bit audio has more resolution than 16-bit audio."
While it is true that digital systems quantize the amplitude of the audio signal to the nearest step in the digital encoding system, this does not necessarily mean that digital systems cannot have infinite resolution. Contrary to popular belief, digital systems can provide infinite amplitude resolution if they are properly dithered.
Many Benchmark products include our HPA2™ headphone power amplifier. Unlike most headphone amplifiers, the HPA2™ is designed to behave like a small but very clean power amplifier. What makes the HPA2™ different, and what do we mean when we say that the HPA2™ is a "power amplifier"?
The music industry is struggling to define High-Resolution Audio or "HRA". In doing so, most have focused on the delivery formats - analog vs. digital, 24-bits vs. 16-bits, 1X vs. 2X and 4X sample rates, PCM vs. DSD, uncompressed vs. compressed.
But, High-Resolution Audio is much more than the delivery format ...
"High-Resolution Audio Requires High-Resolution Performance at all Stages of the Recording and Playback Chain"
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.
This paper is a short summary of the decisions that led to our choice of the 110 kHz sampling rate.
SEAS, a well-known manufacturer of high-quality loudspeakers, selected the Benchmark AHB2 as a key component for use in testing loudspeakers. They created an innovative test system that measures loudspeaker motor strength and moving mass with higher accuracy than previous methods. This new measurement system was documented in the December 2017 Journal of the Audio Engineering Society.
According to the AES paper, the SEAS team selected the Benchmark AHB2 for the following reasons:
"A Benchmark AHB2 amplifier is used, which has excellent signal-to-noise ratio and bandwidth, low output impedance, and is suitable for laboratory use (with advanced overload protection)."
The AHB2 was designed to outperform all competing power amplifiers in terms of noise and distortion. The result is an amplifier with unrivaled transparency.
Our goal was to create the ultimate amplifier for the enjoyment of music. It is nice to know that the AHB2 is also being used to test new and improved loudspeakers!
By John Siau and Allen H. Burdick
This paper addresses these questions:
Monty Montgomery takes us into the lab and uses a series of simple demonstrations to bust some very common myths about digital audio. Test your knowledge of digital audio. This video is fun to watch and easy to understand! Monty takes some difficult concepts and demonstrates them in a clear and simple manner.
Have doubts about Nyquist? Have a fear of stairsteps? Are you worried about ringing? Ever wonder what digital audio does to the timing of transients? This video is for you!
Myth- "Digital audio has stairsteps."
Myth- "Increased bit depths reduce the stairsteps."
Myth- "Analog tape has more resolution than digital audio."
Myth- "Dither masks quantization noise."
Myth- "Signals lower than one LSB cannot be reproduced."
Myth- "Digital filters make square waves and impulses ring."
Myth- "Digital systems cannot resolve timing between samples."
The Sennheiser HD 650 is a reference-quality, open, over-the-ear, dynamic headphone with extremely natural sound, image, and fidelity. You don’t just hear the music – you are immersed in it. Experience the legendary Sennheiser HD 650. Recommended by Benchmark "The Sennheiser HD 650 is...
Variable-pitch features add versatility to CD players. Unfortunately, these features usually create jitter problems. Benchmark’s UltraLock™ jitter-attenuation system provides a unique solution that is fully compatible with variable-pitch transports.
This application note addresses these common questions and presents some guidelines for selecting headphones with the proper impedance and sensitivity.
The following measurements and scope photos demonstrate the effectiveness of the feedforward system in the AHB2.
From the first Watt to the last Watt, the AHB2 shows no evidence of crossover distortion. In contrast, all conventional class-AB amplifiers have crossover-distortion artifacts.
Dick Olsher once said that "the first Watt is the most important Watt". We agree!
"Balanced headphone amplifiers are better."
"If balanced line-level connections work well, balanced headphone outputs should also work well."
Benchmark does not offer balanced headphone outputs on any of its products. The reason for this is that a voltage-balanced interface serves no useful purpose when driving headphones. The truth is that a conventional single-ended headphone drive is technically superior to a balanced drive. This paper explains why single-ended headphone amplifiers are inherently more transparent than balanced headphone amplifiers.
Two or more Benchmark DAC1 or DAC2 converters can be used together in phase-coherent multichannel audio systems even though their internal clocks are not synchronized. This seems to defy logic, but an examination of the system details reveals why this is possible.
Blu-ray disks often contain high-resolution audio formats. Dolby TrueHD and DTS-HD are two Blu-ray audio encoding formats that support lossless high-resolution audio. These systems support up to 8 channels of 24-bit, 96kHz audio, or up to 6 channels of 24-bit 192 kHz audio.
Blu-ray disks may seem like an ideal solution for the distribution of high-resolution audio, but there are problems. It is not easy to gain access to the high-resolution audio stored on these disks.
Our solution was to set up a PC-based music (and video) server. We used a Blu-ray equipped PC running Windows 7 and the JRiver MediaCenter software.
This application note provides a guide for setting up a music server that can play the lossless high-resolution audio tracks found on DVD and Blu-ray disks.
The performance of the AHB2 would not have been achievable without taking a radical approach to power amplification. In many ways, the AHB2 is a complete 180 degree departure from traditional high-end amplifier designs. There is nothing ordinary about the Benchmark AHB2!
Take a look inside this unique audio power amplifier!