I'm learning about superhet and vacuum tube circuits in order to repair an antique radio I inherited. Your videos are better than many of the "high brow" ones I've come across. I like your hands-on, direct and practical style. Although I worked for 20 years as an electronic technician, I never dealt with vacuum tubes or radio before.
Thank you. Here are some other videos that may help. The last link is my FREE ebook. The password is allamericanfiveradio Let me know what you think. Triode Tube Amplification Visual Demo ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-4FkD0LRiu7A.html Control Grid, Triode Tube ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-K_AJRIsNlR0.html How Superheterodyne Works ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-jQd2LfTOa4k.html Password is allamericanfiveradio ru-vid.com?event=channel_description&redir_token=QUFFLUhqa2hhVTRycWdJd1FUbTFCZWNmdGtQNlZCRmEzd3xBQ3Jtc0tuOFQ2bFhRcWdjdUdIcUREcnZFaHc0M2xURGhITVRuWDE2cGlDakdYUF9uODktNzc3TVRJTWdROUt6R3NLN2lla3hFS2lIM0RnOXR1dXFxMGx2cUNtWDhXb1Zvc2RCbGQxTThoendmN2E5R0lJdmI0Yw&q=https%3A%2F%2Fdrive.google.com%2Ffile%2Fd%2F1HHmaWYr7UMACfmS4W5uL6PADoem2KlRp%2Fview%3Fusp%3Dsharing
Thank you. You may like my FREE Ebook, it is PDF. Here is the password and download link: Password is allamericanfiveradio ru-vid.com?event=channel_description&redir_token=QUFFLUhqa2hhVTRycWdJd1FUbTFCZWNmdGtQNlZCRmEzd3xBQ3Jtc0tuOFQ2bFhRcWdjdUdIcUREcnZFaHc0M2xURGhITVRuWDE2cGlDakdYUF9uODktNzc3TVRJTWdROUt6R3NLN2lla3hFS2lIM0RnOXR1dXFxMGx2cUNtWDhXb1Zvc2RCbGQxTThoendmN2E5R0lJdmI0Yw&q=https%3A%2F%2Fdrive.google.com%2Ffile%2Fd%2F1HHmaWYr7UMACfmS4W5uL6PADoem2KlRp%2Fview%3Fusp%3Dsharing
Rick - another one of your amazing illustrated tutorials that keep things simple and easy to follow. As always, thank you for taking time to share your knowledge with us. All the best. Don
Wow what a great little radio! Excellent sound as well. I love seeing the avc in action. It's amazing how they had this technology in the 30's, yet commercials in modern tvs blow your eardrums out!
Holy smoke .... I built one of these when I was in school learning about electronics back in 1968, then we went on to transistors then the first wave of IC's .... well any way the soldering iron was a huge 100 watt thing ..... lots of fun back then .... LOL LOL
I had forgotten all about the really old Superheterodyne receivers that had tube filament voltages that added up to the mains voltage. One tube's filament opens and Poof, there goes the receiver until you pulled out the ole tube tester and found which one had opened up. I was glad when more radios started having power transformers to isolate the mains from the secondary power outputs.
Very good. When covid started I had the pleasure of restoring a 1946 Philco tabletop radio that was similar to one I had as a young boy. I was able to see signals similar to these. Thanks.
This brings back memories, in college our class built the AA5 radio and after getting it working and tuned, the teacher and assistant would bug them and return them for us to troubleshoot. They complained that mine was difficult to bug because my wiring was too neat. I had built many kits prior to college so making it look good was easy for me.
Wow! Finally! I never understood how superheterodyne works, i could not get around the mistery. This is a very informative video. I get it now, it's not that hard to understand when it is explained like this. I am very gratefull for your video! Thank very, very much!
Glad to have this on youtube, a fantastic explanation of such a classic radio circuit, thank you very much! When measuring variable voltages like the AVC regulating voltage, I personally find it useful to use a analog multimeter instead of a digital one. The range of the needle movement on the scale is maybe more meaningful. But when measuring steady voltages or currents, like the measurement of filament voltages, plate or screen grid voltages, I prefer to use a digital voltmeter. When measuring the AC ripple on top of the DC voltage of the output of the rectifier stage, a digital voltmeter would be the very best choice. Best regards from Switzerland, bluearcturus
The "gold standard" of the time was to use a VTVM and look to peak the IF outputs. It still is the thing for any tube-type radio gear. No restorer or ham's bench should be without one.
