It will ensure any small amount of DC that might leak through the coupling cap is grounded though the pot. In a perfect world, there should be no DC but I've seen caps as they age start leaking DC. You never want to have an "open ended" cap connected to the output for that reason. It also provides the ground path to shunt a/c signal for volume control.
Thanks for starting this series. It's easier and more fun to listen to you explaining stuff than reading about it :-) Looking forward to more of it, and also that 47 OT built in that amp.
Thanks for this! I’m looking forward to the next in this series. Gonna get another coffee and watch this a couple more times… Note book and pencil needed - it’s like being back in school, only fun :)
I’m just getting around to watching this, but your a good teacher. If you think about it, most things have there own language. A friend of mine is a commercial pilot. He said learning to fly the plane was easy, but learning the language was Hard. This is no different, plate, cathode, grid, grid stopper, bypass cap, on an on. I think when I master an totally understand the language, the rest will become easy. 🤷♂️
Very good 👍. I shared this video to my friend who is a professional guitar player and owner of an appliance repair shop. He understands power transformers relays and motors and a lot about basic electricity. I told him a tube is a lot like a relay in that it controls a large current with a small current. The only difference is it conducts only in one direction and can vary its conductivity rather than just on and off. The heater makes the electrons very uncomfortable to be resting on the cathode which cause movement in only one direction towards the plate. He wants to understand how electric guitar amps work. I also told him how dangerous they are to work on and to leave the factory made ones up to me. Maybe I'll build him a low volume type that works on about 75 volts. He plays hard rock so that would be perfect for over saturation and maybe not damage the ears and he can experiment with that instead of 400 volts
Can you discuss the dangers to the output transformers with running tube amplifiers with out a load....and the benefit of adding 100ohn resistors to the output for protection.
Good tutorial! Would love to see a phono tube preamp with compensation adjustments. Years ago, I had a Fisher 50-c3 I bought at a yard sale and lost track of it after a move. It was passive, and sounded great. It was mono and used 2 12ax7s and one 12au7 with a solid state rectifier.
Hi, I have only recently found your channel, I’m finding it very interesting as you explain what’s going on in a down to earth way! I’ve been curious as to how Tubes or Valves (as we call them here in the Uk) work ever since I was a kid! I’m not very good on the theory side of things, although I have burnt many a hole in the carpet with a soldering ion! I managed to pass the Ham radio exam in 2003 learning by doing and taking old radios apart to see what was inside. Anyway I’m now retired and am getting into Valve Amplifier’s and have recently built a kit Amp, but on testing, one of the bias caps and resistors went up in smoke, it’s being looked at by someone with more knowledge than myself, but I’ve been informed that it may be faulty valves or other components, and not my construction. Since then I have purchased a Muzishare X7 which I really like, and I saw on the facebook group that you are going to make some videos about that Amp, so looking forward to seeing that. It’s going to take me a long time to watch all your videos, but I’m sure they will help people to get a better understanding on how Amps work. All the best and good luck with your excellent channel! Alex
Howdy. Great. Looking at the spec.s I observe the 12AY7 is more linear than 12AX7, though less raw gain. This is pretty much what I have been looking for. I should think it is more stable than 12AX7 with strong neg. feedback. Regards.
Thanks for the videos, In the EAR 834P phono stage, I’ve seen some people substituting a 12au7 or a 12at7 in the #3 position (cathode follower), any thoughts on this?
@@SkunkieDesignsElectronics If you adjust the cathode resistor value it will clip off the negative cycle, if you adjust the plate resistor value it will clip off the positive cycle. Both cathode resistor and plate resistor are biasing the tube in its linear operation but I think its called the "AC load line"?
Not how this works, rewatch the video. Maybe SS stuff works that way? The cathode resistor simply sets the bias point on the load line. And this isn't showing a phase splitter, this is a simple voltage amplifier.
@@SkunkieDesignsElectronics without the cathode bypass capacitor you mentioned in the video that "without the cap" it changes the DC load line bias point because the current flowing through the tube is NOT stable. The "AC load line" bias point is determined by the cathode resistor value and plate load resistor value, is that correct?
I have no idea what you are thinking or trying to do here. I explained this as simply as I know how. This is a BASIC "how a tube works" not a master class. I'm done. No idea where you are going with this "AC load line". This isn't an output tube.
Newbie question: so you're dropping the plate voltage enough to maximize the potential swing? Cutting it in half makes sense because ideally it could go from 0 to +280 V.
Thank you. This is great explanation of how the plate and cathode resistors function in the tube circuit.
Glad it was helpful!
This was very helpful. Have watched many explanations over the years, yours was the one that broke through this old bone vault.
Great explanation and display
14:00 the DC is referenced to ground, confused, where does this DC come from?
It will ensure any small amount of DC that might leak through the coupling cap is grounded though the pot. In a perfect world, there should be no DC but I've seen caps as they age start leaking DC. You never want to have an "open ended" cap connected to the output for that reason. It also provides the ground path to shunt a/c signal for volume control.
Thanks for starting this series. It's easier and more fun to listen to you explaining stuff than reading about it :-) Looking forward to more of it, and also that 47 OT built in that amp.
Thanks for this! I’m looking forward to the next in this series. Gonna get another coffee and watch this a couple more times… Note book and pencil needed - it’s like being back in school, only fun :)
Awesome! Thank you!
Excellent!
This was extremely helpful for my basic understanding of tube amp design! I hope for more!!!
I'm addicted to your channel!!!
There are more edu videos in the playlist this video is a part of.
I’m just getting around to watching this, but your a good teacher. If you think about it, most things have there own language. A friend of mine is a commercial pilot. He said learning to fly the plane was easy, but learning the language was Hard. This is no different, plate, cathode, grid, grid stopper, bypass cap, on an on. I think when I master an totally understand the language, the rest will become easy. 🤷♂️
Thank you for putting so much time and effort into your videos. Great content. I’m thrilled to see how your UA-cam channel is taking off.
