LA4 - Bench Test - John Atkinson, Stereophile
LA4 - Bench Test
"Benchmark's LA4 is the widest-bandwidth, widest-dynamic-range, lowest-noise, lowest-distortion preamplifier I have encountered."
- John Atkinson
"I measured the Benchmark LA4's performance with my Audio Precision SYS2722 system (see the January 2008 "As We See It")."
Frequency Response
"The preamplifier's frequency response in both balanced and unbalanced modes was flat from 10Hz to 200kHz both into the high 100k ohm load and into 600 ohms was taken with the LA4's volume control at its maximum setting; both the response and the superb channel matching were identical at lower settings of the control."
Gain Accuracy
"The gain for the balanced inputs to the balanced output with the volume control set to "+15" was exactly 15dB, and reducing the control to "0.0" resulted in a gain of 0dB—ie, the output voltage was the same as the input voltage."
Input and Output Impedance
"The LA4's balanced input impedance was both usefully high and higher than the specified >50k ohms, measuring 80k ohms (40k ohms per phase) at 20Hz and 1kHz and still 75k ohms at 20kHz."
"The balanced output impedance was a low 61.5 ohms, the unbalanced impedance 201 ohms, both values consistent across the audio band."
Channel Separation
"Channel separation was simply superb, at >140dB, R–L, and >132dB, R–L, below 2kHz, respectively decreasing to 130dB and 112dB at 20kHz."
"The superb separation measurement is a testament to excellent circuit-board layout, something I have commented on before with Benchmark D/A processors."
Noise
"From balanced inputs to balanced output, the Benchmark preamp offered extremely low noise, with virtually no power-supply–related spuriae in its output."
Headroom
"The LA4's balanced output doesn't clip (ie, when the THD+N reaches 1%) until a very high 24V."
THD
"I looked at the spectrum of the distortion at a similarly high output level; while the second and third harmonics can be seen, these are still at astonishingly low levels: each harmonic is at or below –120dB (0.0001%) and is close to the residual level of these harmonics in my Audio Precision SYS2722's signal generator."
IMD
"Tested for intermodulation distortion in balanced mode with an equal mix of 19 and 20kHz tones at peak level of 5V, the second-order difference product at 1kHz was effectively absent, and the higher-order products all lay at or below –114dB."
Conclusion
"Benchmark's LA4 is the widest-bandwidth, widest-dynamic-range, lowest-noise, lowest-distortion preamplifier I have encountered."
- John Atkinson, Stereophile Magazine
The above is just a brief summary of John Atkinson's independent lab tests. Please follow the link below to read his entire test report which includes 9 high-resolution test plots (including the two shown above).
Also in Reviews
Benchmark Converters at Abbey Road - Geoff Pesche
"What are the Latest Advancements in Mastering?"
"Geoff Pesche weighs in on how the mastering team at Abbey Road Studios achieve first-class results." - Mix with the Masters
"The biggest sonic improvement in mastering in the last 5 or 6 years is D/A and A/D converters and that's very very important - what you have at the front and the back of the chain."
"We use fairly new Benchmark converters front and back."
"Abbey Road like a uniformity between the rooms so all of the rooms have the same A/D and D/A conversion."
- Geoff Pesche, Mastering Engineer, Abbey Road Studios
DAC3 Review - Alan Sircom, hi-fi+
"A Damn Good, No-Frills Digital Converter"
"Benchmark Media Systems’ no-nonsense approach to all things audio is rare today."
"Uniformly Good"
"This is a DAC that’s uniformly good at everything. It resolves well, has good imaging properties."
"It makes a balanced, honest sound that allows you to sit and listen to music for hours. That is what makes Benchmark’s products consistently popular with audio engineers. You don’t want ‘bright’ if you sit at a mixing desk 10 hours a day. "
"Leave No Trace"
"It also has the latest version of Benchmark’s jitter attenuation system (UltraLock3) and doubles down on the digital demon with its multi-mode asynchronous USB system."
"Benchmark also uses the distortion compensation facilities built into the ESS chip to reduce second and third order distortion."
"The net result is a DAC that delivers lower distortion, lower noise, less passband ripple, faster signal switching and locking onto signals and a more linear frequency response."
"The Benchmark Media Systems DAC3 B is very much in the ‘leave no trace’ school of good audio."
- Alan Sircom, hi-fi+
DAC3 - Award Nominee - Best Digital Audiophile Product of 2024 (Cost No Object)
2024 Nominees
- Benchmark Media DAC3 B DAC, $1895
- Bricasti M3 DAC, $6000
- Bricasti M19 CD-SACD Player, $10,000
- T+A DAC 200, $7620
- Weiss Engineering Helios DAC, $21,995
"There was some debate about whether anybody can hear the differences above a good Chi-Fi DAC like the Topping D90. Unless you are missing most of your high-frequency hearing, you can hear where a high-end DAC makes a difference."
The Bricasti M3 is a great example of that performance in a $6,000 DAC."
"The Benchmark DAC3 B is an audiophile DAC, with pro audio roots, that punches way above its weight."
