Related Manuals for G.R.A.S. 14AA
Summary of Contents for G.R.A.S. 14AA
- Page 1 Instruction Manual G.R.A.S. 14AA Electrostatic Actuator Amplifier www.gras.dk LI0010 – 1 October 2015...
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Page 2: Revision History
Revision History Any feedback or questions about this document are welcome at gras@gras.dk. Revision Date Description 23 May 2007 First publication 4 November 2013 Updated connection diagrams and specifications 30 January 2014 AC output specified as V RMS. 1 October 2015 Correction to Fig 2. -
Page 3: Table Of Contents
Contents Introduction .................. 4 Setting the Mains Voltage ............... 6 Driving a Microphone as Sound Source ..........7 Electrostatic Calibration of Microphones ..........8 Technical Specifications ..............9 The AC Outputs for Microphones and Electrostatic Actuator ......9 Other Specifications ................. 12 Accessories ................ -
Page 4: Introduction
The input signal to the 14AA is supplied via a standard BNC connector and can be any signal up to 1V RMS. The input signal is amplified 40 dB (100 times) in the 14AA for a maximum output signal of 100 V RMS. - Page 5 Fig. 2. 14AA principle. The 14AA electrostatic actuator amplifier consists of a 40 dB gain, high voltage amplifier and two high voltage DC power supplies as shown in figure 2. The input signal from the BNC connector on the front panel goes to the amplifier stage. The input signal must be limited to maximum 1 V RMS in order not to overload the amplifier.
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Page 6: Setting The Mains Voltage
Setting the Mains Voltage Before conecting the 14AA to the mains power the voltage setting on the rear panel of the 14AA should be set to the correct local mains power voltage. The voltage setting is indicated in the Voltage setting indicator on the rear panel, see figure 3. To change the setting, remove the fuse holder by inserting a small screwdriver in both sides of the fuse holder as indicated in figure 4. -
Page 7: Driving A Microphone As Sound Source
IEC 60318, the sensitivity of the transmitter microphone can be assumed to be identical to its response as a receiver. A signal generator is connected to the input BNC connector of the 14AA and the output is con- nected to a transmitter adapter. -
Page 8: Electrostatic Calibration Of Microphones
• 1⁄2”, 1⁄4” and 1/8” microphones: G.R.A.S. RA0014 1/2’’ Electrostatic Actuator for frequency response calibration. (Adapters for 1/4” and 1/8’’ microphones are included with the actuator). Fig. 9 shows a block diagram showing a setup using the 14AA for frequency calibration with an electrostatic actuator. Electrostatic Actuator... -
Page 9: Technical Specifications
The AC Outputs for Microphones and Electrostatic Actuator Under open loop conditions, the AC outputs of the 14AA are linear to over 200 kHz. However, the cable connected to the output limits the high-frequency performance in the same way as a low-pass filter. - Page 10 Typical Frequency Response for the AC Outputs, 0 VDC and + 200 VDC RG58 Cable, 1 Meter 100V 1000 10000 100000 1000000 -0,1 -0,2 -0,3 Frequency [Hz] Fig. 13. The Frequency response for the 0 VDC and 200 VDC outputs, 1 meter RG58 cable, 10, 30 and 100 V RMS. RG58 Cable, 3 Meters 1000 10000...
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Page 11: Other Specifications
The AC Output +800 VDC (for electrostatic actuator) Output Signal 100 V RMS –3 dB Low Frequency Cut-off Open loop 1.6 Hz 1 MΩ load 17.5 Hz Max. Frequency at 100 V RMS output with RA0014 ½" 200 kHz with RA0015 1” 50 kHz Max Output Current 2.5 mA AC... -
Page 12: Calibration, Warranty And Service
Warranty All G.R.A.S. products are made of high-quality materials that will ensure life-long stability and robustness. The 14AA is delivered with a 2-year warranty. Damaged diaphragms in microphones can be replaced. The warranty does not cover products that are damaged due to negligent use, an incorrect power supply, or an incorrect connection to the equipment.