Create And Build An Electronic Circuit!

[@MrCarlsonsLab]

To learn electronics in a very different and effective way, and gain access to Mr Carlson's personal designs and inventions, visit the Mr Carlson's Lab Patreon page here: www.patreon.com/MrCarlsonsLab

[@jamesengland9824]

Why not add a audio delay relay NO on the output of your amp. After the amp is stable allow the relay to close.

[@jamesengland9824]

Oops, after watching this video you are adding the exact circuit!

[@Dennis35793]

Good job

[@kerrymullin6978]

How about using a DPDT relay and putting the red and green LEDs on the second pole. That would eliminate some parts and give you feedback that the relay is actually energizing. Just a thought.

[@tee-jaythestereo-bargainph2120]

I would love to review this amp ! Nice job Mr.Carlson ! Me have many speakers 😆

[@OceanEady]

Hey Mr Carlson, I just wanted to say thankyou for all the free education you've uploaded over the years on this channel. I'm a high school student and your videos and knowledge on electronics has provided me with hours upon hours of informative, useful and practical advice. Keep the videos coming! A lab that looks like yours is a dream of mine I hope to achieve one day.

[@southjerseysound7340]

He really is one of the best there is. Granted there's others like big clive that are fun too. But when it comes to learning he can't be beat.

[@chrish282008]

I've done electronics for 50+ years, I know everything there is to know. I listen to Mr Carlson and it makes me realise just one thing..... I know nothing about electronics at all🙃

[@BruceNitroxpro]

Chris Handley , You, too? ROFL

[@frankowalker4662]

Yeah. (he said, depressingly. LOL)

[@the8bitbarn836]

I've been working in electronics for about 40+ years and I've never been able to say I know it all! I learn things every day about things from basic principals to complex formals and circuit designs. Don't worry about what you know, worry about what you don't know and above all else never be afraid to ask someone if you don't know! Keeping an open mind brings you closer to a solution than all the thought and doubt in the world! Mr Carlson thank you for sharing!

[@miroslavstevic2036]

Frankly speaking, these are really basic things. There is no math at all. Even the basic electronic course we had at the University is full of complicated calculations, feedback, transient and small signal analysis. Electronics is nowadays much more than repairing some old stuff. If you take AC vector drive for example, complicated math transformations are the most important things. Actual switching bridge means nothing if you don't know when to turn on the transistor. It took me less than an hour to understand the depth of my ignorance. Although I know at least 100 times more than 20 years ago, I can't tell that "I know electronics", especially to know everything. I know 10% of the books I have, and the books are less than 1% of everything that exists.

[@the8bitbarn836]

@@miroslavstevic2036 So true. All the math that I learned for electronics seems kinda pointless now, studied logic theory and calculus point curves all of that. a lot of what I learned doesn't apply anymore, FPGAs, Asics, DSPs, and Micro controllers do it all now. Its more of component selection than actual design. There's not much calculation being done as far the actual construction of a circuit. The world isn't analog anymore it's digital. What electronics is today is cost based, life spans are shorter and the disposal factor is higher. We use and then we toss it out. Well that's my rant for today thanks listening!

[@empathicallyyours4937]

Mr Carlson, you're not fussy at all, if I may say so, you're absolutely proper in the most necessary way. I know so little, but I enjoy listening and learning as much as I can. Gigathanks!

[@Crobisaur]

I'll shamefully admit that all of the EE knowledge I learned during undergrad & my masters was blown away in the first 2 minutes of your design process. I've spent so much time on embedded software design I never explored how to do very simple things with small & discrete components. Love your content and thank you for walking through your design process so nicely!

[@elektrolyte]

to quote Bob Pease: “My favorite programming language is solder ..." ;P

[@MechanicaMenace]

Everyone has a preferred toolset. There's nothing wrong with yours. Especially as you can obviously appreciate others mastery of theirs.

[@BruceNitroxpro]

@@elektrolyte , Well, I thought that was funnier than hell! LOL

[@mackfisher4487]

Mr. Carlton's Lab KZbin audio quality: now I'm starting to get some insight into why your presentations have such great audio.

[@killer1479]

turning his monitors on before the amp and hearing the loud THUD, is the reason his hair is like it is :)

[@MrCarlsonsLab]

Yes!

[@fadingbeleifs]

🤣

[@VoCodebcv]

As a professional Voice Actor, I've always recognised the need for flat response non-colored audio. (That, and my vintage radio addiction.) I've often wanted to comment on your voicing excellence. This gave me a great opportunity.

[@Lambda_Ovine]

I need more videos of people drawing schematics while explaining the why and the how. So damn informative.

