This is a great Reverse engineering and analyzing video.

PS. For anyone not understanding the square wave discussion, a square wave is ideal for measuring the response of an amplifier. The square wave is made up of all the odd harmonics of the fundamental - up to infinity. It can therefore show frequency and phase response by it's variation from the ideal. The rising trace (rise time) can be simply thought to represent it's high frequency performance, if it was curtailed the rising trace would curve over the time domain. The flat portion represents low frequency response, and a falling/drooping trace would show poor bass response. Google will have pictures of square waves showing these in detail. This was an excellent transformer performance - What did that little blip at the top of the rising trace mean? Was it bass or high frequency related, or both?

Great video; very educational. I followed all 3 videos, and they all are very interesting. Thanks a lot

Excellent video Mark, very informative - thank you!

Thank you. Much-needed

great video! have you made a video showing line level balanced to unbalanced arrangements?

Brilliant stuff! Nothing left out, so thanks for the education. Colleges charge big money for lecturers not as good as you.

Nice video big thumbs up mate

Thank you. I have collected a lot of these transformers over the years. Sadly, At age 70 most will go unused. My interest is with microphone preamps and not SUT. The principals are the same. How do I come up with the mic loading instead of the cartridge loading.

PS The Dynavector 10X nee Ultimo 10X is designed to playback into a standard MM stage. Using a 17x transformer (argghhh @30x) would overload most stages heavily, add distortion and add an extra stage of unnecessary gain with incumbent errors. I know what you said about matching and getting good sound when not expecting it, but this is expecting too much. This would be ideal for the Denon though, and anyone wanting a great cheap moving coil, the studio stalwart 103 is one of the greats for peanut money. A good transformer will knock spots off most of the awful MC stages found in modern amps.

Hi, and thanks for the video, very informative. You indicated the transformer came from an old tape recorder? I have had a number of tape recorders any have not seen any SUTs on them, what kind of old tape recorders have these, well except for an Ampex!

Mark, would you be willing to share where you purchased your white/color striped wire from? I'm restoring an early 1960's oscilloscope that has some mouse damage to the wiring. I'd like to replace the damaged wiring with the same color code if possible. Thank you - Dave

Isn't there a danger of magnetising the core when measuring DC resistance? I thought DC through small tfmr's was to be avoided.

So did you use the square wave (because it's made up of the fundamental and odd/even harmonics) to substitute for the audio spectrum sweep, to determine flatness of response?

PART THREE 😭

You should really NOT be using those ground clip leads on your scope probes for impedance and frequency response measurements. Not a "big" issue at such low frequencies, but with high impedances it can become a consideration.

This might be the company. Can you e-mail them for specifications? www.triadmagnetics.com/index.html

It makes absolutely no sense to test all connections from the first coil to a secondary coil because you've already got 10-20 Ohm resistance. You must see at least this value in case of some shortage. And if someone has a two beams oscilloscope, he is not a total noob who needs an explanation of what is an opposite phase of a signal. 'cmon..