Benchmark HPA-2 Quick Start Manual

Specs
Input Stereo 200 kΩ Balanced Inputs
Input Clip +26.5 dBu with ±15 volt supplies
Output Stereo, for use with 1/4" Tip/Ring/Sleeve plugs only, other panel
connectors may be wired to the amplifier by way of on-board output
connectors
Output Impedance "0 Ω"
Output Clip Dependant upon power voltage and load [+20 dBu @ ±15V and 60 Ω
load]
Load Impedance 30 Ω or higher
Output Level Up to +20 dBu into 60 Ω [dependent upon power source]
Output Control Dual log taper response
Gain Range Off to +20 dB
Bandwidth 0.1 Hz to 300 kHz minimum
THD+N 0.0003% typical at headphone inputs - under load!
Noise Floor Better than -75 dBu at maximum gain
Power (Bipolar) ± 9 to ± 18 volts, maximum peak current needed = 1.1
Amp at maximum peak output into 30 Ω
Peak Output 7.5 watts [±18 volt supplies. 30 Ω load]
Max Avg Output 1.35 watts [-8 dB peak to average ratio]
Amplifier Board Length behind panel = 3.760", width = 1.335", mounting hole
diameter = 0.437" [7/16"]
Gain Ctrl Board Length behind panel = 1.025", width = 1.335", mounting hole
diameter = 0.275" [J drill or 9/32 (0.281)], shaft length = 0.385",
shaft diameter. = 0.235" [16-star spline]
Spacing Minimum spacing between Gain Control Board mounting hole and
1/4" jack = 7.5"
Minimum spacing between Amplifier Board and Gain Control Board =
0.75" [both boards mounted vertically], Maximum panel thickness =
0.1". Knob diameter = 0.75", length = 0.75"
Knob Volume control knob included
HPA-2 Instruction Manual, Revision 1
Copyright © 2006 Benchmark Media Systems, Inc.
All rights reserved.
Benchmark Media Systems, Inc.
5925 Court Street Road
Syracuse, NY 13206-1707 USA
+1-315-437-6300, FAX +1-315-437-8119
1-800-BNCHMRK (1-800-262-4675)
benchmarkmedia.com
Audiophile Grade Stereo Headphone Amplifier Module
The Benchmark HPA-2 is a high-power audiophile-grade stereo
headphone amplifier module that can be mounted in virtually any
location. One of the most popular uses of the HPA-2 is with custom
constructed radio talk show round tables. The HPA-2 features sonic
purity that fulfills even the most demanding headphone applications.
The HPA-2 is designed to power all headphones that have a load
impedance of 30 Ω or higher. It is not designed to power headphones
that have 8 Ω load impedance.
The HPA-2 requires a bipolar power supply using voltages from a
recommended minimum of ±9 volts to an absolute maximum of
±18.7 volts. The higher the power supply voltages the higher the
possible output level from the headphones. The higher the output
current from the external power supply the greater the number of
HPA-2s and headphones that may be used in the system.
HPA-2