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Benchmark HPA4 Headphone Amplifier


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Enquiry/price check? Click here SKU: BDNHPA4
Ex VAT: £2,749.17

HPA4 delivers power, fidelity, speed and accuracy over an utterly silent background; a perfect compliment to the Benchmark AHB2.

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Warranty length 2 Years
Brand Benchmark

Tech Specs

Headphone Out
- THD < -125 dB (0.00006%)
- SNR > 131/135dB, (UWTD, AWTD)
- Freq Resp: 0.003/0.001dB @10/20k Hz
- 3dB Bandwidth exceeds 0.1Hz-500kHz
- Output Impedance: near 0 Ohms
- Noise: < 2.45 uV (Unity Gain) 20-20kHz
- Max Out Power: 6W into 16O, 1.5 A
- Max Out Voltage: 11.5Vrms into 300O
- Crosstalk: <-133/-115dB, @1/10kHz (XLR4)


Balanced Line Out
- THD: <-125dB (0.00006%)
- SNR: >135/137dB (UWTD, AWTD)
- Freq Resp: -0.003/0.001dB @10/20k Hz
- 3dB Bandwidth exceeds 0.1Hz-500kHz
- Output Impedance: 60 Ohms
- Noise: <1.9uV (Unity Gain) 20-20kHz
- Max In/Out Voltage: 20Vrms (+28 dBu)
- Crosstalk: <-133/-116dB, @1/10kHz


- Power: 18/35/0.33W, Typ/Max/Stndby
- Internal Universal Power Supply
- Dimensions (WHD): 8.65" x 3.47" x 8.33"
- Weight: 8.0lbs

Product Description

Benchmark HP-A4 Headphone Amplifier with Achromatic Audio Amplifier technology is Benchmark's top-of-the-line reference amplifier. Th HP-A4 reduces distortion and noise for fatigue-free listening sessions. A wide bandwidth allows for an exceptionally precise and accurate musical presentation. This is truly the flagship of Benchmark audio.

Precision relays

The HP-A4 includes the ultimate relay gain control. With 64 precision relays including relay input selection and relay muting and relay closures to ensure volume changes are delivered smoothly and absolute precision concurs. 

Ultimate speed and precision

Expect the ultimate speed and precision with the HPA4 with an audio bandwidth extending from 0.001 Hz to over 500 kHz, With a bandwidth like this, this headphone amplifier is able to deliver exceptional amplitude precision and phase accuracy over the whole audio bandwidth. Timing is precise, wave shapes are accurate and overtones are enjoyed with life-like feelings. Enjoy the sound of every musical instrument conveying its true sonic character.

Power and protection to every headphone

The HPA4 incorporates the flagship THX-888 amplifier design which uses the revolutionary THX-888 AAA technology to drive high voltage to the most sensitive headphones and high power and current to the most demanding low-impedance headphones. It delivers 11.9 Vrms into 300 Ohms and 6 watts into 16 Ohms. Special attention is paid to protecting high-end headphones and the amplifier itself by incorporating such systems as short circuit detection, DC detection, over-voltage protection, over current protection and thermal protection.

Maximum Output Power

The HPA4 is a strictly analog amplifier, designed to provide a 100% analog signal path between inputs and outputs when driven from an external DAC or analog source. It also features balanced and unbalanced stereo outputs, and headphone output featuring a 1/4" TRS and a 4-pin XLR. The HPA-4 headphone amplifier is able to reach its optimum output power and SPL without the distortion that often accompanies elevated output levels in traditional amplifiers.

Key Features

- Easy access touch screen feature for selecting input level offsets, input names, balance control, screen dimming, function locking and remote control
- Rotary Encoder for easy volume control between steps
- Mute the headphone and line outputs with independent on-screen mute buttons, volume knob or remote control
- On screen and remote controlled -20db dim function for returning to previous listening level and temporary volume reduction
- Aluminium milled casing in black and white options

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Contact Details

UK Local Rate Number
0844 50 403 50

Sales Landline
0121 224 7300/7401

Customer Services Landline
0121 224 7350/7351

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