Understanding Vacuum Tube Amplifier Schematics - Basics - Part 1

[@qek191]

Thank you. Even after 6 years of posting, your video is helpful to people like me, and will do as long as you tube exists. Thank you again.

[@Baghdadbatterymusic]

This series is absolutely incredible. What a time to be alive where this niche info is so easily accessible. Thank you for putting together this series! I love that you don't assume your audience has any prior knowledge on this subject, and instead of either assuming we do or going over every little excruciating detail - you guide your audience to the relevant materials IF they need to review it. You are an excellent teacher and I look forward to watching more of your videos. Thank you for your service!

[@W1RMD]

Great job. It's nice to have an actual teacher teaching electronics. Thank you for your service in and out of the classroom! 🙌

[@julesl6910]

I appreciate you having made this, it has clarified some missing pieces in my understanding of it all. Specifically that 120 cycle hum can only be generated after the rectifier, which greatly helps me in identifying issues with amplifiers while repairing them.

[@Spiderelectron]

Thanks! I learned more in 45 minutes than I've done in the past few years about tube amps!

[@robertbarker2458]

SpiderElectron l agree with you he make a brilliant teacher

[@togethermutiny]

Great instructor - could listen to him for hours!

[@alpalmmusic]

This is great! Thirty plus years ago, as a navy submarine sonar technician, half of my job was repairng high powered amplifiers in my sonar gear. Once I got out of the navy, however, I drifted away from electronics. Now I'm getting back into it and don't you know I've become rather rusty at things like reading schematics. As I plan to work primarily on vintage guitar valve amplifiers it's like going to work on scaled down versions of what I used to fix in the navy. This video is a really nice refresher to drag out the information I used to know almost instinctively but has faded due to disuse. Thank you so much!

[@MrDoneboy]

Mark, your in circuit step by step diagnosis, is so clear and concise. My electronics training was solely for solid state. Thank you, so much!

[@NikonCrayzee]

Simply one of the best explanations of a tube amp schematic - very clear, concise and logical - thanks mate!

[@ShookieJay]

The information you provide with your videos is truly invaluable. As an electrician, I understand the working principles of electricity, but have always been a bit intimidated by the complexity of electronics. Your videos have helped me gain some understanding of this stuff, to the point where I feel confident in rebuilding my Pilot 232 power amp. I had planned on bringing it to a shop, but after what I've learned from your videos, I think I will take it on myself! Truly can't thank you enough for providing this wealth of knowledge for everyone to learn from!

[@nathanmontover1436]

I have been messing about with pedal builds and have used the rudimentary info on reading schematics that I got from my father in the 80s. It's been fun and all, but the info i have gotten from watching these videos has made things so much more clear. Thanks, man!!!!

[@salort2934]

I took electronics in the 70’s when tubes still were used, maybe I was too dumb then, or my profesor made things complicated, but I was so confused that I ended understanding very little. Now here, I get a more clear understanding of how circuits work. Thank you I’ll keep watching your videos, I want to build me a tube amp.

[@jaydean5243]

Very definitive explanation of the circuit with vac tubes, @ about 44:00 mins. prior to ending, you showed the current path, however my question is at vac tube 1/2 6N 1P. I understand the function of the Vac tube, so it's my understanding that part of the current feeds via 1K resistor,/100uf cap. to GND which predetermines the amount of current going into the 0.22uf cap and through the rest of the circuit to produce the sound needed. Thank you, Jay

[@clintn6677]

Thank you so much for this. I have my first amp kit being delivered next week. This has cleared up a lot. Now I'm just a little bit overwhelmed and not totally overwhelmed

[@benboruff]

Wow. I had a basic understanding of how tubes worked in an amplifier, but this tied it all together in a simple, practical example. Perfect. Thank you so much!

[@mohare134]

Watched the entire series and have learned more about VT's than I have in other vids over the past few years! Fantastic content and explanations! Finally, a vid series that answers the question "why" or what does this section do. Tip to viewers; watch the vids at 1.25 speed.

[@brentduxbury5814]

Brilliant! Thanks so much. Your delivery was pitched exactly where I needed it to be for what I was looking to understand. Over the years I’ve gathered lots of good snippets of knowledge and terms about how guitar amplifier work, but your video pulled it all together for me. In particular, there was a real lightbulb moment when you explained how the pre-amp tube amplifies the AC input signal and how the coupling capacitor allows only the resulting AC current through to the power tube. Also, now I understand how negative feedback works. Cheers from Melbourne, Australia.

[@boonedockjourneyman7979]

Outstanding effort. Please just keep it coming. There is a huge need for this on KZbin.

[@dovergerald1579]

Wow! Amazing video. I learned more than I did my entire life enjoying tube amps. Thank you so much!

