About Us
The Professional's Source Since 1973
  • Help
  • 800.606.6969
Hello, Log InAccount & Orders
My Cart
Video Chat with a Pro Audio Expert - Live

Benchmark HPA4 Rackmount Reference Headphone/Line Amplifier with Remote Control (Black)

BH #BEHPA4RRB • MFR #500-17200-203
Benchmark HPA4 Rackmount Reference Headphone/Line Amplifier with Remote Control (Black)
Key Features
  • THX-888 Headphone Amplifier
  • High Voltage, Current, and Power
  • Low Distortion, Noise, and Crosstalk
  • 256-Step Balanced Relay Gain Control
The black Benchmark HPA4 is a 2 RU rackmount reference headphone/line amplifier designed to deliver pristine amplification of analog sources for audiophiles, mixing and mastering engineers, and music aficionados in homes, recording studios, and mastering suites. Resulting from Benchmark's collaboration with THX, the HPA4 features a THX-888 headphone amplifier for an output signal with high voltage, current, and power complemented by low distortion, noise, and crosstalk. Designed, assembled, and tested in the USA, it boasts a sturdy brushed aluminum housing with a milled faceplate and milled sides.
Special Order
Expected availability: 2-4 weeks
$3,799.00
$317/mo. suggested payments for 12 Mos.
with the credit card.§ 
or Save the Tax with the credit card.‡ 

Important Notice

  • This item is noncancelable and nonreturnable.
Protect Your Gear
Add a protection plan from $439.99
Configuration
Rackmount Faceplate
Standard Faceplate
Color
Black
Silver
Remote Control
No Remote Control
With Remote Control
Ask Our Experts
800.606.6969

Benchmark HPA4 Overview

  • 1Description
  • 2THX AAA Technology
  • 3Line Amplification
  • 4100% Analog Signal Path
  • 5High Voltage, High Current, and High Power
  • 6Speed and Precision
  • 7Balanced and Unbalanced I/O
  • 8Touchscreen
  • 9Rotary Encoder
  • 10Trigger Ports
  • 11Convenience Features
  • 12Sleek and Sturdy Construction

The black Benchmark HPA4 is a 2 RU rackmount reference headphone/line amplifier designed to deliver pristine amplification of analog sources for audiophiles, mixing and mastering engineers, and music aficionados in homes, recording studios, and mastering suites. Resulting from Benchmark's collaboration with THX, the HPA4 features a THX-888 headphone amplifier for an output signal with high voltage, current, and power complemented by low distortion, noise, and crosstalk. Designed, assembled, and tested in the USA, it boasts a sturdy brushed aluminum housing with a milled faceplate and milled sides.

The rear-panel I/O includes two balanced stereo XLR inputs, two unbalanced stereo RCA inputs, XLR and RCA stereo outputs, and a mono XLR output. The front-panel offers two headphone outputs, one unbalanced 1/4" TRS jack and one balanced XLR 4-pin jack. Volume adjustments are executed via the 256-step balanced relay gain control, which uses increments of 0.5 dB. The integrated touchscreen and supplied remote control allow convenient access to common functions such as input selection, dim, mute, and more. Built-in protection systems guard against potential damage from DC, short-circuit, over-current, over-voltage, and thermal issues.

 

THX AAA Technology
The collaboration between Benchmark and THX features THX Achromatic Audio Amplifier (AAA) technology, which reduces harmonic, intermodulation, and crossover distortion by 20 to 40 dB to guarantee a realistic and fatigue-free listening experience. It accomplishes this using a patented feed-forward topology to null conventional distortion and noise mechanisms, resulting in extreme linearity. THX AAA allows the amplifier to reach its maximum output power and sound pressure level without producing the distortion that normally accompanies increased output levels in traditional amplifiers.
Line Amplification
The THX-888 amplifier is driven by a Benchmark line amplifier that features relay gain control, relay input selection, and relay muting. The line amplifier incorporates premium gold-contact relays. The gain control has 256 steps in 0.5 dB increments. It also features a balance control. Relay closures are precisely timed to deliver smooth volume changes. The HPA4 includes four independent 256-step attenuators: two for the headphone outputs and two for the line outputs. To make this all happen, the HPA4 includes a total of 64 precision relays.
100% Analog Signal Path
The HPA4 is 100% analog and should be driven from an external D/A converter or analog source. It eclipses the performance of typical high-end preamplifiers by achieving much lower noise and distortion.
High Voltage, High Current, and High Power
The THX-888 amplifier can cleanly deliver high voltage into low-sensitivity, high-impedance headphones and it can cleanly deliver high power and current into low-impedance headphones. The HPA4 delivers 11.9 Vrms into 300 Ohms and 6W into 16 Ohms. Given these extreme capabilities, Benchmark has incorporated several protection systems to protect expensive headphones and the amplifier itself. These include DC, short-circuit, over-current, over-voltage, and thermal protection.
Speed and Precision
The bandwidth of the HPA4 extends from 0.01 Hz to over 500 kHz with a drop of only 3 dB. The 10 Hz to 20 kHz spectrum boasts a maximum variance of only -0.003 dB. 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.
Balanced and Unbalanced I/O
The headphone output of the THX-888 amplifier features a 1/4" TRS and an XLR 4-pin. While both outputs deliver the full performance of the HPA4, the XLR4 is most ideal due to its lower contact resistance. The HPA4 features two balanced stereo inputs via XLR 3-pin jacks and two unbalanced stereo inputs via RCA jacks. The line amplifier provides one balanced stereo output, one balanced mono sum, and one unbalanced stereo output.
Touchscreen
The touchscreen 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.
Trigger Ports
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.
Convenience Features
The HPA4 includes independent on-screen mute buttons for the headphone and line outputs. Both can also be muted with the volume knob or with the supplied remote control. An on-screen -20 dB dim button instantly reduces the level by 20 dB, 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. The dim function is also accessible from the 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.

