The GRAS 26CK ½” Preamplifier, Very Short is a very small preamplifier optimized for use with prepolarized condenser microphones. It is a robust unit that uses a constant current power (CCP) supply. The 26CK 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
- For use in confined spaces
- High-frequency measurements
- High-pressure measurements
- Sound intensity measurements
- Near-field measurements
- Anechoic boxes
- Hearing-aid measurements
Design
The small, ceramic thick-film substrate in the 26CK has a very high input impedance and is shielded by a guard ring, which minimizes the influence of stray capacitance and microphonic interference.
The 26CK 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 the following GRAS prepolarized microphones:
- 40AE ½” Prepolarized Free-Field Microphone
- 40AD ½” Prepolarized Pressure Microphone
- 40AO ½” Prepolarized Pressure Microphone,High Frequency
- 40AQ ½” Prepolarized Random Incidence Microphone
The 26CK has an integrated Microdot output connector.
The casing is made of stainless steel for maximum strength and durability.
Calibration
Before leaving the factory, GRAS products are tested and calibrated by GRAS, and an individual test certificate is included with the product.
GRAS Sound & Vibration continually strives to improve the quality of our products for our customers; therefore, the specifications and accessories are subject to change.
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 |
| High-pass filter @3dB cut-off |
Hz |
TBD |
| 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 |
– |
Microdot 10/32 |
| CE / RoHS compliant / WEEE registered |
– |
Yes / Yes, Yes |
| Weight |
g / oz |
TBD |
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.