[@tomaskey6844]

I'm glad you enjoy sharing this info. I learned a lot and will be watching the rest of the series. Just being able to see the signal path through the amp helped me understand quite a bit. Knowing where the signal path went helped make sense of how the other sections worked in conjunction with it. I sure appreciate this video. Thanks for making it and sharing it with us.

[@mangentle7618]

This video is so so great, i have been searching online for years to learn schematics but in vain. After watching this 45 minutes video, i have found my signal path and the reasons why the capacitor and resistors seat there. Thank you so much for the detailed explanations and deeply respect your sharing.

[@willayre1979]

Fantastic video. Its my second time watching this after reading more about ohms law and this time it made perfect sense. Thank you so much for your series!

[@benoySimon]

Just an amazing resource for a beginner like me. Thank you for your painstaking efforts to explain with patience and especially so helpful to understand the 'why's' and the 'how's' . I'm looking at this in October 2022 and am grateful for these series you have put up in 2017. Just awesome. Also interesting comments from other viewers keep the fire burning...🙏

[@ZoopDragon]

This is an *excellent* series of videos. Thank you for taking the time to compile them. I've learnt a huge amount. Please keep them going!

[@utapandgo]

This is great learning - I understood things clearly, thank you heaps.

[@bee17167]

Love your work I am 52 and can remember my pop how was a electronics repair man way back in the seventy's in his shed which I wasn't allowed in if he caught me peeking through the old stained glass window he would chase me but id sneak back especially at night to see the glow from all those tubes he would have some in tester some running in equipment to a five year old it seem to be a scene from a Franking stein movie lost old pop a few years later but now I play guitar and have a lot of tube amps im trying to learn how to maintain them and build one still have a love for tubes Thanks a lot your methods of explaining makes it easy to follow so cool.

[@bobvines00]

Mark, This video (series) appears to be exactly the type of "Tube Basics" that I need in order to be able to understand tube (guitar) amp schematics. Definitely a "Thumbs Up"!

[@836dmar]

Excellent info. Greatly simplifies what so many assume is commonly known.

[@chopper5371]

Going to have to call it a night. Definitely going to watch the next installment. Thank you for the video.

[@rolfwagner601]

Between you and Uncle Doug I have learned a ton!

[@derekgve]

This video is on point. Great job. All of the concepts are very clear and succinct.

[@nightfurynova]

This was the best video I’ve seen and I have a much better understanding now. Thank you!

[@davidcominsky8827]

Most of all thanks for the lesson, So what I learned is to use better quality componets in the signal paths. Already understood basics but the refresh was aok. I liked following the signal paths and understanding what you acheive when you are coupling and I learned a little about tube bias. I will need more here. Anyhow it was just what I needed to get me really intrested in Tube Circuits. Your methods for teaching tube circuits is right on. Thanks

[@williswet]

Thank you. I've been working on tube equipment for 35 years and still have more to learn.

[@martinda7446]

Good video, beautifully described. For anyone interested, the KT in KT88 stands for 'kinkless tetrode' as this has a beam forming plate to correct the characteristic kink in the tetrode curve. This was designed by the MO valve company (Marconi - Osram) in Hammersmith London following the earlier KT66 which along with the 6L6 from RCA in 1936(?) were the first of their type. (I think RCA were first).

[@SOLDbyYOU]

I recover electronics training in high school as an elective “ vocational training” in 1972-1974… we used slide rules…. But electronics did not become by day job so certainly the skill set faded to near zero… I’ve be SEARCHING FOR A good explanation / “re-primer”… of basic audio amps… This explanation was the best I’ve found in weeks of searching… BUT…. The classic mis interpretation / mis representation and therefore the understanding of of electron flow AND THEREFORE SIGNAL PATH… This video does mention this misunderstanding… but I wish that it was stressed every time (especially) signal path is discussed… The signal PATH expressed in mV and then volts as it is amplified… is from grid to anode to grid to anode…. And this APPEARS to be “reverse of positive to negative”… because it is. Otherwise again… the best video I e found. Finally… From my old rusty incompetence… 1) what signal voltages and signal voltage increase might we expect to see along the signal path… And 2) are these volts read as DC… or AC ( I get it , signal is AC… BUT the AC surfs on the back of the DC) And 3) can these signal voltages be read with a better volt meter… and 4) is this safely done by connecting the negative lead to the universal ground and touching the positive meter probe to “ next grid”? Thx

[@michaeldresler1751]

THANK YOU FOR THIS SERIES! I appreciate all the hard work you put into these video's. Watching these have helped me understand all these schematics i see online lol

[@steveball4525]

Thanks for this series, it's most appreciated! Easy to understand for the novice / hobbyist like myself. One thing I would like to see you talk about is phase inverters - when and where they are needed, why they are used and how they affect the circuit. Thanks and keep doing what you are doing, I always learn something from everyone of your videos!

