HP 334A Distortion Analyzer

Workshop Project #16 - HP 334A Distortion Analyzer This time, I have another - almost - vintage test equipment on my bench. I was looking for a distortion meter to check up on my occasional amplifier projects. Not that I personally care much about anything "beyond my hearing capabilities", but it's always nice to compare values between devices, particular between left/right channels of stereo amplifiers, where slight deviations might be noticable after all... While browsing e-bay for something useful of that type, I discovered this HP 334A model. It was an affordable "as is" or "the light turns on" offer, and the service manual was readily available on the internet. MINE! Join me in my fight against set screws, broken light bulbs, aged capacitors and empty camera batteries to find out if this device will serve me in future projects! ADDENDUM: By now, I did read up a bit more on the definitions, and it seems that the device measures "THD+N" - it essentially puts a sharp notch filter in the fundamental frequency, that you can tune with the bridge, and the remianing signal (harmonics and noise) is what shows up on the meter. ADDENDUM 2: Thanks to mikant71 for pointing out that a slight mistake made its way into the explanation process: During the distortion measurement, after adjusting the level, the sensitivity should not be changed; rather the meter range is the one that needs to be bumped to find the minimum value. My bad, that must have slipped by in editing several example shots together. 0:00 Intro / Presentation / Disassembly Problem 3:35 Cleaning 4:43 Meter Movement 6:35 Replacement Switch Handle 7:10 Case Information / Mains Switch 8:50 Sliding Switches 10:20 Potentiometers 11:25 Banana Plugs 12:42 Frequency Dial Assembly / Sliding Switch 14:35 Neon Indicator / Potentiometer mounting 15:25 A Tale of Two Grounds 16:26 Recapping 17:20 Black Box - LDR Setup 19:45 Front and Back Panel Mounting 21:23 Power Supply Test / Wiring Components / Knobs 23:35 Power On! / Calibration 24:35 Voltmeter Demo 25:15 Distortion Measurement Demo 26:24 Summary, Outtake Music: My Train's A Comin' Unicorn Heads (YouTube Audio Library) You can support me on Ko-Fi: https://ko-fi.com/atkelar Thanks to Rik I have a nice replacement switch handle; visit his blog at http://justanotherelectronicsblog.com Read up on the definition of THD on Wikipedia https://en.wikipedia.org/wiki/Total_h...