THE ULTIMATE LINE AMPLIFIERS

The LA4 and HPA4 are the ultimate line amplifiers for professional applications. They features balanced and unbalanced inputs and outputs. They include fully-balanced high-precision 256-step relay controlled gain stages. The gain range is -112 dB to +15 dB in 0.5 dB steps. The relay closures are precisely timed to provide silky-smooth volume changes. They also include relays for mute, balance, input selection, and -20 dB dim.

The LA4 and HPA4 line amplifiers are an excellent choice for controlling the levels to studio monitors, and power amplifiers in the most critical listening environments. No other analog-to-analog line amplifiers offer higher performance!

Benchmark Line Amplifier defines the current state of the art:

• THD < -125 dB (0.00006%)
• SNR > 135 dB, unweighted, 20-20 kHz
• SNR > 137 dB, A-weighted
• Frequency Response - 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 Level, +28 dBu
• Crosstalk < -133 dB @ 1 kHz, -116 dB @ 10 kHz
• Gain Range -112 to +15 dB in 0.5 dB steps

• The Ultimate Line Amplifier

  The THX-888 amplifieris driven by a Benchmark line amplifier that features relay gain control, relay input selection, and relay muting. The line amplifier incorporates the finest gold-contact relays available. The gain control has 256 steps in 0.5 dB increments. It also features a balance control. Relay closures are precisely timed to deliver silky-smooth volume changes. No other relay gain control offers this level of precision and performance.

  100% Analog Signal Path

  The LA4 is 100% analog. It is designed to be driven from an external D/A converter or an external analog source. The HPA4 is designed to provide the ultimate analog signal path between inputs and outputs. The LA4 eclipses the performance of typical high-end preamplifiers by achieving much lower noise and distortion.

   

  Speed and Precision

  The bandwidth of the HPA4 extends from 0.01 Hz to over 500 kHz. This means that the HPA4 delivers very precise amplitude and phase accuracy over the entire audio bandwidth. Wave shapes are accurately reproduced, and the entire spectrum is delivered with precise timing. The HPA4 will deliver musical overtones with life-like accuracy. This means that musical instruments are rendered without changing their sonic character.

  The LAA4 features two balanced stereo inputs and two unbalanced stereo inputs. The line amplifier provides one balanced stereo output, one balanced mono sum, and one unbalanced stereo output.

   

• System Integration

  The LA4 includes IR remote control and can be operated using the optional Benchmark remote. The LA4 is designed to work with the Benchmark DAC2 and DAC3 converters but may be driven from any high-end D/A converter. When paired with a Benchmark DAC, a single remote control will operate both units.
  
  The LA4 is the 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 that the HPA4 will extract the full performance of the AHB2. In contrast, other preamplifiers limit the system noise performance because they cannot match the SNR performance of the AHB2. The LA4 is the only line amplifier/preamplifier that we recommend inserting between a DAC and the AHB2. The LA4 can be inserted between a Benchmark DAC3 and AHB2 without degrading the system noise performance. With the LA4 inserted, the DAC3's 32-bit digital gain control is replaced by the LA4's more-resolving fully-analog relay gain control.
  
  Two bidirectional 12V trigger ports can be used to link the HPA4 with external D/A converters 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.

  Touch Screen

  The touch screen provides easy access to advanced features such as balance control, input level offsets, input names, screen dimming, remote control, and function locking. Help screens explain the special functions.

  Rotary Encoder

  The volume control knob features a high-quality optical encoder that is rated for heavy use. An acceleration feature makes it easy to move through the 256 volume steps while maintaining 0.5 dB/step resolution. A press of the control knob toggles between headphone volume, line out volume, or both.

  Convenience Features

  The LA4 includes independent on-screen mute buttons for the headphone and line outputs. Both can also be muted with the volume knob or with the optional remote control.
  
  The LA4 includes an on-screen -20 dB dim button that instantly reduces the level by 20dB. This function provides 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. The dim function is also accessible from the optional remote control.
  
  Inputs may be renamed and unused inputs may be disabled. 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.

  Casework

  The LA4 is available with a black or silver faceplate and is designed to match the Benchmark AHB2 power amplifier. It occupies the same footprint as the Benchmark DAC1, DAC2 and DAC3 converters. The case features a milled faceplate and milled sides. Top, bottom, and rear panels are made from thick aluminum and feature a brushed texture. The LA4 is built to last and will be a fine addition to your listening space.