Provides Exemplary Signal Path Between Inputs and Outputs: All-Analog Benchmark LA4 Line Preamplifier Boasts Off-the-Charts Precision, Low Noise, and 256-Step Volume Control
Designed to sit between a reference external DAC and power amplifier, the all-analog Benchmark LA4 line preamplifier aims to supply a peerless analog signal path between inputs and outputs. It achieves its maximum output power and sound pressure level without producing the distortion that traditionally accompanies increased output levels. Inside, relay gain control, relay input selection, relay muting, and gold-contact relays equate to incredibly quiet playback. A 256-step volume control complements a balance control while relay closures supply silky smooth volume changes. Two independent 256-step attenuators – one for the right channel, and one for the left channel – that operate in 0.5dB increments combine with a total 40 precision relays for the ultimate in control.
Tested and built in the U.S.A., LA4 exemplifies purity, speed, fidelity, and accuracy – and dead-silent backgrounds that will allow you to hear the pristine nuances, tonal textures, sustained notes, and wide-ranging dynamics that make music truly come alive. Its precision and silent operation are simply off the charts. Nothing short of benchmark quality.
You also may have noticed LA4 has an easy-access touchscreen and high-quality optical encoder on the volume knob. Re-nameable inputs (two balanced and two unbalanced), two bi-directional 12V trigger ports, a balanced stereo output, balanced mono sum output, and unbalanced stereo output augment premium casework with a milled faceplate and sides that join aluminum top, bottom, and rear panels. Benchmark's extended five-year manufacturer warranty and our 100% Satisfaction Guarantee give you further peace of mind.
"Its dynamic range is likewise at the highest state of the art. An amazing 256-step volume control maintains 0.5 dB/step resolution and flawless channel-tracking at any setting throughout its range. This is my new reference standard for a linestage."
– Paul Seydor, The Absolute Sound, Golden Ear Award
"The LA4 in combination with Benchmark's ABH2 amplifier constitutes [writer] Paul Seydor's standard for pre- and power amplifiers."
– The Absolute Sound, 2020 Product of the Year Award
All-Analog Signal Path, Incredible Speed and Precision
LA4 is entirely analog and designed to be driven from an external D/A converter or an external line-level analog source. It eclipses the performance of typical high-end preamplifiers by achieving much lower noise and distortion. The bandwidth of LA4 extends from 0.01Hz to more than 500kHz. This means LA4 delivers very precise amplitude and phase accuracy over the entire audio bandwidth. Wave shapes are accurately reproduced, and the entire spectrum delivered with precise timing. L4 produces musical overtones with lifelike accuracy, rendering musical instruments without changing their sonic character.
Wide-Ranging System Integration
LA4 is designed to work with the Benchmark DAC2 and DAC3 converters but may be driven from any high-end DAC. When paired with a Benchmark DAC, a single remote control will operate both units. LA4 makes a perfect complement to the Benchmark AHB2. It may be the only preamplifier or line amplifier that exceeds the signal to noise ratio of the ultra-quiet AHB2. This means LA4 will extract the full performance of AHB2. In contrast, other preamplifiers limit the system noise performance because they cannot match the SNR performance of AHB2. Two bidirectional 12V trigger ports can be used to link the LA4 with external DACs and power amplifiers. The trigger signal controls the power-up and power-down sequencing of the entire audio system. The trigger ports are compatible with most industry-standard trigger input or output ports, but can communicate bidirectionally with other Benchmark products.
Extra Convenient Features
LA4 includes independent on-screen mute buttons for the line outputs. They can also be muted with the volume knob or with the optional remote control. LA4 also comes with an on-screen -20dB dim button that instantly reduces the level by 20dB, providing a temporary volume reduction and an easy return to the previous listening level. This control makes it easy to transition between a normal listening level and a background level. Dim is also accessible from the optional remote control. Inputs may be renamed and unused inputs may be disabled. And input levels can be trimmed to provide input-to-input level matching. Screen brightness is adjustable and timers can be set to dim or shut off the display. The screen can be locked to prevent access to advanced features.
- Low-Noise Line Amplifier
- 256-Step Fully-Balanced Relay Gain Control, 0.5 dB Steps
- Precision Timed Relay Closures
- Precision Metal Film Resistors
- Gold-Contact Relays
- Balanced and Unbalanced I/O
- 0.01 Hz to 500 kHz
- SNR > 135 dB
- THD < 125 dB (0.00006%)
- Touch Screen Control
- IR Remote Control (optional)
- 2 Balanced Stereo Line Inputs
- 2 Unbalanced Stereo Line Inputs
- 1 Balanced Stereo Line Output
- 1 Unbalanced Stereo Line Output
- 1 Balanced Mono Sum Output
- 2 Bidirectional 12V Trigger Ports
> 135 dB, unweighted, 20-20 kHz
> 137 dB, A-weighted
- 0.003 dB at 10 Hz, -0.001 dB at 20 kHz
- 3 dB Bandwidth exceeds 0.1 Hz to 500 kHz
Output Impedance: 60 Ohms
Output Noise: < 1.9 uV at Unity Gain, 20-20 kHz
Maximum Input and Output Voltage: 20 Vrms (+28 dBu)
Crosstalk: < -133 dB @ 1 kHz, -116 dB @ 10 kHz
Typical Input Power: 12W
Maximum Input power: 17W
Standby Power: 0.33W
Dimensions (WHD): 8.65" x 3.88" x 8.33"
Weight: 8.0 lbs.
User Manual (PDF, 3.2 MB)