Instruction Manual for HPA4 with 1.0.X Firmware – REV B Page 25
lack these stages which remove the common-
mode distortion produced by D/A chips.
Powerful Headphone Output
The THX-888 amplifier in the HPA4 can
cleanly deliver high power and current into
low-impedance headphones. It can also
deliver the high voltage required by very low-
sensitivity headphones.
High Power
The HPA4 delivers 6 Watts into 16 Ohms.
Best of all, there is no increase in THD when
driving low-impedance headphones. The THX
AAA™ technology keeps the output distortion
free while driving very difficult low-impedance
loads.
High Current
Low-impedance headphones may also require
high current due to difficult phase angles
presented by non-resistive driver loading. The
HPA4 can provide peak currents exceeding
1.5 amps. This is more than enough current
to drive difficult headphones with ease.
High Voltage
High-impedance headphones may not draw
much power or much current, but they may
demand high drive voltages. The HPA4
delivers 11.9 Vrms into 300-Ohm
headphones. This is plenty of voltage to drive
headphones with very low sensitivities.
Dual Headphone Outputs
The HPA4 features a traditional 1/4" TRS
headphone jack and a 4-pin XLR jack.
The 4-pin jack provides separate returns for
the left and right channels. Each output
channel is driven differentially relative to its
return pin on the 4-pin jack.
We recommend using the 4-pin jack because
the XLR connector provides lower contact
resistance than the TRS connector.
Ultra-Wide Bandwidth
The frequency response of the HPA4 extends
from 0.1 Hz to 500 kHz. This extended range
keeps the phase response extremely accurate
over the entire audio band. The entire audio
spectrum is delivered with the proper timing.
Bass is delivered with the correct timing
relative to other frequencies. Most audio
products deliver the bass slightly late. Bass
that arrives late tends to mask high-
frequency details. In contrast, bass that
arrives with the correct timing will sound
deep, full and well damped. For this reason,
all Benchmark products feature low-frequency
extension to 0.1 Hz.
The extreme 500 kHz high-frequency
extension delivered virtually perfect timing at
the high end of the audio spectrum. High
frequencies are delivered with precise timing
relative to low and mid frequencies. In
addition, the left-right differential phase is
virtually perfect at 20 kHz. These timing
characteristics preserve the precise placement
of voices within a well-defined 3D stereo
image.
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 volume, or both.
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 optional remote
control.
The HPA4 includes an on-screen -20 dB dim
button that fades the level down by 20dB.
This function provides a temporary volume
reduction and an easy return to the previous
To Next Page
Loading...
