Oscilloscope: DC & AC, Signal Tracing in Amp Circuit, RMS Output Measurement 

As a former math teacher, I'm embarrassed to admit that there is an error in my formula for the calculation of RMS power. The peak voltage should be corrected to RMS (i.e. multiplied by .707) prior to being squared and divided by the speaker impedance......not after :(

This is the best oscilloscope tutorial I’ve ever seen. Took me way beyond what I learned (and taught) in Community College.

Knowledgeable men such as yourself who are willing to take the time to share are rare, and absolutely beyond value to the rest of us . Thanks again sir. You will always have a willing and eager audience.

Uncle Doug is the teacher that we wish we had in school. Thank you Uncle Doug!

I alredy know how to operate an oscilloscope, but I still watch these videos just because I love how you teach

Well Doug , I’m a 53 year old electrician who never got into electronics until watching your videos. When this covid thing broke out, I decided it was time for a new hobby. So I bought a bench scope, bench meter, a new solder station, a couple of power supplies, variac and a sig-gen. I’ve been watching your vids pretty religiously and you have taught me so much already. I really have to thank you sir. I doubt you’d ever need it but if you ever have mains or premise wiring issues, I’m all ears!

Always appreciative of your shared knowledge. Didn't see Jack's new friend on this video. Miss Rusty very much. RIP

Now I know why so many others rave about YOUR videos. Thank you!

I love Uncle Doug and his videos. Every time I was thinking "but what about..." he answers in the video. God bless Uncle Doug.

Thank you, thank you thank you for all the practical instructional videos!

Fascinating stuff as always. Greetings to Uncle and Jack. You get me back into this every winter.

Thank you very much uncle Doug. This educational series are awesome.

Thanks for another terrific video, Uncle Doug

Fantastic demo. With the adding I understand now how amplification is possible.

Thanks Uncle Doug, you are a great teacher!

Re: AC and DC co-existing within the same conductor. I tied my brain into knots trying to follow and interpret tube amp schematics before I caught onto this principle. Finding that simple key removed the "magic" and suddenly there was light. :)) Years later, I think I still have marks from all the head scratching.

I have a nice older tektronix 453 but no practical experience. Thanks for a very clear explanation amd demonstration of the basics I needed to see.

Thanks Doug , This is definitely THE best scope tutorial i have ever seen .

Amazing amount of information available in one video.

Amazing tutorial. Amazing teacher.

Doug, this video is very much appreciated. It clearly explains what I thought I knew already. Thank you so much..

Simply wonderful explanation, thanks.

Fantastic instructions with clear and precise information. I really enjoyed this. Thank you for your lessons.

When I came across your channel a few years ago I thought this guy must have been a teacher. Your pedagogical skill comes through. With you I simply get it. Glad you’re out there.

Uncle Doug+ Very professional. I love the fact you go into detail for the beginners. Most would overlook most of what you do, thank you! This is a real seminar, not the average RU-vid video.

Uncle Doug is a friggin genius !!! I just can't get enough ! These videos are off the hook ! SUPER WOW and many thanx!!!

Awesome stuff as always! Yes please more videos about uses and trouble shooting on amps like this! I just scored a similar analog oscilloscope to my tool kit, yay!

Excellent! Learned a TON! Thank you

Thank you for that very detailed explanation and demonstration.

Yes!!!! That was great. Thank you for doing it! More scope vids please!!!

Brilliant! So informative

I like old style cro. I have also the same tech.I also love the frequency generator.You made a perfect combination of the limiter and the isolation transformer.I have enjoyed it and learned something usefull.

Thanks Doug,,, once again excellent video on this subject.

Great video. Learned a lot. Thanks for sharing.

Thank you Doug! Thanks to your videos I was able to get an old Leader 3100a I bought off ebay up and running. Love your cat...beautiful kitty!

Another great video. Thanks for sharing this with us.

Awsome video, again clearly explained, thankyou for sharing

Fabulously instructive video. RU-vid exposes these to me in mysterious order, but I'm glad I finally got to this one! Thank you so much

I LOVE your kitties ! Puts a smile on my face when you feature them in your videos. I have a cat myself, his name is Thunder.

These have been incredibly helpful thank you!

another great one! thanks UD!!

Great video, thanks for sharing!

I learned something new today. Thanks!

I thoroughly enjoyed this video! It was just what I needed! I have a couple of scopes but my use of them is very basic. Many thanks to Uncle Doug and to the generous subscriber who donated the amplifier utilized in the making of this video. Using an oscilloscope and tracing a signal for grounding errors and failed components are what I need to see the most. I'm glad to have found this channel and this video - thank you very much Uncle Doug! I've subbed your channel and will become a Patron very soon! All the best - Luther

as always great info for old timers and new tube guys , thank you sir

Great video again looking forward to the amp restore and some more of your guitar playing

Best to teacher ever ,master Doug...

