OPERATORS MANUAL
Model HPA Jr
Single Channel Headphone Amplifier
APPLICATIONS
The HPA Jr headphone amplifier is a compact , battery/external Vdc powered amplifier designed to interface your
favorite full-sized professional headphone to a variety of audio input sources. Now you won't be limited to small,
poor quality in-ear or "walkman" type headphones for your monitoring or listening needs. The HPA Jr will allow
you to drive headphones of many impedances to more than adequate listening levels with a full, rich sound not
obtainable at low output levels or with lightweight personal earpiece / headphones. You can use the HPA Jr for
such professional purposes as increased monitor levels from: mixers, portable VCR's, tape recorders or R-DAT's,
personal listening to keyboards and synthesizers or monitoring of home studio gear. You can have fun using an
HPA Jr to produce "concert hall" sound from your "walkman" type player, VCR, CD player or tape deck or from
any source with a headphone or line out signal.
FEATURES
Stereo/Mono Selector Switch: allows you to hear a monaural source in both ears or to "mono-up" a stereo (or two
channel) source.
Input Sensitivity Switch: allows selection of either -10dBm or-30dBm input levels so you can match the HPA Jr
to your input source.
Battery/External DC Operation: you can power the HPA Jr with either two 9 volt transistor radio type batteries
or with any 12-18 Volt dc source through the "EXT +12Vdc" 3.5mm jack.
Standard ¼" Tip/Ring/Sleeve (stereo) I/O Connectors: Both input and output connectors are the commonly
available ¼" TRS type... NO ADAPTERS NEEDED for most headphones!
Power Switch With LED Indicator: a convenient pushbutton switch for power on/off, along with a red LED
power on indicator.
Belt Clip: for convenient hands-free operation.
INSTRUCTIONS FOR USE
Battery Power: Install two 9 Volt batteries (Duracell MN1604 or equal) in the battery clips provided, using the
two polarized connectors. Access to the battery compartment is gained by removing the four phillips head screws
(two on the sides, two on the bottom) on the unit and sliding off the back cover. When the power switch is pressed,
the red LED will glow showing correct battery installation. Fresh battery life is approximately six hours of
continuous operation.
External DC Power: Connect a tip/sleeve (mono) 3.5mm plug to the "EXT +12Vdc" jack on the bottom of the
unit. IMPORTANT NOTE: Please observe proper polarity when using external power - the TIP of the plug should
be "+" and the SLEEVE "-". 12-18Vdc may be applied, either from external batteries or via an ac/dc converter like
the GOLD LINE model BE1. A switch in the jack disconnects the internal batteries when external Vdc is applied.
Input/Output Connectors And Gain Setting: Always begin with the HPA Jr sensitivity set to its lowest (-10dBm)
gain setting. (The sensitivity switch positioned AWAY from the red dot.) The sensitivity switch is located inside
the HPA Jr. For access to the sensitivity switch, see Battery Power above. Connect the input source to the INPUT
jack using a ¼" tip/ring/sleeve plug: TIP is left channel in, RING is right channel in and SLEEVE is
common/shield. Connect the headphones to the OUTPUT jack, again using a standard ¼" TRS plug (usually found
on most headphones). A slight rushing sound in the headphones when the power switch is depressed (with no input
signal applied) will indicate that the HPA Jr is functioning. With the level controls at their fullest counterclockwise positions (off), apply the input signal. Adjust the level controls for a comfortable listening/monitoring
level. If it is not possible to produce enough gain from the input source being used, turn the power off and reset the
sensitivity switch to -30dBm (red dot) position. Apply power and repeat adjustment of the level controls, always
beginning at the off (counter-clockwise) position to protect the headphones and your ears. The HPA Jr's high input
impedance allows you to connect it to a variety of sources without loading them, thus you can plug into the
headphone jack of most consumer equipment as well as the line out of tape decks, synths., and home studio
recording equipment. HELPFUL HINT: If your input source has its own output level or volume control, you can
use it to fine tune the resolution of the HPA Jr's level controls. Set the source's level/volume control to the point
where you can obtain the most comfortable control range (resolution) with the HPA Jr's level controls. Also use
any source level/volume control to trim the input to the HPA Jr to prevent overload distortion, especially if the
input signal exceeds -10dBm.
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SPECIFICATIONS
Frequency Response:.. 5Hz - 30kHz ± ¼dB
Nominal Impedance:... 50kΩ or higher
Output Impedance:..... 4Ω
Input Sensitivity:........ @1kHz for maximum output
(Selectable) -10dBm or 245mV
-30dBm or 25mV
Power Supply Output Z Output Power Output Voltage
Total Output Level:.... 12V 600Ω 120µΩ 6V
12V 8Ω 3W 3.5V
18V 600Ω 160mW 7V
18V 8Ω 5W 4.5V
Power Requirements:.. 12-18Vdc; internal batteries (2 @ 9V) or External
DC source
"Y'' Cable Hookup:.... HPA Jr will drive 2 headphones on a "Y'' cable but the
total load impedance should not be less than 8Ω.
Approvals: Emissions: - EN 55022 B - FCC Class B
Immunity: - EN 55024 B
This equipment has been tested and found to comply with the limits for a Class B digital device, pursuant to Part
15 of the FCC Rules. These limits are designed to provide reasonable protection against harmful interference in a
residential installation. This equipment generates, uses and can radiate radio frequency energy and, if not installed
and used in accordance with the instructions, may cause harmful interference to radio communications. However,
there is no guarantee that interference will not occur in a particular installation. If this equipment does cause
harmful interference to radio or television reception, which can be determined by turning the equipment off and
on, the user is encouraged to try to correct the interference by one or more of the following measures:
- Reorient or relocate the receiving antenna.
- Increase the separation between the equipment and receiver.
- Connect the equipment into an outlet on a circuit different from that to which the receiver is connected.
- Consult the dealer or an experienced radio/TV technician for help.
Pursuant to Part 15 of the FCC rules, any changes or modifications not expressly approved by Gold Line may cause
harmful interference and void the FCC authorization to operate the equipment.
WARRANTY and Factory Service
GOLD LINE products are proudly made in the USA and are covered by a one year limited warranty. For details of this
warranty, consult the enclosed warranty registration card or your local dealer.
GOLD LINE Customer Service will help you get the most from your new amplifier. For answers to questions regarding use of
the unit, or for information not covered in this manual, please write us. If you are experiencing difficulties with your amplifier,
please consult your dealer regarding factory service. If factory service is needed, you may call or fax us between 9:00am and
4:30pm US Eastern Time for instructions and a return authorization.
Enter your serial#_______________date of purchase_______________
12-431 m_hpajr_4g01.doc
Box 500 West Redding, CT. 06896 203-938-2588 phone - 203-938-8740 fax
http://www.gold-line.com Email - sales@gold-line.com
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