Frequency Response: 30 Hz to 15 kHz, -t 0.5 dB (Ref. 1 kHz,
0 dBu input level)
Phase Shift at 20 kHz: <28° (Ref. 1 kHz,
0 dBu input level)
Bandwidth (-3 dB): >50 kHz (Ref. 1 kHz,
0 dBu input level)
Insertion Loss: <1 dB {Ref. 1 kHz,
0 dBu input level).
Magnetic Shielding Effectiveness: >30 dB
Choices for Pad Types: H-pad or balanced-T with terminating resistor
Connector:
Type: Octal, male with centering post
Wiring: Pin 1 = input (-)
Pin 2 = circuit common Pin 3 = no connection Pin 4 = chassis ground Pin S - no connection Pin 6 = input (+) Pin 7 = output (+). Pin B -= output(-)
Dimensions: 1.6 in H x 1.6 in W x 2.0 in D 4.07 cm H x 4.07 cm W x 5.08 cm D
Color: Black
Weight: 3.16 oz (89.2 gr)
Support
Documentation: Equations to calculate resistor values for pads Table of pre-calculated resistor values for typical losses.

ARCHITECT'S AND ENGINEER'S SPECIFICATIONS

The accessory plug-in module shall include an input bridging transformer and printed circuit board with provisions for the installation of an internal resistive pad. The module shall be housed in an easy-to-open enclosure.
The transformer shall have a nominal primary impedance of 15 kSt, a turns ratio of 1:1, a frequency response within ±0.5 dB from 30 Hz to 15 kHz, a bandwidth in excess of 50 kHz, an insertion loss of less than 1 dB, a phase shift at 20 kHz of less than 28°, and a magnetic shielding effectiveness of more than 30 dB. In addition, the total harmonic distortion when driven below saturation shall not exceed 0.1% at 20 Hz and 0.01%, at 1 kHz.
The provision for the resistive pad shall accommodate "H" and "T" types of pads. A table of precalculated resistor values for typical losses shall be provided as a convenience.
The module shall be fully compatible with ALTEC LANSING's Anniversary Series power amplifier products. ' '
The accessory plug-in module shall be the ALTEC LANSING Model 15515A Input Bridging Transformer with Pad.