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GENERAL

The ILP-1 is a high-clipping level, low-noise preampli-

fier designed exclusively for use with Shure Models
SM90A, SM91A, SM98A, SM102B and SM102W, or for
use as a replacement preamplifier for older Models SM90,
SM91, and SM98. The ILP-1 connects to balanced micro-
phone inputs providing 11 to 52 Vdc phantom power. Two
switches on the ILP-1 allow you to set low-frequency re-
sponse (flat or rolloff at 12 dB/octave) and gain (0 or +10
dB). The low cut switch minimizes ambient low-frequency
noise from sources such as heating or air conditioner
fans.

The supplied mounting clamps hold the preamplifier in

place for permanent installations. Use either one or two
clamps depending on location and application.

SPECIFICATIONS

Frequency Response

Switch Setting

Gain (dB)

Flat

30 Hz to 20 kHz 

(6 dB/octave rolloff below 30 Hz)

Rolloff

80 Hz to 20 kHz 

(12 dB/octave rolloff below 80 Hz)

Gain (at 1 kHz, no load)

Switch Setting

Gain (dB)

0

–6.0 (

±

0.5 dB)

+10

+4.0 (+1.0, –1.5 dB)

Output Impedance

Rated at 150 

 (90 

 actual)

Output Noise (V

in

, grounded, no load)

–123 dBV rms typical, A-weighted

Output Clipping Level

GAIN SWITCH

LOAD

0

+10

150 

0.0 dBV

–7.0 dBV

800 

–13.0 dBV

–21.0 dBV

Electromagnetic Hum Sensitivity

–146 dBV equivalent in 1 millioersted field

Electrostatic Hum Pickup

–97 dBV typical, measured in 12 kV field

Polarity

Positive voltage on pin 3 relative to pin 1 of the input
connector produces positive voltage on pin 2 relative to
pin 3 of the output connector

Power Requirement

Phantom power: 11 to 52 Vdc at pins 2 and 3 relative
to pin 1

Dimensions

See Figure 1.

138 mm

(5 7/16 IN.)

20 mm

(13/16 IN.)

DIMENSIONS

FIGURE 1

Weight

170 grams (6.0 ounces)

Connectors

Input: mini 3-pin male (TB3M)

Output: 3-pin (male) XLR-type

Switches

Two recessed slide switches 
(low frequency rolloff and 0/+10 gain)

Case

Steel, matte black enamel finished

Environmental Conditions

Operating Temperature: –19 to 57

°

 C (–20 to 13

°

 F)

Storage Temperature: –29 to 74

°

 C (–20 to 168

°

 F)

Relative Humidity: 0 to 95%

Model ILP-1 User Guide

27A8494  (Rev. 1)

E

2002, Shure Incorporated

Printed in U.S.A.

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