[@Blueglow]

will talk about that when we get to push pull amplifiers, not needed until then :-)

[@mpowrus]

Wonderful video. Both reinforced things i'm learning on my own and clarified things I didn't know. Wish I would've seen this before I looked at my first tube amp schematic

[@ekbanjosworld4926]

Awesome ! Love where you used the math in Ohms Law ! Would like to have seen how the second half of the 6N1P, trying to picture it. Looking forward to push-pull !

[@ekbanjosworld4926]

DUH ! It just clicked while I was making a cup of coffee getting ready for the next video ! The other half of the 6N1P in the schematic would be relative to the coordinating pin #'s and coming from the second signal source ! I'm 61, gimmee a break ! 😂

[@MrWayre]

Great video, thanks so much! I'm working on building some simple tube amps from forums online with documentation. The ones I'm working on explain how to build them but not how they work, so your videos are exactly what I was looking for. Thanks again!

[@wjklaver]

I just found your video :-) I alteady knew how to read electric schematics, but only a little bit about tube amps. Learned a bit more now, thanks for the very good video!

[@1959Berre]

This is a great series. I was never into vacuum tubes, but now I got curious.

[@jameshamilton356]

You are the best teacher. Really appreciate and thank you.

[@fododude]

Incredible video. A lot of information and very well presented.

[@49VinCom]

Thank you so much. This has been an amazing class. It has really cleared up quiet a bit for me.

[@robertcochran7103]

Thank you very much for this series, I want to watch every one of your videos. I have learned so much from this one.

[@oimate4201]

Wonderful presentation of information. I’m brushing up and looking to get back into the hobby (in my case) and I really am enjoying your teaching style. It’s amazing how fruitful the same general information can be received by learning it from different people and/or sources. Thank you and I am looking forward to enjoying more videos from here as I am new to the channel. 🤠🎸

[@marccco96]

I really appreciate this video, this was exactly what I was looking for, I learned more than ever about vaccuum tubes, thanks a lot!!!!!

[@anthonyvolkman2338]

I love your videos! I've worked with tube amps and other electronics for 13 years bit it still nice to "brush" up on my knowledge. Thank you for your hard work.

[@green122s]

Just starting in electronics and really appreciate the time and effort you are making. Will look forward to your upcoming videos in the series!

[@BobSnyderAuto]

Thank you! What a fantastic job explaining this! I learned an incredible amount from your video. Can't wait to watch your other videos! Also looking forward to finding my next broken tube amp so I can put this into practice! At some point I am going to build my own!

[@francismannion7075]

Great video I agree with Spider Electron, I learned more in the short time of this video than hours I spent in school . I am really looking forward to your next production.

[@MrDemuxus]

This is fantastic...i have a selmer zodiac twin 30 which has a fault...blows fuses...original componants so caps are probably needing replaced....you are giving me confidence to investigate and rectify

[@mitchmason8386]

Thanks a bunch this stuff is great. I been learning this stuff pretty much on my own as I try to find where cracking and hissing is coming out of my Vox Ac15c1. Still haven’t completely harnessed the noise but this video has definitely been very helpful

[@TheOpenAirGarage]

Very glad to see you offer this. I appreciate it and I am looking forward to the next installment.

[@JackSmith-ud9bg]

Thank you for these series. I will be watching and hopefully learning a lot.

[@UDX-21]

Thank you for taking your time for everyone.

[@soapboxearth2]

Thank you !!! I needed this as a new builder. So many questions need answering lol

[@steelcantuna]

I have really enjoyed watching the first 4 parts in this schematic series. I will continue to watch the rest. Have you ever considered showing how to "trace" the actual physical components in an amp or tube radio in reference to the schematic??? I mean, reading the schematic is one thing. Actually finding the particular resister or cap, etc. in regards to the schematic "map" is another thing. As you well know, the schematic will (sometimes) make it look like a particular component is sitting right next a certain cap or resister. In reality the the other component is way across the physical chassis hidden behind some other component. Also, there is very little (if any) instructional videos concerning working on old 50's & 60's Lesslie amps. I think this would make a great instructional video. These are still very popular amps. Thanks

[@zgoume]

Awesome video! I'm getting into learning how guitar tube amps work in order to try to build one myself, and this video helped a lot in the understanding of how vaccum tube amps work! Cheerz from France!

[@joseluis5150]

Great video! thank you for sharing your knowledge with us!

[@tonguedarts]

Excellent video. Very informative, concise, and we'll spoken. Thanks!

