G.R.A.S. 26CF 1/2'' CCP Preamplifier with BNC Connector, Gain and Filters

Freq range: 2.5 Hz - 200 kHz
Noise: 1.8 µV
Gain: -0.25 / +20 dB
Special feature: 0/20 dB gain, A-weighting and HP filters

Gain and filter switch settings

There are two flush-mounted switches for selecting various combinations of gain and filtering, i.e.:

Gain switch settings:

  • 0 dB - for normal microphone signals.
  • +20 dB - for boosting weak microphone signals.

Filter switch settings:

  • A-Weighting - as required in standard measurements.Linear - to let the microphone signal passunfiltered.
  • High-pass - to cut off unwanted low frequencies.

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 Type 26CF can be used with all G.R.A.S. prepolarized microphones, namely:

  • ½-inch microphones:Types 40AE, 40AD and 40AQ
  • ¼-inch microphones:Types 40BE and 40BD, using the optional½-inch to ¼-inch adaptor RA0019

It has an integrated BNC output connector.

The casing is made of stainless steel for maximumstrength and durability.

1 CCP stands for “Constant Current Power” and describesG.R.A.S. power supplies that maintain a constant level ofcurrent for driving IEPE transducers like this preamplifierwhich can be used with prepolarized microphones such asTypes 40AD, 40AE, 40AO and 40AQ.

Frequency range (±0.2 dB) with 18 pF microphone dummy Hz 2.5 to 200 k
Slew rate V/µs TBD
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 20
Gain dB -0.35
Power supply (Constant Current Power) mA 4 to 20 (typ. 4)
DC bias voltage, typ. V 14
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 - 95
Connector type BNC
CE/RoHS compliant/WEEE registered Yes / Yes, Yes
Weight g / oz 30.0 / 1.06
Conditions: 23 °C Ambient temperature, 4 mA / 24 V open loop CCP voltage, 18 pF dummy microphone & 3 m coax-cable.