Very good 👍. I shared this video to my friend who is a professional guitar player and owner of an appliance repair shop. He understands power transformers relays and motors and a lot about basic electricity. I told him a tube is a lot like a relay in that it controls a large current with a small current. The only difference is it conducts only in one direction and can vary its conductivity rather than just on and off. The heater makes the electrons very uncomfortable to be resting on the cathode which cause movement in only one direction towards the plate. He wants to understand how electric guitar amps work. I also told him how dangerous they are to work on and to leave the factory made ones up to me. Maybe I'll build him a low volume type that works on about 75 volts. He plays hard rock so that would be perfect for over saturation and maybe not damage the ears and he can experiment with that instead of 400 volts
Thanks! For your contribution, I love the way you make it easy to understand all this knowledges. Please keep on doing…
Very informative
Thanks again!
Glad you enjoyed it!
Uncle dug is cool
Thank You for that great explanation. Cheers!
Fantastic explanation! Thanks a bunch
Glad it was helpful!
Can you discuss the dangers to the output transformers with running tube amplifiers with out a load....and the benefit of adding 100ohn resistors to the output for protection.
That's a good topic to cover in a future video!
Thanks so much - this was very useful. You should put it in a an education playlist now or once you do your next one on capacitors!
ua-cam.com/play/PLtEhh3UpOsiDdHABS0q5byT2gAQ5z31Hk.html
Wonderful explanation. Where to find the other studies video? Thank you very much.
ua-cam.com/play/PLtEhh3UpOsiDdHABS0q5byT2gAQ5z31Hk.html
@@SkunkieDesignsElectronics Thank you very much.🙂
Good tutorial! Would love to see a phono tube preamp with compensation adjustments. Years ago, I had a Fisher 50-c3 I bought at a yard sale and lost track of it after a move. It was passive, and sounded great. It was mono and used 2 12ax7s and one 12au7 with a solid state rectifier.
Hi, I have only recently found your channel, I’m finding it very interesting as you explain what’s going on in a down to earth way! I’ve been curious as to how Tubes or Valves (as we call them here in the Uk) work ever since I was a kid! I’m not very good on the theory side of things, although I have burnt many a hole in the carpet with a soldering ion! I managed to pass the Ham radio exam in 2003 learning by doing and taking old radios apart to see what was inside. Anyway I’m now retired and am getting into Valve Amplifier’s and have recently built a kit Amp, but on testing, one of the bias caps and resistors went up in smoke, it’s being looked at by someone with more knowledge than myself, but I’ve been informed that it may be faulty valves or other components, and not my construction. Since then I have purchased a Muzishare X7 which I really like, and I saw on the facebook group that you are going to make some videos about that Amp, so looking forward to seeing that. It’s going to take me a long time to watch all your videos, but I’m sure they will help people to get a better understanding on how Amps work. All the best and good luck with your excellent channel! Alex
Thanks for the nice comments :)
Gold! Thank you!
Thank yoi very much by the explanation!
This is very useful. Thanks for sharing your knowledge.
Thanks for the education video, it's very wel explained 👍
Yep complex but all learning is complex. I appreciate learning I’m getting a lot from you thank you very much.
Thanks for watching!
Howdy. Great.
Looking at the spec.s I observe the 12AY7 is more linear than 12AX7, though less raw gain.
This is pretty much what I have been looking for. I should think it is more stable than 12AX7 with strong neg. feedback.
Regards.
None of my single ended designs use strong negative feedback.
Very well explained.Thanks alot.
Can't wait for the Cap video
Thanks for the videos, In the EAR 834P phono stage, I’ve seen some people substituting a 12au7 or a 12at7 in the #3 position (cathode follower), any thoughts on this?
I haven't tried that. I'm using 7025, a Motorola in #1 and RCA in #2, #3
Perfect. Thank you.
The Cathode electrode and Plate electrode form a capacitor? the 1.2K cathode resistor is called a Load Resistor which clips off the negative cycle?
The load resistor is on the plate. The cathode resistor is simply to create a negative bias between the grounded grid and the cathode.
@@SkunkieDesignsElectronics If you adjust the cathode resistor value it will clip off the negative cycle, if you adjust the plate resistor value it will clip off the positive cycle. Both cathode resistor and plate resistor are biasing the tube in its linear operation but I think its called the "AC load line"?
Not how this works, rewatch the video. Maybe SS stuff works that way? The cathode resistor simply sets the bias point on the load line. And this isn't showing a phase splitter, this is a simple voltage amplifier.
@@SkunkieDesignsElectronics without the cathode bypass capacitor you mentioned in the video that "without the cap" it changes the DC load line bias point because the current flowing through the tube is NOT stable. The "AC load line" bias point is determined by the cathode resistor value and plate load resistor value, is that correct?
I have no idea what you are thinking or trying to do here. I explained this as simply as I know how. This is a BASIC "how a tube works" not a master class. I'm done. No idea where you are going with this "AC load line". This isn't an output tube.
Newbie question: so you're dropping the plate voltage enough to maximize the potential swing? Cutting it in half makes sense because ideally it could go from 0 to +280 V.
yes
Great stuff :)
that was awesome
Now I know why they put cathode bypass caps are in the cct...thanks :-)
Glad to help
Ciao ciao , I follow you with very, very, very interest you are too strong kisses from venice
Thanks for watching!
This beats Uncle Doug by a mile
Two completely different approaches.
Uncle Doug does a great job as well......!!
Great video 🤠
Tubes are just Hippie-Transistors.
:V
High-voltage JFETs with a grid and a heater.😊