How to Measure Tube Amplifier Output Transformer Impedance 

Love the straightforward, no BS simplified approach. Thank you!

thank you! Because of your useful sharing for those who are new to assembling amps like us, wish you good health and look forward to receiving more useful shares from you, dear!

Thanks so much, very helpful and interesting:)

Very good presentation! I agree with you totally that the 1K signal is a good frequency to test OTs. It is a happy medium between the log rhythmic, scale of frequency impedance, vs., the output voltage stability of the signal generator. Hopefully, folks understand your choice in using 1vpp measurement step, to make the turns-ratio math extremely easy to do. :)

You test your output transformers the exact same way I do. Made more sense to me to put a higher frequency tone into it than using 60Hz. I will run my generator to sweep from 20Hz-10Khz just to see how much Db drops with higher frequency. I mainly deal with guitar amp parts so the aren’t none for high fidelity. Nice video. Like the Tek scope. I have an early digital 2430A and a nice old 485. Also have the Rigol DS 1054z which is great for all the readout options it has with a FFT function. Have an old 20Mhz two channel that came with the NRI home study course I did in 1992. I love repairing old test gear too so I have acquired a ridiculous amount of scopes and meters. Not Mr. Carlsons Lab crazy but might if I had the room. I guess I need to start doing repair videos. Used to put up guitar playing videos but the copyright nonsense stopped me 10 years ago. Still have a lot still up but nothing in a long time. Still love playing but really love working on tube gear. Keep up the great work.

thank you thank you . 20:1 turns = 400:1 impedence . it seems like i been looking for this answer for 2 days . i don't fully grasp it yet but im closer .

Fantastic, Thank You!

Thanks for the video!

The way I think about impedance is that it is frequency dependent. That's why the impedance noted on a speaker is a nominal impedance across a range of frequencies.

Hi Skunky 😁 What are your thoughts on silver and where to use it in components for the best results?

Help needed! How do I match impedance of inverter16v AC output SOURCE to 16vAC isolation transformer primary, that I have to hand WIND, for 4 ohms load of 32v AC 6 amps secondary ? Do I use the ohms of primary 16v + 12 amps division or the resistance .06 ohms of inverter output contacts terminals at 20khz frequency? Voltage and turns ratio same as 1:2. The online formula for inductance value of turns requires reactance value in ohms , at the frequency of source.

Have just liked this video because of the presentation of the woman 🥂🥂🥂🥂

most keen

Cute way to explain reflected impedance concept. Another video about damping factor could be "symmetrical".... 🖖

very good clip to help understand more about output transformer. Request how to calculate Load impedance for each tube. For Example why type 45 use 5K OPT? Why 2P29L use 4.6K on 32 ohms Headphone? Thank you in advance.

hi skunky thanks for the video :) now i just have to figure out how to measure my output transformers i have 1 lead tied to the plate of a 6bm8 on the primary and 4 leads on the secondary 2 wire for speaker one ground and a yellow wire going to a 50uf 200v can cap in the power supply section im deconstruting a philips console picked a tricky one to learn off of :)

Thanks great explanation…i just need to buy a signal generator!!

I want 40w output transformer data for El 84 tube amplifier so please help me

What I don't understand is, if the impedance on the load side is reflected to the input side, how can we measure accurately without having matched source and load impedances connected?

Enjoyed your video. I've been dealing with a friend's 1939 Recording King amp, that has an OT with no markings of any kind on it, and trying to determine if its correct for this PP cathode biased amp running two 6L6GC's. He's using an 8 ohm speaker. I'm a bit of a novice, but I have some experience with tube amps. I have determined that this OT has a voltage ratio of 48;1 and thus and Impedence Ratio of about 2300:1. The plate to cathode voltage is 369 VDC, and using a Eurotubes single tube adapter, one tube has a PC of 51.6ma and the other tube is 57.6ma. The cathode resistor is 229 ohms, and its voltage drop is 25.82 VDC. So, if I"m correct, an 8 ohm speaker would result in a reflective impedence value of about 18,400 ohms. I have no idea what the Wattage of this OT is. 18.4K seems awfully high, and I don't know if it's too high for these tubes, or if there is such a thing a being "too high". The tube spec sheet I think shows Effective Load Resistance Plate-to-Plate of 6600 ohms. So that's a big spread. Thoughts? Can an OT harm the tubes or the speaker, or does it just affect the sound? Thanks for your help.

Hi, i'm not good in english, but i need to measure solid state amp. Please make tutorial. Thank's

Just subscribe. Curious to know what is the impedance between 4 to 8 ohm taps, and 2 to 4 ohm, 2 to 8 ohms. I am a physics graduate with life long hobby in hifi electronics, now 67 years old vintage, yet never learned this William Lee Singapore

Impedance takes a while to get your head around. I took a whole semester on it lol

Show your signal gen.

First! :D