Measuring Output Transformer Primary Z with the FNIRSI LC1020E LCR Meter

For years I had been measuring output transformer primary impedance using an arduous old-school procedure similar to Uncle Doug's and Skunkie Design Electronic's videos. Recently, this video from Mr. Carlson's Lab popped up in my YouTube feed - a significantly simpler process!

Although I had a gut feeling it wouldn't work, I just had to try the same experiment using my very basic Proster LCR meter. No go, just a DCR reading. 😔 

So I went to shop for the best price for a FNIRSI LC1020E LCR meter used by Mr. Carlson...😊

With the recent adjustment of tariffs, I logged in to my AliExpress account after more than a year's hiatus. The LC1020E was $30 cheaper there than if I ordered through Amazon. $52.27 was my landed cost inclusive of state sales tax. Within 7 days, the package arrived at my doorstep.

What's in the box?

Aside from the LCR meter itself, there's a pair of standard test leads, a user's manual, a shorting bar for calibration, a USB-A to USB-C cable for charging + a Kelvin Clip. A Kelvin clip has two leads in each probe and supposedly more accurate for very low impedance measurements.

Let's measure a couple of output transformers

Using my old method, I measured an 8kΩ primary Z from the EICO ST40 PP OPT. The 8kΩ figure matches the results taken by the LC1020E after I took the average between the four frequencies within the audio bandwidth.

Even if I've only scraped the surface of the FNIRSI LC1020E LCR meter's capabilities and have yet to delve further into its capacitance, inductance and resistance features, this tester is already a welcome addition to my audio test bench.

Thank you Mr. Carlson's Lab!🍻