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Benchmark LA4 Line Amplifier

Name: Benchmark LA4 Line Amplifier
Brand: Benchmark
SKU: 500-17100-101
Rating: 4.7 (20 reviews)

View at Benchmark

Balanced Output

Remote Control

Balance Control

The LA4 line-level preamplifier features the best analog volume control system available at any price.

At each volume setting, relays select pairs of high-precision resistors to attenuate the music to the desired level. This system eliminates the noise, distortion, and L/R balance issues found in more conventional analog volume control systems. Traditional potentiometers and integrated electronic volume controls are the weakest link in most Hi-Fi signal chains. The LA4 removes the weak link while optimizing the system noise performance at each volume setting.

The award-winning LA4 is designed to keep noise and distortion below the 0-dB SPL threshold of hearing at each of the 256 volume control settings. No preamplifier delivers a higher degree of transparency.

The LA4 provides input selection and volume control without adding an "electronic fingerprint" to the music. Discover the difference! Listen to the music, not the electronics.

High-Precision Low-Impedance 256-Step Attenuator
Low-Noise 16-Step Input Gain Stage
Control Range is +15 dB to -127.5 dB in 0.5 dB Steps
High Precision Laser-Trimmed Thin-Film Resistors
12 Relays per Output Channel - 24 Total
Precision Make-Before-Break Timing - Prevents Switching Noise

Ultra Wide 0.1 Hz to 500 kHz Response
Bass is Delivered Without a Phase Shift
Fast, Distortion-Free Transient Response
Linear Phase Response
Accurately Reproduces the Audio Waveshape
Precise Rendering of Stereo Width and Depth
Focused 3-D Stereo Image

2 Pairs of Balanced Line Inputs
Fully-Balanced Differential Input Amplifiers
Fully-Balanced Relay-Controlled Gain Stage
Fully-Balanced Relay-Controlled Attenuation Stage
Fully-Balanced Output Line Drivers
Left, Right and Mono - Balanced Line Outputs
Unbalanced Inputs and Outputs Included

Establishes an Optimal Gain Structure Between the DAC and Power Amplifier
System Noise Performance is Optimized at all Volume Settings
Matches Hi-Fi to Pro Signal Levels
Matches Unbalanced to Balanced Signal Levels
Perfect Match Between a DAC3 and AHB2
Use a Single Remote to Control an All-Benchmark System

Color Touch Screen
Balance Control
-20 dB "Dim" Function
Soft Unmute
Two Bidirectional 12V Trigger Ports
Gain Offset Adjustments for Each Input
Home Theater Bypass Function

Precise, Repeatable Gain Settings Calibrated in dB
Studio +28 dBu Input and Output Capability
Instant A/B Switching Between Sources with Calibrated Input Offsets
Volume Knob uses Long-Life Heavy-Duty Optical Encoder
Long-Life Telcom-Grade Gold-Contact Relays
Rack-Mount Version Available

The Benchmark LA4 delivers a clear, open, and uncluttered playback across the entire frequency range.

Instrumental overtones are rendered with exceptional precision and realism. Vocals are reproduced with outstanding accuracy and natural tones. Transients are fast and precise. Bass is deep and well controlled.

The ultra-linear phase response of the LA4, allows it to create a precise three-dimensional rendering of the recorded space. This space is open and uncluttered because noise and distortion are held below the 0-dB SPL threshold of hearing at all playback levels.

The LA4 may be the only preamplifier that meets or exceeds the transparency of Benchmark's AHB2 power amplifier and of Benchmark's DAC3 converter. In combination, these three components deliver the ultimate listening experience.

"Benchmark's LA4 is the widest-bandwidth, widest-dynamic-range, lowest-noise, lowest-distortion preamplifier I have encountered."

- John Atkinson, Stereophile Magazine

"By far, without question this is the best volume control I have ever encountered...

The LA4 has been widely tested with ... almost every tester reporting that the unit beats, often handily, any other ever tested in its product category, regardless of price."

- Paul Seydor, The Absolute Sound

"The Benchmark Media Systems LA4 preamplifier, AHB2 power amplifier, and DAC3 B are, individually, exceptionally transparent and well-designed audio devices. They are each top-shelf examples of their respective equipment categories in both measured and subjective performance."

- Carlo Lo Raso, Secrets of Home Theater and High Fidelity

On/Off Momentary Switch
IR Remote Sensor

Color Touch-Screen Display
Attenuation Shown in dB
Many Programmable Features

Long-Life Heavy-Duty Optical Encoder
0.5 dB per Step, 256 Steps

Input 1 - XLR (L,R)
Input 2 - XLR (L,R)
Input 3 - RCA (L,R)
Input 4 - RCA (L,R)

Left Out - XLR
Right Out - XLR
Mono Sum Out - XLR
Left Out - RCA
Right Out - RCA

Bidirectional Operation
Work with all Single and Dual Direction Trigger Ports
Time Delays Allow Noise-Free System Startup and Shutdown

