Features Of The Aux-0025; Passive Design; Inductors; Connectors - Audio Precision AUX-0025 User Manual

Features of the AUX-0025

The AUX-0025 is a dual-channel passive low-pass filter specifically de-
signed to minimize switching amplifier carrier components while passing a
broad audio spectrum. This filter provides the signal preconditioning neces-
sary to accurately measure switching amplifier outputs using a wide-range
audio analyzer.

Passive design

For this application, a passive filter was determined to be the best ap-
proach. An active filter would require input attenuation and variable gain
to accommodate the wide range of signal amplitudes that might be ap-
plied, adding noise and distortion to the signal.

Inductors

Custom inductors were specified with an emphasis on power handling
and minimizing low-frequency distortion while satisfying the filter response
requirements.

Connectors

The AUX-0025 input connectors duplicate the balanced female
XLR-type and dual-banana jacks found on Audio Precision System 2000
Series instruments. A common connection is conveniently provided next to
each channel input. The common terminal will accept a banana plug or a
bare wire connection.
The filtered outputs of the AUX-0025 are provided on balanced male
XLR-type connectors.

Cables

For proper performance, the analyzer input impedance that the
AUX-0025 looks into must be high, with a maximum total capacitive load-
ing (including interconnecting cables) of 360 pF. Two short, low-capaci-
tance XLR-to-XLR cables are provided for the connection between the
AUX-0025 and the analyzing instrument to help ensure a proper loading.

Mounting

The AUX-0025 is fitted with resilient feet for tabletop use. It can also be
rack-mounted using the optional rack mount adapters available from Au-
dio Precision. Being a passive unit, the AUX-0025 does not dissipate ap-
preciable power and requires no extraordinary ventilation considerations.
AUX-0025 User's Manual
Features of the AUX-0025
Chapter 1: Introduction
3