HP 339A Info

jurb6006 · 2015-08-01T03:18:57+00:00

One has come in to our realm. We do some high end audio so having something like this desirable. It was bought surplus on the cheap. It is not dead, b ut I am pretty sure it is not working correctly. I've yet to completely lea rn to work the thing actually, and am taking it slow. First off, I DO know the basic tenets of a distortion meter. It filters out the fundamental frequency and measures what remains. Not quite rocket scie nce. Unfamiliar territory for me indeed, but I should be able to understand this. I am looking for failure modes, tips on operation and basic self checks and so forth. I have only gotten so far in the manual but I am on it. The way I see it, these things you take a sine wave, put it through whatever and ca librate the distortion meter somehow. Like set it to full scale, flip the s witch and you get the distortion reading. I cannot get it to act right, at least what I think shoud be right. I have actually confirmed that it does detect distortion. Instead of the onboard o scillator I used my Wavetek 111. Not the greatest but good enough for what I wanted to do. I got the thing to give a useful meter indication and switc hed waveforms. I switched to triangle from sine and the needle didn't go up . OK, now realy I am not sure if the peak/RMS value of a triangle wave is l ess or more than a sine wave. And I fully expected the square wave to peg t he meter, which it did. Until I hit this other waveform on it, looks like _/|_/|_/| and saw the nee dle rise could I be sure this thing is anywhere near being able to really m easure distortion. I don't care what, that half sawtooth with the 50 % dead time will deflect any measuring device less whether it measures average, R MS, peak or smegma. PLUS the thing is only positive going, so the peak valu e is half. And yet the needle moved up. I consider that a good sign. The Wavetek 111 info is available at BAMA if y ou want to really see the waveform. And it is that waveform like, exactly. ...