Seismic Amplifier/Filter Board

Last Updated: 3/02/21

Note: This board is no longer in production 

Here is the schematic and artwork in Gerber format to build this board. This files are also available on GitHub here

Online Documentation


Number of channels:        1, 2 or 3 Channels
Gain:                      ~170 to ~6,000 - Set by Trim Pot and Jumper
Frequency Response:        0.02Hz (50 Sec.) to 10Hz for Lehman Type Sensors or
                           0.05Hz (20 Sec.) to 20Hz for Geophone Sensors  (Note 1)
Lowpass Filter Type:       8 Pole Butterworth Filter
Highpass Filter Type:      1 Pole Butterworth Filter
Input Connectors:          RCA jacks (Stereo Equipment Type) or
                           .156 Inch 2-Pin Molex Connector or
                           Terminal Screw Block
Input Impedance:           ~10K  (Note 2)
Output:                    +- 10 volts into a 600 ohm load 
Power Requirements:        16 to 28 VDC or 12 to 18 VAC ~150MA Power Supply
Power Connector:           2.1mm X 5.5mm Male Jack on the Board
Board Dimensions:          7.750 x 5.750 Inches or 19.655 x 14.605 Centimeters


Each channel has a very low noise front end op-amp, a 10Hz or 20 Hz (Note 1) 8 pole lowpass filter, 50 or 20  second 1 pole highpass filter, and an output op-amp that can drive up to 100 feet of coax cable and a 600 ohm load. 

Frequency Response Plot:

The plot below shows the frequency response of the PSN-ADC-EQAMP with the standard Lehman and Geophone lowpass and highpass filter configurations.

Power Supply Requirements:

Input / Output Connectors:

The input and output connector for each channel can be one of the following. Please specify when ordering. 

If the board is placed in the option plastic box you will need to use either the .156 Molex or terminal block screw input connector option. There is not enough room in the box to use the RCA jack and mating plug.


Additional Information:

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Larry Cochrane -