[@Eon119]

When I was a kid (some 40 years ago!) it took me a long time to figure out how to use transistors. I used to go to the library and look at the books, but it was like another language. In the middle of this video where Mr Carlson explains the transistors, I would have understood this straight away. His explanation is in clear simple English. I so wish I'd had access to this style of teaching back in the day.

[@Watchyn_Yarwood]

👍👍

[@spudhead169]

100% agree.

[@adamwolfram6126]

I would love to see a Mr. Carlson video on drawing tube load lines and composite load lines, and how they relate to the next stage. The few videos on the subject on KZbin are pretty tough to follow or are poorly directed. I'd love to see his quality and style of teaching brought to the subject.

[@AudioFanMan]

Bump!

[@therealdjryan]

The videos where you’ve shown the design process are always my favorite.

[@bradleysmith681]

Love watching you walk through a design so that we can understand the thought process. Helps much! Please do many more similar videos!!

[@gwesco]

Ignition points! I built a Tiger CDI system for my old Datsun 240Z and once when I took it in for a tune-up, the mechanic said he needed to replace the points, not because they were pitted but because the rubbing block was nearly gone after 60k miles. The points themselves were nearly spotless. I'm an old gearhead who in my waning years have embraced EV's due to not wanting to crawl around under them anymore. Grew up on vacuum tubes and still teach computer science.

[@MrCarlsonsLab]

Thanks for sharing your story George!

[@patprop74]

A Mr. Carlson's video is always a good excuse to take a break from work for!

[@mdevries8495]

Excellent video, 30 seconds dead on... If this we're a commercially oriented channel I would've rolled my eyes. Now I'm just amazed.

[@SN-1006]

The first vid i have seen from you was the vid about the ice rain you've had on Christmas/new years eve 2017. Never missed a video since then. Top quality productions with a host that knows the hell what he's doing. Keep the vids coming, your work is very much appreciated. Much love from germany 😉.

[@Michael_Michaels]

Mr Carlson is my favourite Ghost Buster!!! Just look at all those apparatus??? But now, without trolling, thank you for sharing your amazing wisdom!

[@jond1536]

Oh my gosh, I would like to see a conference with Mr. Carlson and Louis Rossmann, it would be fantastic as to these two guy working on an circuit board. WOW

[@AnthonyFrancisJones]

A masterpiece of explanation. Thanks so much for taking the effort to make this video.

[@MrCarlsonsLab]

You're very welcome!

[@FluxCondenser]

Like watching DaVinci sketch. Paul, you’re a genius and watching you work and think things out is both fascinating and instructive. You set the standard for KZbin audio quality, one that we all strive to achieve.

[@bitrot42]

Nice project, and great walkthrough of the design! Funny how old-school home-etched PCBs go well with modern surface-mount components -- no drilling!

[@amoore2719]

Transistors so common that are probably in the soil in the backyard....Nearly spit my drink on the keyboard! Thanks for the great videos.

[@MrCarlsonsLab]

You're welcome

[@johnbellas490]

Hello Paul!! Another GREAT video as always!! This was a VERY GOOD review of the venerable most prolific 555 timer chip and one of its many applications!! Yea Paul Carlson one of the WORLDS BEST INSTRUCTOR of ALL TIME in my book!! Cheers my friend from John Bellas KC2UVN 73's

[@MrCarlsonsLab]

Thank You for your kind comment John!

[@MrNhojstrebor]

Mr Carlson's Lab I watch a lot of videos on youtube, and I am also a musician, so I have a gut ear for sound. I must say, you're audio quality is by far the best I have heard.

[@MrCarlsonsLab]

Thanks Hans, I appreciate that!

[@InXLsisDeo]

And all that on venerable tube amps.

[@videosparacompartir4195]

Hi! Amazing studio. I am just reconecting myself with my old science passion, after 40 years of ignoring it. Chemistry, physics and electronics. Special old electronics. Just waiting arrival of a vacum tubes osciloscope... Thanks for inspiration.

[@beeman1885]

A little late to the game but a great video with everything explained so well. I tracked with everything except the purpose of the 22k resistor between the 6v3 rail and the base of the transistor that drives the green LED. Heading to patreon to sign up. 👍

[@johnopalko5223]

Great idea running your heaters on DC. That eliminates a whole lot of hum.

[@jkuebler89]

I could watch these circuit design and implementation videos from you all day. Fascinating to watch. Learning from a top notch pro. Thank you!

[@vinitshandilya]

What an amazing video! A small concern. 25:06 PNP switches seem tricky. In this case, the 555 output may not fully swing to 6.3V and if the output difference is more than 0.7V, it would still draw a small amount of current across the PNP base emitter junction. So even when the output goes high, the red LED would continue to glow.

[@MrCarlsonsLab]

The Red LED is fully extinguished.... Very good observation though, if the circuit isn't built just right, what you mention is an issue.