Sleek and Sturdy Construction
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 HPA4 was designed, assembled, and tested in the USA.

Benchmark HPA4 Specs

Key Specs
Number of Headphone Channels
Single Channel
Headphone Output Power
6 W into 16 Ohms (Max)
Analog Audio I/O
2 x XLR 3-Pin Balanced Output (1 Stereo Pair)
1 x XLR 3-Pin Balanced Mono Output
1 x Stereo RCA Coaxial Unbalanced Output
1 x XLR 4-Pin Balanced Headphone Output
1 x 1/4" TRS Unbalanced Headphone Output
4 x XLR 3-Pin Balanced Input (2 Stereo Pair)
2 x Stereo RCA Coaxial Unbalanced Input
Frequency Response
0.1 Hz to 500 kHz -3 dB
10 Hz to 20 kHz -0.003 dB
Power Requirements
AC Input
Number of Headphone Channels
Single Channel
Headphone Output Power
6 W into 16 Ohms (Max)
Display
Touchscreen
Connectivity
Analog Audio I/O
2 x XLR 3-Pin Balanced Output (1 Stereo Pair)
1 x XLR 3-Pin Balanced Mono Output
1 x Stereo RCA Coaxial Unbalanced Output
1 x XLR 4-Pin Balanced Headphone Output
1 x 1/4" TRS Unbalanced Headphone Output
4 x XLR 3-Pin Balanced Input (2 Stereo Pair)
2 x Stereo RCA Coaxial Unbalanced Input
Other I/O
2 x 1/8" / 3.5 mm TRS 12 V Trigger (Bi-Directional)
Performance
Frequency Response
0.1 Hz to 500 kHz -3 dB
10 Hz to 20 kHz -0.003 dB
Maximum Input Level
+28 dBu
Maximum Output Level
Line Outputs:
+28 dBu
Headphone Outputs:
11.5 Vrms (300-Ohm Load)
Impedance
Line Outputs:
60 Ohms
Headphone Outputs:
< 1 Ohm
THD+N
< -125 dB / 0.00006%
SNR
Line Outputs:
> 135 dB (Unweighted, 20 Hz to 20 kHz)
> 137 dB (A-Weighted)
Headphone Outputs:
> 131 dB (Unweighted, 20 Hz to 20 kHz)
> 135 dB (A-Weighted)
Noise
Line Outputs:
< 1.9 µV (Unity Gain, 20 Hz to 20 kHz)
Headphone Outputs:
< 2.45 µV (Unity Gain, 20 Hz to 20 kHz)
Crosstalk
Line Outputs:
< -133 dB (1 kHz)
< -116 dB (10 kHz)
Balanced Headphone Outputs:
< -133 dB (1 kHz)
< -115 dB (10 kHz)
Power
Power Requirements
AC Input
AC Input Power
100 to 240 VAC, 50 / 60 Hz
Power Consumption
18 W (Typical)
35 W (Maximum)
0.33 W (Standby)
Physical
Rackmount Size
2 RU
Dimensions
19 x 3.9 x 8.3" / 48.3 x 9.9 x 21.2 cm (with Feet)
19 x 3.5 x 8.3" / 48.3 x 8.8 x 21.2 cm (without Feet)
Weight
9.0 lb / 4.1 kg

Benchmark HPA4 Reviews

See any errors on this page? Let us know