Specialists in “SOUND” Management
SIGTRONICS CORP. 949 N. Cataract Ave., #D, San Dimas, CA 91773 (909) 305-9399
INTRODUCTION
ATTENTION INSTALLER: To assure a trouble free
installation, please read the entire instructions
through once before beginning.
SPA-4S SYSTEM SPECIFICATIONS
CONFIGURATION -
The Sigtronics SPA-4S Intercom system is
specifically designed for permanent, panel mounted installation
in aircraft. The SPA-4S provides voice activated (VOX) intercom
and music input for up
to four headset positions in a small single
chassis unit.
UPGRADE -
A SPA-4S can upgrade an existing SPA-400
installation requiring minimal re-wiring.
STEREO MUSIC INPUT -
Music input accepts standard port-
able music headphone or line level outputs. Automobile
Speaker level outputs can be adapted for use with SPA-4S sys-
tems.
COMPATIBILITY -
Sigtronics SPA-4S intercoms have been
designed to operate with all standard general aviation aircraft
radios and headsets.
SIZE:
Panel 1" x 2.5". Chassis - 1" high x 2.5" wide x 4" deep.
Can be mounted either horizontally or vertically in the aircraft
panel.
WEIGHT:
5.5 ounces (SPA-4S intercom unit with panel and
knobs). Jacks and wiring harness weigh 7.0 ounces
INPUT POWER:
11VDC through 32VDC. Maximum current
drain 0.11 Amps
DISTORTION:
Less than 1% total harmonic distortion.
WARRANTY:
SPA-4S intercoms are constructed of high quality
components and carry a five year parts and labor warranty.
MADE IN THE USA
HARDWARE SUPPLIED
Besides the intercom unit and instructions, each SPA-4S sys-
tem comes with the following hardware:
Headphone Output Jacks - Accept standard 0.250"
aircraft stereo headphone plugs.
4
Microphone Input Jacks - Accept standard 0.206"
aircraft microphone plugs. (U93 plug compatible
jacks can be used in place of the jacks provided –
monaural installations only).
4
Mic Jack Insulating Washers, Flat
4
Mic Jack Insulating Washers, Shoulder
4
Intercom Panel - lettered on both sides.
1
Intercom Control Knobs
2
Mounting Screws 4-40 x 1/2
2
Drill Template - Adhesive backed hole size pattern
for drilling aircraft panel.
1
Intercom/Aircraft Interface Cable (4 feet long)
1
Headphone/Music Interface Cable (4 feet long)
1
Stereo music input jack 3.5mm
1
MUSIC MUTE OPTIONS
FACTORY DEFAULT - PARTIAL MUSIC MUTE DURING ICS -
When listening to music and someone speaks on the intercom
the default factory operation is to partially mute the music so
you can hear the conversation. The SPA-4S intercoms have two
options that can be enabled if desired. These options are en-
abled with the intercom removed from the aircraft.
OPTION "A" - FULL MUSIC MUTE DURING ICS
- The music
can be completely muted during intercom conversations. To
enable this option, small jumper wires are installed on the solder
side of the circuit board.
OPTION "B" - NO MUSIC MUTE DURING ICS
- The music will
not be muted during intercom conversations. To enable this
option, circuit traces are cut on the solder side of the circuit
board.
NOTE - During radio transmission and reception, the music will
always be fully muted. This is for communication safety rea-
sons.
HIGH NOISE VERSION
Model SPA-4SN –
The “N” version of the SPA-4S has all the
above features but is specifically configured for very high noise
SPA-4S INSTALLATION INSTRUCTIONS
