The GRAS 26CT 1/4" Preamplifier is a very small preamplifier optimized for use with prepolarized condenser microphones. It is a robust unit and uses a CCP power supply. It has a very low inherent noise level, a large dynamic range and a frequency response from below 2 Hz to above 200 kHz.
Technology
Typical applications and use
- Confined spaces
- High-frequency measurements
- High-pressure measurements
- Sound intensity measurements
- Near-field measurements
- Anechoic boxes
- Hearing-aid measurements
Design
Its small ceramic thick-film substrate has a very high input impedance, and is shielded by a guard ring to minimise the influence of stray capacitance and microphonic interference.
The 26CT is delivered with Generation II TEDS. The calibration data is programmed into the built-in TEDS according to IEEE 1451.4 using UDID I27-0-0-0U. If your measurement platform supports Transducer Electronic Data Sheets you will be able to read and write data like properties and calibration data.
Generation II TEDS chip (DS2431) may require updated system software.
It can be used with GRAS 40BE and 40BD 1/4" and 40AE, 40AD and 40AQ 1/2" prepolarized microphones using the included GRAS GR0010 Adapter for 1/4" preamplifier and 1/2" microphone.
The 26CT has an integrated SMB connector. SMB-to-BNC cables are available, also with angled SMB. The casing is made of stainless steel for maximum strength and durability.
Specifications
| Parameter |
Unit |
Value |
| 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 |
< 50 |
| Output Voltage Swing, min. @ 24–28 V CCP voltage supply |
Vp |
8 |
| 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 |
| Gain |
dB |
-0.45 |
| Power supply (Constant Current Power) |
mA |
2 to 20 (typ. 4) |
| DC bias voltage, typ. |
V |
12 |
| 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 |
| TEDS UDID (IEEE 1451.4) |
– |
I27-0-0-0U |
| Connector type |
– |
SMB |
| CE / RoHS compliant / WEEE registered |
– |
Yes / Yes, Yes |
| Weight |
g / oz |
4.0 / 0.14 |
Conditions: 23 °C Ambient temperature
4 mA / 24 V open loop CCP voltage
18 pF dummy microphone
3 m output coax-cable
GRAS Sound & Vibration reserves the right to change specifications and accessories without notice.
Dimensions
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