Doug, you have an absolute fantastic bed side manner as we say in the UK. !

I never post a comment all this years, I follow you since the beginning and see all yours videos. Your a true Maestro. i just want to say one thing and i just want to Thank you for all I have learned from you Oncle Doug. Thank You.

Outstanding videos. Can't compliment you enough :) You are a legend Doug. All the very best from Ayrshire, Scotland :)

I always used my tongue to test the 9V's. Thanks Uncle Doug for most the enjoyable educational episodes ever caught on video they are Gold. I do appreciate them & you I always learn something. Excellent teaching.

your detail in explaining and using it with therory calculations is very informative ,I learned alot about the ossiloscope and how to adjust it for signal tracing ,thank you so much Doug your a Great teacher!!!

Thanks Uncle Doug! This series has really helped me to utilise my Tektronix TAS 465 in a safer and more useful way. I was unaware of the potential hazards without the use of an isolation transformer, which will be my next purchase. In my opinion, your videos are the most clear & succinct explanations on these interesting topics available on the net. Looking forward to future episodes! Patreoned!

VERY informative video Uncle Doug. since I got my cheap scope on Amazon, I've been signal tracing my amps, and having loads of fun!

Great video and information!

Thank you very much for this video, so well explained. I'll definitely wait for your forthcoming videos. Regards!

Hi, thanks for the video, very helpful, from UK.

Once again, thank you for the clear/informative video's. For Christmas i'm getting a Siglent 4 channel 100 Mhz scope and I just won bids at work (Zoll Medical - Leader sig gen, Fluke DMM and a 10A/20V power supply) so, I'll have a fairly well rounded home lab bench in a few weeks. Having successfully build and gig with 2 tube amps, it will be nice to finally "see" more deeply into what is going on in each gain/transformer stage of subsequent builds, mods, and some day designs. Thank you!

Doug. I wish you had been my electronics lecturer! There were so many things that I didn't understand that It took me years to realise. This is probably, no definitely, the best simple introduction to a scope. Again it took me years to work most of this out.

Thanks uncle Doug I like the way you explained it it makes so much sense and it's very fascinating ... I have a basic understanding of electronics and I completely followed what you said and learned a lot thank you

Good information there, thanks for sharing!

Thank you so much, great lesson

As allways another helpfully vid doug thank you

thanks man so much for your time and valuable info really much appreciated

Superb Uncle Doug. Thank you. I still miss Rusty.

Well that was a lot of fun from a simple circuit in very capable hands :) Everybody makes mistakes, the important part is to notice and gracefully correct them; making you, sir, a gentleman and a scholar.

You're the best Uncle Doug

Excellent video.....I bought a Sencore SC61 Oscilloscope and a Tenma 72-455A Signal generator like yours and followed everything you said on this video...I'm soon going to be one of your patrons cause I love your videos and the way you teach....I also like Mr Carlson's Lab videos but there soooo long and a lot of stuff he says goes over my head.

OUTSTANDING, you range of topics is just awesome. I had a scope and signal generator and sold them because i had no idea how to use them properly. Had i seen this video i would certainly keep them to check these homemade Amps. I had not idea how much fun amps can be. Well I will keep looking for bargains. maybe i can get another set of gear. This was great no part 2, Thank You Doug . You may not appreciate that your videos even older ones are helping a whole of folks figure stuff out. I expect even after we are all gone these video will be watched and education even more people. What a great act to do for education. D

Great video.

Uncle Doug,how did I ended up here? I was trying to understand how AC is measured by 10x probes. Usually I'm here for amps, this is a bonus info video.

Jack is so cool!

Thank you for another great lesson uncle Doug. I will have a look if you made more of these scope videos. Never used one but I'm at the point I should. It would be great to see how to find problems in tube amps with it. Jack is an awesome cat, great to see him in your videos. I would sure hire him for amp sniff tests

Love it uncle doug!. 🤙🐱

Greetings uncle D! Signal tracing has always been my favorite topic of your videos. Its always good to revisit your award -winning videos. They also offer hi level entertainment and make this subject fun and rewarding when we apply your techniques and solve problems. I want to thank you again.

Learning one step at a time

informações importante obrigado um abraço Sul do Brasil

Love your videos and of course Jack🐱😁

Thanks every so much for this - I've heard people say you can blow yourself up with oscilloscpes on amps but the same people will tell all sorts of old wives tales about valve amps! Thanks for explaining the sea of controls, fairly simple really. Much obliged Doug!

I used to hate Thursdays, but it's rapidly becoming the best day of the week.

