Differential Amplifier (DP-304A)

Differential Amplifier (DP-304A)

The DP-304A is a four channel AC/DC differential amplifier highly suited for EEG, EKG and extracellular recording.

  • High input impedance
  • High common mode rejection: 120 dB at 60 Hz
  • Low noise with high gain
  • High tolerance to DC baselines

Item# Description U.S. List Price Quantity
64-2360 Differential Amplifier, four channel, with IC-2S cables
64-2361 Differential Amplifier, four channel, with IC-4M cables
64-0046 IC-2S Replacement Input Cable Set, qty. of 2
64-0047 IC-4M Replacement Input Cable Set, qty. of 2
460-7013 (BNC-6) BNC to BNC cable, 6 feet (Pomona)
460-7032 (BNC-2) BNC to BNC cable, 2 feet (Pomona)
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Summary of Features

  • Four channel AC/DC pre-amplifier designed for amplifying weak signals such as EEG, EKG and extracellular action potentials. Inputs switched ON or OFF individually.
  • Powered by 110 to 130 VAC at 60 Hz or 220 to 240 VAC at 50Hz with 10 V/A
  • Very low noise with 8 microvolts peak-to-peak (1-Hz to 10-kHz with input shorted)
  • High gain with selections of x10, x100, x1000 and x10,000
  • Excellent common mode rejection of 120 dB min (100,000:1) at 60 Hz with input resistance 1012 ohm typical.
  • Both high pass and low pass filters, each with multiple switch settings.
    • Low Frequency (high pass) Filter Settings: 0.1, 1.0, 10 & 300 Hz
    • High Frequency (low pass) Filter Settings: 0.1, 0.3, 1.0, 3.0, 10 & 50 kHz
  • DC offset of ± 600 millivolt at output BNC operates in both AC or DC modes.
  • A front panel test push button applies 1mV pulse to the amplifier input to check intermediate gains and support equipment.


High Input Z, High CMR

High common mode rejection is very important in minimizing electrical interference. The high input resistance of the DP-304A (1012 ohm typical) ensures that the instrument's high CMR will not be degraded by differences in source impedance at the input. This is important in extracellular recording, where the difference in resistance of the recording and indifferent electrode is often large.

High DC Tolerance

Extracellular action potentials are typically measured in microvolts but are usually accompanied by much larger DC electrode voltages. The DP-304A is designed to amplify these microvolt level events with as much as ± 2 VDC at the input.

High Gain, Low Noise and Bandwidth Limiting

With gain selections at x10, x100, x1000 and x10,000, even microvolt signals are sufficiently amplified for computer and recorder inputs. Noise is very low, typically 8 µV p-p at 1 Hz to 10 kHz bandwidth. Reducing the bandwidth with the low pass and high pass filters further lowers noise.

Calibration Signal

The internal Cal signal provides a convenient check of amplifier gain and operation.

Rack Mountable

The DP-304A is shipped with rack mount hardware and is line powered.

IC-2S Cable IC-4M Cable

Input Cables

The DP-304A includes IC-2S input cables (2 per channel) which are not terminated at the outboard end.

The DP-304AIC includes IC-4M input cables (2 per channel) having a 2 mm pin and alligator clip at the outboard end.

Voltage Gain, AC/DC x10, x100, x1,000, x10,000
Input Resistance 1012Ω typical
Leakage Current 1.0 pA typical
Common Mode Rejection 120 dB min (100,000:1) at 60 Hz
Noise, input shorted 8 µV p-p, 1 Hz to 10 kHz
Low Frequency Filter Settings (high pass) 0.1, 1.0, 10, 300 Hz
High Frequency Filter Settings (low pass) 0.1, 0.3, 1.0, 3.0, 10, 50 kHz
Offset Control Range ±600 mV min at output, any gain setting
Calibration Signal 1 mV p-p at 10 Hz
Max. Common Mode Signal ±2 V
Output Voltage Swing ±10 V, ±5 V at x10 gain
Output Resistance 50 Ω
Input and Output Connectors BNC
Power Requirements 92 - 250 VAC, 50/60 Hz, 20 VA
Physical Size 9.0 x 42.5 x 19.0 cm
(H x W x D)
Shipping Weight 4.55 kg
Warranty One year on electrical components
DP-304A Manual (092915).pdfdescription