[@thefixerofbrokenstuff]

I dont care if the audio is amplified with psychedelic chickens and filtered through kosher pork chops, its the best audio on youtube. I wish I could say I understood why, but it would be like explaining positrac to a kitten.

[@InXLsisDeo]

I listened to the video through my McIntosh 275 power amp and yes the sound is glorious.

[@thomashowe855]

thank you so much. That’s really all I can say, because the amount I’ve learned from you is immeasurable.

[@MrCarlsonsLab]

You're very welcome!

[@blitzroehre1807]

Thank you for letting us accompany you during your design process, Mr Carlson. Very enlightening. I had to laugh when the trusty 555 came into the scene for the millionth time in a design, I remembered when as a young lad I bought my first one at an electronics outlet in 1974, those $2 whopped into my pocket money , got me sweating at the till :-) But there is no money which can counter the wealth of knowledge gained from cobbling my first simple circuits around this first IC of mine..

[@DarkZoneV]

I always enjoy Mr Carlson's videos no matter about what are they.... Just listening make me feel good.!!!

[@graxjpg]

Very nice. My headphones are also studio referencing cans, I’m interested in this amp. Thanks for being so thorough and intelligent.

[@MrCarlsonsLab]

Thanks for your kind comment Grant!

[@rickscheck5330]

@Mr Carlsons’s Lab The audio on your videos is sublime.

[@ericgrenier6591]

Excellent video ! I really appreciate the time you spend educating us. All your videos are so interesting. And your english is so intelligible. Thank you so much (a french guy)

[@mattgarcia440]

Great video... The audio quality of your videos has always impressed me...

[@MrCarlsonsLab]

I appreciate that!

[@FiendTheKing]

That would explain why this channel has the best audio I've ever heard on youtube.

[@dashcamandy2242]

3:40 - That power-on "thump" can cause some serious woofer excursion, as I'm sure you're aware. Not exactly what you want expensive studio monitors to suffer from. My first stereo, a 70s Channel Master, beat the snot out of the speakers every time I turned it on. Wasn't long before the speakers were half-blown, thankfully they were free 8" woofers that I mounted in cardboard boxes. (I was an eight-year-old with his first stereo/8-track, don't judge! LOL By the time I had turned 14 I had already spent over $600 in a receiver and cassette deck, my standards had improved somewhat.) While we're speaking of speakers, might I say that the audio of your videos is truly exceptional. My speakers are far from high-end - two Sony bookshelf stereo speakers from 1992, paired with a ported car "full range" speaker box housing a blown MTX 12" subwoofer and a cracked 12" Sony Xplod subwoofer (and MTX-branded midrange drivers with MTX-branded horn tweeters) - but I continue to be blown away in every video at how well you master your audio track. I guess a flat amplifier and a good set of studio speakers really do make a difference! (I use these crappy throwaway speakers in the garage/Man Cave because I don't care what the humidity and temperature does to them.)

[@wthornton7346]

Love the way you marshaled those electrons around. Sterling stuff.

[@xjohnlangerijs527]

Much appreciations m8. Thumbs both up! Namasté.

[@WaterWhiteTuber]

I really enjoy seeing your skills and technique. Thanks for commenting on time estimates for job length, etc. I really enjoy when you do the "this old house" style of program. Thanks for sharing. Would you be able to use a battery backup power supply to protect the system from power sags? Or, would it introduce noise into the system?

[@InXLsisDeo]

Battery power supply doesn't introduce any noise so yes.

[@WaterWhiteTuber]

@@InXLsisDeo Thanks :-)

[@the8bitbarn836]

Beautiful four tube Amp, Awesome 1 db response at the full audio spectrum, nice. As engineers we don't see that kind of care even in higher end equipment most amplifiers we see today there is at least 10 mili-volts of hiss or drive per db. That's quiet like you said and the range 5 Hz all the way to 50 kHz flat lining all the way. I can't say that I can hear frequency that high but I would say that it offers greater harmonic response than anything else out there! Great job great video! Awesome little circuit using a 557 as an off latch timer wouldn't of thought of doing that. When I heard relay I was thinking that you where going to use it to put the monitor speakers in stand by and enable them only if the Amplifier was powered up, remote power inhibit but instead you mute the inputs until the amplifier is full on and active. One concern I would have is would the relay over time distort signal due to oxidation on the contacts? Just thinking long term.

[@jenniferwhitewolf3784]

Been doing circuit design for well over half a century. I only do OTL if I get rid of the capacitors in the output.. I have designed OTL/OCL amplifiers up to 270 watts RMS into 8 ohms, direct coupled, no caps and no transformers, using Wiggins balanced bridging topology, driven by direct coupled differential front end, with mirror image symmetrical active load lines on top, and current sources in the long tails. DC Level shifting is done with high impedance current sources at a negative supply, adjusting the R above it, until correct offset at the node is achieved. Full DC coupling... and it can be servoed if you desire..

