[Test-Equipment] Using an HP 331A Distortion Meter

[Barry]

I'm a bit new to using a distortion meter and have a basic question.  When connecting the device I want to test to the meter's input, I assume it is necessary to terminate the generator properly (e.g. into a 600-ohm resistor, etc.) and that's so that the generator sees the proper load.

What's confusing me a bit about this I may use this to measure distortion for a 600-ohm-terminated signal as well as connecting it to the 8-ohm load for the PA output.

Does the meter not really care what impedance it sees on the input?  It just seems odd that I would feed it a 600-ohm load in one case and an 8-ohm load in another.

Sorry if the question doesn't make a whole lot of sense but I'm confused a bit as to whether additional matching is necessary to get an accurate reading (or, at least, as accurate as an older analog device like this can give me).

Thanks,
Barry - N4BUQ