Medusa preampli
fi
er's 25-pin connector. The simple interface to the RA16PA preampli
fi
er
makes it easy to connect your electrodes to our system.
An adapter is also available to connect a low impedance headstage to a PZ preampli
fi
er. See
for more information. A built-in impedance checker can be used to test
each channel and the reference. Additional 20x gain on the headstage improves signal-to-noise
of low voltage signals.
Impedance Checking with the Low-Impedance Headstage
The impedance checker on the RA16LI provides a simple check of the channel impedance
relative to ground. To check the impedance level, press the button next to the channel
indicator. The highest-level light indicates the maximum impedance between the channel and
the ground. If all impedance lights are illuminated it is likely that one of the channels is not
properly connected. The (-) impedance button checks the impedance between the reference
and the ground.
Headstage Voltage Range
When using a TDT preampli
fi
er the voltage input range of the preampli
fi
er (PZ5, Subject
Interface, RA16PA) is typically lower than the headstage and must be considered the effective
range of the system. Also keep in mind that the output range of the headstage varies
depending on the power supply provided by the preampli
fi
er. PZ5 and Subject Interface supply
± 2.5 V. PZ2 and RA16PA preampli
fi
ers supply ± 1.5V. Third party preampli
fi
ers may vary. TDT
recommends using preampli
fi
ers which deliver ± 2.5 V or less. The table below lists the input
voltage ranges for the RA16LI headstage for either ± 1.5 V or ± 2.5 V power sources.
Power Source
Headstage Input Range
± 1.5 V
± 33 mV
± 2.5 V
± 80 mV
Low Impedance Headstages | 6
