HP334A Distortion Analyzer

[ssbothwell KJ6RSG]

hi guys,

i found an HP334A for pretty cheap and was wondering how useful it would be for designing and using HF equipment. the 334a has a built in envelope detector for checking distortion of a modulated signal. i was thinking it would be a nice tool for checking the linearity (is that a word?) of amplifier stages i am working on. does that make sense and is there anything else i can use it for?

[Opcom]

If I'm not mistaken that's one of the models that the audio folks like, Can't go wrong there - use it to work on your speech amp and any hi-fi gear you might build or repair.

[KJ4OLL]

Hi,
I use mine for fine-tuning the signal-to-noise after aligning my R-390A.
(As per Chuck Ripple's R-390A training video)

[Tom WA3KLR]

Another piece of HP gear that does have very high linearity demodulation is the HP8901A Modulation Analyzer, 7" rack mount.  It was designed to check AM and FM transmittter's modulation and incidental AM and FM.  I have piped the demodulated output to my audio distortion analyzer as I recall.  I sometimes add my Bird 1000 Watt 30 db attenuator ahead of the input, punch in the attenuator's factor (say 1017) and get a nice digital watts read-out.

[John K5PRO]

You will need to have a good source (audio oscillator) to drive the equipment that your 334A will analyze. If the source has poor sinewave quality, such as from a general purpose function generator, then the THD readings of the 334 will quantify that. The Hp339A had the low distortion source in it, as do Sound Technology, Tektronix and Audio Precision audio analyzers. The 334A is excellent in that the RF detector is built in, up to 65 MHz range, which was nice for Proof Of Performance measurements of broadcast transmitters. Have fun!

[WD5JKO]

You will need to have a good source (audio oscillator) to drive the equipment that your 334A will analyze. If the source has poor sinewave quality, such as from a general purpose function generator, then the THD readings of the 334 will quantify that.

    If your computer has a decent sound card, then a software based audio generator can make a very low distortion audio source, and have all kinds of bells and whistles.

  I use the Dr. Jordan software:

http://www.dr-jordan-design.de/index.htm

  They have a free downloadable neat audio generator with some of the DSP features disabled. Here is the link to download the file directly:

http://www.dr-jordan-design.de/Download/SigGen.zip

  You can run two of these at the same time for two tone testing. Running into a laptop speaker, can surely irritate family members, and the house cat too. 

Regards,
Jim
WD5JKO