[@whiting444]

Absoutely great, have been waiting for something like this for a long time. Much appreciated and keep them coming around this tutorial concept for beginners.

[@gcaligula6653]

I have learned a lot from this video. Going to watch part 2. Thank you

[@jdsalinger73]

Wish I had this tutorial when I learned about tubes. I used a late 1940's US Navy Technician 3 hand book. A little dry, but I got it.

[@emtee8172]

Excellent video packed with info that I can follow and understand. Thank you!

[@xXBocephusXx]

Excellent video! I'm looking forward to the rest of the series. Thanks

[@superfunchile7965]

thank you very much! short story, i found some in the land field, took me a week to research what they were and how they work; finally trying to use them to turn a AC from a wind generator also from scrap to DC to 12V :) hope it works! Aloha

[@bennoheritt8154]

allways, fine videos and tutorials.

[@TheSoundtec]

Excellent.. Love how you explain the signal path

[@arthurharrison1345]

Fantastic! Thanks for such a great tutorial.

[@leesanders6490]

Watching this video I realized that the B+ to ground was serving as a carrier for the much smaller AC audio signal. Breakthrough! Thanks!

[@dreamliver750]

Best channel on youtube

[@davidhitillambeau3759]

Thanks for this great content. The explanations are very detailed and accurate. I have a few questions though: 1) is B+ connected to the anode of the (half) 6N1P positive DC while the B+ connected to the output transformer negative DC? 2) where is the input of the (half) 6N1P cathode on this diagram?

[@shawnjoe72]

Thank you for this tutorial. It is helpful with some stuff. Other stuff I just have to rewatch till I get a better understanding of it all. Its a lot to intake at once.

[@johnwoodland7153]

thanks. looking forward to following a push-pull amplifier project.

[@johnbravo7542]

Blueglow,thank you so much,you have answered a lot of questions I had in my mind :-)

[@markpixley4009]

Great video covered the important things very well, thanks!

[@michaelevans3852]

Thank you for this! I have little experience with tube amps, but much with wiring homes. I recently purchased a 1960 Fender Concert and the Vabrato doesn't work. This is what began me looking around. This has been helpful. Could you talk about the Vabrato on my Concert?

[@henniecronje3212]

Thank you very much. Truly appreciate the hard work.

[@petert6061]

Great video. You're probably cover it later but I was just thinking of signal phase.

[@Jackstraw125]

Spectacular post. Thank you so much for doing this. My only question is how are the values for the coupling capacitor between the stages calculated and also how are the capacitor values for the cathode capacitors in parallel with the resistors chosen?

[@Schwalar]

Very nice! Looking forward to seeing the rest of the series! One question though, how do I know what transformer to use?

[@inception-hifi]

Great! Thank you! clearest explanation!

[@parachuteman4]

Excellent explanation!

[@analogueheavenrecordingstu2984]

Amazing video thank you so much. You explain things so clearly. I have just started building guitar effects pedals and my dream is to be able to build a hi fi amp like the kt88 one here. Thanks again

[@terrypokorny3858]

i just stumbled accross this vidio and it will be of great help to me. I am trying to build a regen receiver and add an af amplifier using a type 30 for the amplifier tube and i am trying to figure out the coupling cap between the 33 and 30 tubes

[@jordanrenaud-pq7rx]

very effective lesson maybe the best online or anywhere

[@carltrummer9103]

Thank you very much for this video; very instructive.

[@annazolkieve9235]

Thanks for the video! Newbie is here, please be patient. 42:25: "it could be 20..30 volts": If the output voltage is about 20..30 volts, then why there is a need of so high input voltage, which is 400 volts? The concern is that the weight of transformers is about 60..70% of the total weight of an amplifier. Is it practically possible to reduce these 60..70% to, say, 10-30%? The benefits are: less weight, less (useless) heat, less price, etc. If the reason goes to the tubes, then are there any tubes on the market that can operate on a less voltage? Thanks.

[@richardmawdsley2589]

Great for a novice like me, thankyou very much! Although i do get confused as to which parts are AC and which DC.

[@edsanders9605]

Really, really nice- VERY much appreciated!!!!

[@josealphonso2848]

I like to give 👍👍👍 for you video. If my physics teacher is half as good as your lecturing, I will take up electronics instead of chemistry.

[@trevorlangley7988]

Great video - thx for sharing!

[@TerryClarkAccordioncrazy]

You are a great teacher.

[@surendersingal2192]

Thank u sir, great explanation on basics.

[@darrenbird2526]

Fantastic tutorial, Cheers!

[@franzleone]

I have learned a lot! Thankyou so much

[@hypnothang]

Thanks for your time and expertise