Standard 3-Pin IEC Connector
Fuse Drawer with Two Fuses
Auto-Ranging
50-60 Hz

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Overall Score 94/100

Deliciously Crispy

Benchmark LA4 Line Amplifier — Transparent, ultra‑low‑noise linestage

Benchmark’s LA4 Line Amplifier is a compact, lab‑grade linestage built around ultra‑low noise and surgical transparency. Reviewers praise its reference‑class measurements and relay‑switched, 256‑step balanced volume for exceptional micro‑ and macro‑dynamics. Bass is tight and time‑correct, mids are revealing and lifelike, and the treble remains airy without glare, producing a wide, holographic soundstage ideal for critical listening. The solid metal chassis, touch‑screen setup and comprehensive balanced/unbalanced I/O make it a flexible partner for DACs and power amps. Suited to mastering, neutral‑system audiophiles, and those who want an honest signal path, the LA4 earns acclaim for translating recordings with minimal coloration while preserving musical engagement. See detailed impressions from Erich Wetzel, Gary L Beard, and Ken Redmond. Ultra‑low noise transparency and precise timing are its defining strengths.

The Audio Beatnik

"I agree with Benchmark and would add, that the Benchmark LA4 is simply the most transparent, least colored, and most revealing component I have had in my system to date."

Future Audiophile

"I was swept away by the musical transparency of the Benchmark LA4, by its freedom from high-frequency distortion, and by the increased engagement those qualities allowed."

SoundStage! Hi-Fi

"If those claims are true, and there’s no reason to believe they aren’t -- Benchmark gear has always performed as specified on the test bench -- the LA4 should be about as transparent-sounding a line-stage and headphone amp as you can find at any price."

SoundStage! Hi-Fi

"Benchmark Media Systems’ LA4 preamplifier presented an utterly realistic reproduction of what was contained on each recording I played through it -- and weak recordings stood out more than usual."

Positive Feedback

"My initial impression was simple: The LA4 preamp plays everything that is, and nothing that isn't...Neutrality in Audio... and that's really all this review needs to convey."

Pros

Reference‑grade transparency and extremely low noise floor, verified by measurements and multiple listening reports.
Precision relay‑switched, fully balanced 256‑step attenuator and intuitive touchscreen deliver very fine volume and channel‑balance control.
Wide‑bandwidth, well‑timed design yields tight, well‑integrated bass, clear mids and airy treble with exceptional imaging and soundstage depth.

Cons

Very revealing voicing — the LA4 exposes sibilance, compression or poor mixes rather than masking them, which can make flawed recordings sound harsh.
Remote is basic and some setup/advanced controls (balance, input naming, certain functions) require using the front touchscreen.
Function‑focused industrial design and no built‑in DAC, phono, or extensive DSP features—intended as a pure linestage rather than an all‑in‑one hub.

Transparency

96/100

Multiple reviewers praised the LA4's extremely low noise floor and utter neutrality: Positive Feedback called the noise floor "bats-strain-to-hear-it low," SoundStage Solo pointed to lab-level specs and said it should be "about as transparent-sounding ... as you can find at any price," and Future Audiophile stated "nothing is added, nothing is taken away." The measured specs (THD < -125 dB, SNR >135 dB, output noise <1.9 µV) and reviewers' listening reports consistently support a near-reference transparency rating.

Sound Quality

94/100

Dynamics

92/100

Consensus across reviews highlights strong dynamic performance: Positive Feedback noted "fast, furious dynamic swings" and "effortless slam," The Audio Beatnik reported relaxed low-level listening and preserved dynamic expression, and reviewers praised tight, well-timed bass impact. The LA4 preserves micro- and macro-dynamics very well in typical systems.

Soundstage Imaging

96/100

Several reviewers called out exceptional imaging and wide, deep staging: Future Audiophile said imaging and soundstaging were among the best they'd heard, The Audio Beatnik emphasized precise timing and a well-defined 3D stereo image, and Positive Feedback described a "cavernously wide stage." The consistent language across reviews supports a reference-grade imaging score.

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Build Quality

92/100

Reviewers described a compact but solid chassis with upscale-feeling panels and reliable thermal behavior (never warm). The LA4 features a fully balanced, relay-managed 256-step attenuator (per-channel attenuators with satisfying relay clicks), and the construction and internal design (internal universal supply, dense relay array) were praised for quality and engineering.

Features Connectivity

90/100

Well above baseline for an active preamp: the LA4 offers two balanced (XLR) and two unbalanced (RCA) inputs, balanced and unbalanced outputs, a balanced mono-sum output, 12V triggers, a front touchscreen (control of balance, soft/full mute, brightness), and a fully balanced relay attenuator. These capabilities (plus remote/IR sensor and balance control) put it in the fully featured 90–94 band.

Value for Money

93/100

Reviewers repeatedly called the LA4 competitively priced and good value for its performance: Positive Feedback called the $2495 MSRP "very competitive," SoundStage Solo and others recommended it as a rare combination of lab-grade specs and musical performance at that price, and Positive Feedback urged auditioning given its price-to-performance.