Benchmark LA4 Line Amplifier

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