GRAS 26AJ 1/2'' SysCheck Preamplifier with integrated connector

Freq range: 2.5 Hz - 200 kHz
Noise: 1.8 µV
Gain: -0.35 dB
Special feature: SysCheck

Technology

Typical applications and use

Precision measurements

Low-pressure measurements

General-purpose preamplifiers

Design

All GRAS microphone preamplifiers are based on a small ceramic thick-film substrate with a very high input impedance. The ceramic substrate is shielded by a guard ring to minimise the influence of stray capacitance and microphonic interference. The casing is made of stainless steel for maximum strength and durability. The small dimensions of the 26AJ ensures reliable operation under humid conditions owing to the heat generated by internal power dissipation. A 1/4" alternative is available, GRAS 26AL.

GRAS 26AJ has SysCheck for easy remote verification of the measurement chain. It allows you to send a test signal to an RC network in the preamplifier. This signal is applied to pin 1 of the 7-pin LEMO cable/connector. SysCheck does not result in a signal proportional to the microphone’s sensitivity, but it gives you a way to determine whether your system is stable. SysCheck cannot replace a proper acoustic calibration of the microphone.

Compatibility

The  preamplifier is compatible with 1/2" microphones as defined in international standard IEC1094 Measurement Microphones, Part 4: Specifications for working standard microphones. The mounting thread (11.7 mm - 60 UNS-2) is compatiblewith other available makes of similar microphone preamplifiers.

Connector

26AJ has an integrated 7-pin LEMO series 1B connector.

7-pin LEMO 1B male (ext. view)

Specifications

Frequency range (±0.2 dB) with 18 pF microphone dummy
Hz
2.5 to 200 k
Slew rate
V/µs
20
Input impedance
GΩ // pF
20 // 0.4
Output impedance
Ω
75
Output Voltage Swing, max. @ ±14V/+28V power supply
Vp
12
Output Voltage Swing, max. @ ±60V/+120V power supply
Vp
50
Noise (A-Weighted) max.
µV
2.5
Noise (A-Weighted) typ.
µV
1.8
Noise (Linear 20 Hz – 20 kHz) max.
µV
6
Noise (Linear 20 Hz – 20 kHz) typ.
µV
3.5
High-pass filter @3dB cut-off
Hz
TBD
Gain
dB
-0.35
Power supply, single
V
28 to 120
Power supply, balanced
V
±14 to ±60
DC-offset, min., single suppy
V
0.5 x Vs - 1
DC-offset, max., single suppy
V
0.5 x Vs + 4
DC-offset, balanced supply
V
-1 to 4
Temperature range, operation
°C / °F
-30 to 70 / -22 to 158
Temperature range, storage
°C / °F
-40 to 85 / -40 to 185
Humidity range non condensing
% RH
0 to 95
Connector type
7-pin LEMO (FGG.1B.307)
CE/RoHS compliant/WEEE registered
Yes / Yes, Yes
Weight
g / oz
35.0 / 1.24
Specification Conditions

Conditions: 23 °C Ambient temperature, ±60V/+120V power supply, 18 pF dummy microphone, 3 m output cable.

Low frequency response for various microphone capacities

Max. RMS output signal for various cable loads with 120 V supply

GRAS Sound & Vibration reserves the right to change specifications and accessories without notice.

Dimensions

Ordering info

Optional items

GRAS AA0008

3 m LEMO 7-pin - LEMO 7-pin Cable

GRAS AA0020-CL

Customized Length LEMO 7-pin - LEMO 7-pin Cable

GRAS AL0008

1/2" Microphone Holder, POM

GRAS AL0012

1/2" Microphone Holder, Stainless Steel

GRAS AL0005

Swivel head

GRAS AL0006

Tripod

GRAS RA0019

Adapter for 1/4" microphone and 1/2" preamplifier

GRAS RA0073

Adapter for 1" microphone and 1/2" preamplifier

GRAS RA0190

Right-angled (90º) Adapter for 1/2" Microphone and 1/2" Preamplifier

GRAS RA0016

20 dB Attenuator for externally polarized 1/2" microphones

GRAS RA0062

20 pF Preamplifier-input Adapter for 1/2" preamplifiers

GRAS 12AA

2-Channel Power Module with gain, filters and SysCheck generator

GRAS 12AQ

2-Channel Universal Power Module with signal conditioning and PC interface

 GRAS Sound & Vibration reserves the right to change specifications and accessories without notice.

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