I was given one by a relative when I was a kid. I modified it to take an octal socket with different coils so I could also tune the SW bands. Loved that thing. The smell, glow and warmth of all those tubes added to the mystique.
A well kept secret is that the technique demonstrated here with measuring the AVC is the quick, hassle-free, way to peak out the signal in doing an alignment. No having to keep the signal level low in order to avoid invoking the AVC effect. Thanks, Mr. McWhorter, for your outstanding videos and books!
Thanks for the video, it's hard to retain all that's going on in these radios. I still need to watch these type video's to learn and maybe someday remember what's going on in there.
beautiful contribution of superheterodyne amplitude modulation receivers reminds me of my years as an electronics student when our professor victor peiroti taught us the theory of superheterodynes with their tandem variable capcitor the local ocildor coil the intermediate frequency transformer the 1n34 diode that he used to audio demodulator that separates the audio from the radio frequency of the IF. how many memories. the mathematical equations the formulas thanks for the video. Kind regards from Argentina 👍🙏📻
Thank you, and your welcome. I'm glad you found this video useful. I do have FREE eBook that also may find helpful and useful. The link is in the ABOUT on my RU-vid site. Here is the information for the eBook. I hope you enjoy and find the information useful. PASSWORD is allamericanfiveradio drive.google.com/file/d/1HHmaWYr7UMACfmS4W5uL6PADoem2KlRp/view?usp=sharing
I found an old guitar amp in the trash the other day. It contains a 12AX7a Twin Triode. I have no idea what to do with it. I'll have to re-watch all your tube amp videos!
Local oscillator TRACKS incoming station frequency such that the DIFFERENCE between the two signals IS 455KHZ. This is why the variable has 2 section GANGED together. Reason why a certain frequency picked had to DO with component size. RCA patented 455KHz so others had to pick another IF frequency so no royalties would have to BE paid. AVC influence has to BE kept low while peaking IF coils. Pick really faint station, pipe in the IF frequency and peak. LOL The rectifier removes half the carrier envelope so that the audio extraction can take place. There IS so much going on. Always learning. Good video info.
So in the first tube starting at the bottom you have the cathode which feeds the inductor that feeds the tank circuit. You mentioned this was DC power but the inductor needs AC current if the local oscilator is to function? Also if I understand correctly the screen grid is the transmission signal and the control grid is mixing the LO. What are those other 2 grids that appear to be coupled together on pin 6 of the first tube, they appear to be part of the IF tank circuit?
Hey Ron, we must be amphibious or something. I am currently working on drawings for the oscillator circuit. I had a request from a RU-vidr to go through the oscillator circuit in more detail. I'm hoping to be able to upload a video may be this Sunday. I'll try to remember to let you know when I have uploaded a video in a comment on this video.
@@AllAmericanFiveRadio Thank you so much, this is super helpful to build my intuition of how this works. Once I get about 80% on the tube heterodyne I have to learn the solid states. We have a Harris HT20 and BT35 Transmitters
I was slightly confused by your statement that "The secondary is hooked up to a diode". I searched from the output of the secondary's coil thru the circuit but did not see a diode anywhere. Then, a little research for the 12AV6 tube data reveals that this tube contains both a triode and 2 separate diodes - internally, the diodes being connected to tube pins 5 & 6. Looking at your diagram, pins 5 & 6 do appear to show as diodes inside the tube. Therein lay my confusion, the IF secondary is hooked to a diode, which is integral to the tube, not a distinct, external component separate from V5. I may be dense but perhaps this will help another so confused. Great video otherwise.
Could it be said that the capacitor to ground is a high pass filter sending high frequencies to ground? But you were talking about amplitude of the signal not frequency
I have often wondered why it was that automobile radios had a 262khz IF strip. Would you happen to know the answer for that? I'm stumped on it. My 1972 Philco Ford AM only radio has it. Great radio by the way. Very selective and sensitive.
@@AllAmericanFiveRadio So inside V5 is the diode, when it’s connected thusly? Ah ha… tricky that. I had to look up the tube to research it and find it has two diodes in it. I searched your diagram a long time for a diode on its own. Ha ha
Oscillators, the Basic Tank Circuit 1 ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-fQ4yRVEzXQA.html LC Tank Circuit ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-8vu9WDjBAho.html AM Transmitter Tank Circuit Coil Capacitor Resonance ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-6TRqNkT5OCk.html Radio Oscillator Tank Circuit ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE--Q-gvhErkcY.html
