DAM50 Extracellular Amplifier

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A family of very low noise battery-operated amplifiers

  • Battery powered to eliminate line noise
  • High pass and low pass filtering
  • Single ended or differential operation
  • DC/AC amplification
  • Variable output positioning
  • Constructed of high quality components to ensure minimal intrinsic (shot) noise
  • Portable
  • Rack mountable
  • The DAM50 package now includes the 300647 shielded metal electrode cable and one shielded modular cable.


See the current Spec Sheet.

See what you need to know before you buy an amplifier.


  • Very low internal noise
  • Ultra quiet DC power supply ­— no AC required
  • Intrinsic low susceptibility to ground loops
  • Small footprint
  • Cost-effective
  • Electrostatic Discharge Protection!


  • Amplifying biopotentials from metal electrodes
  • Brain slice field stimulation
  • EAG (Electroantennogram)
  • ERG (Electroretinogram)

WPI’s DAM series amplifier’s are well known as a standard of the industry for extracellular potential amplification. These battery powered bio-amplifiers are designed with a compact chassis profile that enables you locate the unit closer to the preparation and thereby minimize long lead lengths which contribute to noise. Each amplifier is equipped with selectable high and low filters, and a position control to offset galvanic potentials which may develop during recording.

DAM series amplifiers can be used as stand-alone units on any tabletop or use optional clamp-mounting hardware to locate them conveniently within the work area. Alternatively, a pair of amplifiers can be mounted into a standard equipment rack with a rack mount kit (3484). A variety of hook up accessories are available to configure your application.

Reducing Noise with Differential Amplification

Differential amplification is of great importance in bioelectric recording to reduce the ever present effect of noise interference from power line induction. A well designed differential amplifier will significantly diminish power line (mains) noise. It is most essential that the preparation be connected with an electrode to a good electrical ground as well as to the grounding wire of the DAM50 itself. This should have the effect of greatly reducing electrostatically induced potential. In addition to the preparation ground, two differential input connections must be made via appropriate electrodes applied to the recording site so as to optimally record a bioelectric potential difference.

Feature Comparison Chart

  DAM50 DAM80
Input Mode AC/DC AC
Input Configuration Differential/Single Ended Differential
Gain Range 100-10,000 (AC)
10-1,000 (DC)
100 - 10,000 (AC)
High/Low Filters Yes Yes
Offset Position Control Yes Yes
Current Generator No Yes
Remote Active Headstage No Yes
Output Connection BNC 3.5 mm mini phone
Standard Input Connection unterminated wire Mini banana
Power Supply (2) 9V alkaline batteries (2) 9V alkaline batteries

DAM50      Dam50

INPUT IMPEDANCE 1012 Ω, common mode and differential
GAIN AC: 100x, 1000x, 10000x, DC: 10x, 100x, 1000x (DAM50)
AC MODE NOISE 0.4 μV RMS (2uV p-p) 0.1-100 Hz
AC MODE NOISE 2.6 μV RMS (10uV p-p) 1 Hz-10 kH
DC MODE NOISE (DAM50) (DAM50) 7.5uV RMS (30uV p-p) 3-10 kHz
BANDWIDTH FILTER SETTINGS:AC Mode Low frequency, 0.1, 1, 10, 300 Hz
BANDWIDTH FILTER SETTINGS: DC Mode(DAM50) High frequency, 0.1, 1, 3, 10 kHz
BATTERY TEST Audible tone
CALIBRATOR SIGNAL 10 Hz square wave
POSITION Approximately 250 mV
EXTERNAL COMMAND Input Voltage ±10 V commands
AC or DC current waveform ±50μA max. amplitude @ 200 KΩ
BATTERIES 2 x 9 V alkaline (included)
DIMENSIONS:DAM50 8 x 4 x 1.75 in. (20.3 x 10.2 x 4.4 cm)
SHIPPING WEIGHT 3.5 lb. (1.6 kg)

The following bandwidth charts for the DAM50 show the response of the amplifier when various filters and gains are used. For larger images, click on the thumbnails below. 

Bandwidth charts for the DAM50

GAINS: This chart shows the standard 3dB frequency cutoff at  maximum filter band pass.

The standard 3dB frequency

FILTERS: Various low pass and high pass filters were applied at the AC x1000 gain setting to show the bandwidth of and actual DAM50 amplifier.

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More Choices:
  1. Electrode Cable Assy Dam 50
    Electrode Cable Assy Dam 50
  2. Ringstand Mounting Kit
    Ringstand Mounting Kit
  3. Uninsulated Mini Banana Plug
    Uninsulated Mini Banana Plug
  4. Rechargeable 9V Battery
    Rechargeable 9V Battery
  5. BNC-TO-BNC CABLE, 6 '
  6. 9V Battery
    9V Battery
  7. Adapter Cable
    Adapter Cable
  8. Red Insulated Mini Banana Plug
    Red Insulated Mini Banana Plug
  9. Adapter Electrode 0.031 for DAM80P
    Adapter Electrode 0.031 for DAM80P
  10. Optional Probe for DAM50
    Optional Probe for DAM50
  11. Electrode adapter for DAM probes
    Electrode adapter for DAM probes
  12. Black Insulated Mini Banana Plug
    Black Insulated Mini Banana Plug
  13. DAM Series, PM Series
    DAM Series, PM Series
  14. Ag/AgCl Electrode
    Ag/AgCl Electrode
    Multiple SKUs
  15. Tungsten Profile C, 127 mm long
    Tungsten Profile C, 127 mm long
    Multiple SKUs
  16. Manual Micromanipulator
    Manual Micromanipulator
    Multiple SKUs

Differential Applications for Metal Electrodes

The images below show two applications for metal electrodes. Click on the images to see a larger view. 

In this first example, a sealed RC1T Ag/AgCl electrode pellet is wired to the amplifier cable. This also shows a differential configuration.

dam50 setup 1

This second example shows an EP2 silver/silver chloride electrode pellet connected to  the amplifier adaptor 5389. This shows a differential configuration. The EP2 is suitable for use in a mouse cranial application. To do so, it needs an extension wire 3294 to connect it to the 5389 adaptor.

dam50 setup 2 

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