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

[Dale H. Cook]

At 04:13 PM 9/2/2014, David DiGiacomo wrote:

>The distortion analyzer has a high impedance input, so it doesn't care what the source impedance is, as long as it's not too high.

David is correct. The input impedance of the 331A / 332A / 333A / 334A is 1 megOhm, shunted by 70 picoFarads or less depending upon mode. As he pointed out, you do need to terminate the source properly. I keep a variety of loads with my 334A, although I most often don't need them because I most often am using the RF detector port on the back (also found on the 332A) to proof small AM broadcast transmitters in the shop.

Dale H. Cook, GR / HP Collector, Roanoke/Lynchburg, VA
http://plymouthcolony.net/starcity/radios/index.html