Audio Precision APx1701 Series, Installation Instructions Manual, Page: 32 / 44

Chapter : User’s Guide
14 APx1701 Transducer Test Interface: User’s Guide
Mounting and ventilation
The APx1701 is designed to mount in a standard 19-inch
relay rack, and is fitted with integral rack ears. The
APx1701 is two rack units (2 U) in height.
For proper ventilation to prevent overheating and failure,
we recommend that the APx1701 be mounted with at least
1 U of space above and below, and that there be at least 3
inches of space to the rear of the unit.
Never mount an APx1701 in a tightly enclosed rack.
Safety Features
The APx1701 monitors internal conditions to protect itself
and the device under test from damage.
If an amplifier channel trips its current limit and causes the
amplifier to voltage clip, an alert will be issued.
If the amplifier draw should exceed the capability of the
internal power supplies, the power supplies will momentar-
ily shut down and the amplifier inputs will be disconnected
by relays. The input relays can be reset from the APx500
software.
If thermal limits at key locations within the APx1701 are
exceeded, the amplifier inputs will be disconnected by
relays. The input relays can be reset from the APx500 soft-
ware.
LED indicators
There are two LED indicators on the APx1701 front panel.
The Power LED, to the right, is illuminated when AC mains
power is applied and the APx1701 is switched ON.
The USB LED, to the left, indicates a number of APx1701
conditions, detailed in the following table.
PC control and data interconnections
The APx1701 must be connected by USB 2.0 to a personal
computer running APx500 measurement software (version
4.3 or later) to operate.
If multiple APx1701 interfaces are detected, only the first
one encountered will be activated by the software.
APx audio interconnections
Typically, the APx instrument generator unbalanced audio
outputs are connected to the APx1701 amplifier inputs, and
the APx1701 microphone outputs (pass thru) are connected
to the analyzer balanced inputs. See System Connections on
page 16.
If impedance curves are to be measured, the Sense Resistor
output is connected to an analyzer balanced input.
Ground connection
For best noise performance, the APx1701 and the APx ana-
lyzer should have their ground lugs connected with a low-
USB LED Condition
• OFF • Power is Off, USB is not connected.
• ON • Power is On, USB is connected.
• Slow • Power is OFF, USB is connected
• Fast • A clip fault, a power fault, or a temperature
fault