Thank you, Uncle Doug. I needed this to trace the signal in my Princeton Clone. Now I know how to do it. You are a good teacher. Jim

That was a good one. When you overlay the output and input from V1 you can see the amplification and signal inversion. Just like school. I also love to hear the sound of the tubes singing, but never really understood where the vibration to create sound comes from.

love this video and how you put everything together to make it safe for beginners like me when dealing this type of circuits. my request is to show how tube tester works. Have a couple of Ampex 620 laying around that need rebult

Subscribed Sir...very informative. Thank you Sir.

“10 minutes of theory, and 16 minutes of hands on...” Don’t forget the minute spent looking for Jack! 😻

I've got two dual-channel Oscilloscopes in my collection of test equipment, one is a solid-state 20Mhz DSE Q-1804 I bought back in the late 90's, the other is an old Telequipment D33R 15Mhz Tube Oscilloscope that needs a new CRT and some restoration work done on it, they really are useful pieces of test equipment to have, once you know how to use them properly, having the ability to see how a circuit is actually behaving is like the difference between working blind and working with 20/20 vision.

I appreciate your methodical approach to introducing us to a CRO. I particularly appreciated you saying things like BNC Connector, in a manner which could be understood. I am working with model trains and considering purchasing an Oscilloscope. I am hoping that such a device could record a sequence of events, and allow me to play them back. For example, a Capacitor Discharge Unit (CDU) charges a large value Capacitor (I'm using 10,000uF, 63Volts), by directing a supply voltage of 16VAC through a Non-polar 220uF 50Volt Capacitor, thence splitting the flow to two diodes pointing in opposite polarity, which charge the big capacitor. I wish that I could include the schematic, but you can probably get the idea. After a couple of seconds, the big capacitor is changed to about 44VDC, and is ready to supply that jolt of power to a Solenoid, to change points. I would like to be able to record that couple of seconds, and play it back in slow motion. I am hoping that an Oscilloscope could do that for me. Thank you for an interesting presentation. I hope that you, or one of your subscribers might respond to this entry, Arthur

Awesome! No more scared about Oscilloscope. Great teacher, really easily to understand. I was wondering here... If you start to talk about space travel using these old amps, probably we'll learn some cool things. XD

Enjoyed your teaching active passive termonology also love bld race engines trying to apply this wave form todiesel injector trim scan great teacher

The clipping point is also dependent on the strength of the input signal. Electric guitars don't output anything near +/- 2V, so that's why it went into clipping at such a low volume as the signal generator is overdriving the input compared to what it was designed for. Another great video, Doug, thanks again!

Thanks for the video. They are very informative and enjoyable. I am very familiar with the use and application of multi-channel DSOs (e.g., Snap On: Vantage, Vantage Pro, Modis, and Verus; and PicoScope) in connection with automotive diagnostics (injectors, ignition coils, fuel pumps, cam/crank sensors, in cylinder pressure diagnosis, et al.). The Snap On offerings evolved to be very good. However, the industry standard, in my opinion, has become the PicoScope because of its many capabilities. It is my understanding PicoScope makes a full line of DSOs. I don't know if these would be suitable for tube amplifier diagnostics, i.e., overkill, but having experience with their automotive version, it seems they would be a very useful tool. Cheers.

As far as output transformers, when I have instructed fellow musicians in the past on the concept, and they are staring at me like I am an alien with three eyes and green hair, the analogy of an electronic gear box seems to make the light bulbs come on. The conversion from horse power to torque with a gear ratio to climb a steep hill (and the speaker transducer is a mighty steep hill for the poor power tube) does provide a tactile concept for them. Great video as always, Uncle Doug!

Love my tektronix 2232. Owned it first and after learning on the old-school I have a 200 MHz DSO that I use most of the time. But I love how the buttons click. The DSO is not the same. Wish that the modern ones had detents for the knobs.

WOW Thanks I was just about to scope plate voltage This is so much better and safe r

Another great tutorial Uncle Doug. Jack is a black ninja cat so his skills shine better under the cover of darkness. 😁 Thanks for your time.

Lo'der UD ! I smell an Honorary Diploma in "Ampology" coming soon ! Your dulcet tones and ageless wit and humor continue to both impress and educate. I'm only hoping you'll give my Vox clone design a look when it's ready and help me source the difficult bits like Diodes from Mullard for full wave bridge rectification. But in the mean time I will share with my friends and enjoy and wait for the video delights yet to appear. Robert aka jj Thanks ever so......

I eagerly await each and every performance by the great Jack (hairy) Catdini, master of illusion, escape and international cat of mystery.

Yippie! I got a front row seat today

Great videos Doug. I can now switch on my Tektronix T912 without trepidation ! Incidentally, I'm told my 'scope has a storage function - not sure how to use this yet. Another video perhaps ?

Great teaching video, I love scopes, I have 3 of them ! :o)