Is it really necessary to match the impedance of the electrodes to the TDT headstage?
It is true that the impedance of the electrode should always be much less than the impedance of the headstage in order to have a good signal-to-noise ratio (SNR). However, the TDT low and high impedance headstages both have very high input impedances that are set specifically to record a high SNR only with an electrode whose impedance is in the specified range for that particular headstage. See the technical specifications page for your headstage to find out the acceptable impedance range.