[@peterream9437]

Another great lesson, delivered by the best . Thanks Paul.

[@MrCarlsonsLab]

Glad you enjoyed it!

[@kevinedwards801]

Would love to see the artifacts on Patreon. Thanks for the informative and educational videos.

[@smallenginedude71]

excellent video as always mr carlson! Just joined your patreon and for anyone wondering its very much worth it!

[@Thomasp671]

A very nice and clean simple design and its aesthetics are beautiful. Love it !

[@ishimwehonore7436]

Thank you Mr Carlson I really appreciate for sharing this skills skills really appreciate god bless you

[@MrCarlsonsLab]

You are very welcome!

[@Narwaro]

After I watched the intro I immediately thought to use a 555 and a relay to delay the output, but I dismissed that because I thought that you would use some black sorcery magic tricks to solve this, but turns out: very nice and simple!

[@OleF112]

Dear Paul, i watched that nice video with a smile on my face because of the good, old trusty 555, that old guy will live forever. So simple, so useful.. As always thank you for your good job, i know you put a lot of work and love in every single video. 73 de Olaf DK6KF

[@clownhands]

Great video. What’s the purpose of the 22k resistor in the green LED circuit?

[@Dtgr]

I would like to know this as well.

[@nijhuisrb]

I tought the same. There is current flow through the resistor in "0" state of the 555 to VDC6.3. Maybe for even current flow in the system? the green LED takes 2.1 or so voltage off so it is in balance with the red LED turn on signal 0.6 VDC? Far fetched

[@josephmazzeo9413]

Yeah me too I do not understand the purpose of that 22K resister on the green LED circuit. Looks like a voltage divider which will hold the base voltage at about 2 v when 7555 is low. When high it will essentially pull it up to 6v. Should work fine without it?? Sometimes in high speed switching circuits biasing the transistor just below saturation will help shorten delay time but that doesn't seem to be the case here! Other than that the circuit is very straightforward and has many applications!

[@erikdenhouter]

I just set this up to check. If the output of the 555 is NOT connected, the 22k will open the transistor, and that draws 4mA trough the LED, it lights up. Only if you also pull the base with 10k to ground, the LED goes off, as if when the 555 is in low position. The 22k is indeed to aid the saturation of the transistor when it is on. The output of the 555 is always about 1.5V below the Vcc of 6.3V. When you open >in this configuration< the transistor only by the output of the 555, you will never saturate it, because as soon as a C-E current starts to flow, the emitter will rise (voltage drop over LED+R), and you will need more voltage on the base to open it further. Since you cannot reach the full 6.3V on the base (the 555 stays at max. 4.8), it would benefit to add that 22k to full Vcc. But in reality it can be done without it. Only the LED will get some less current than calculated. The resistor is there only for the fact that the LED has been put in the emitter of the BJT. Paul used this configuration with the green LED in the emitter I think because he has 2 coloured LED's with common cathodes. If you use 2 individual LED's you can leave that 22k out, and put the LED+330Ω in the collector of the transistor.

[@erikdenhouter]

@Andrew Hall Sure something like that. The B-E voltage needed is of course always the same (0.6 at first opening), but when the transistor opens, it counteracts that action by raising the emitter voltage, and that puts a stop on the fun. It only opens fully by connecting the base directly to Vcc. The upside of such schematic is it makes a nice regulation possible when you need such. My knowledge lacks a little there. It is where my school was replaced with work.

[@dorjedriftwood2731]

Thank you very much. I’m sorry to say I have absolutely no idea about even the most basic understanding of what I’m looking at but I still find it very interesting.

[@aslerunarborgersen5175]

Hi Mr Carlson, are you a musician too? Do you play and instrument, a guitar or something in a band? I guess you are the kind of man that can be good in almost anything.

[@ResistCircuitResist]

What a well done video. Thanks for the great audio quality. Now I have to go and see if you have a basic electronics theory playlist so I can go an relearn everything.

[@tallperson9422]

Great video! Slowly but surely I'm beginning to understand some of what Mr Carlson is saying.

[@johnparichuk8367]

I haven't heard the term "inductive kick" in a long time. I taught electronics in a Navy school for three years. I would sometimes talk about inductive kick to help explain how inductors work.

[@ag6286]

I'm am ME who's recently began exploring much more deeply into EE over the past year or so. I love audio and have been toying with the idea of a DIY amp. I have high standards. Would love something that can perform like a McIntosh--- keep it coming! 😬 Edit: also, thank you for the basic concepts of electrical devices. I would find EE much more intuitive if people more often explained the fundamental mechanical function of these components and how they all work together. It's been really interesting learning EE -- basically ME but with electricity which is pretty cool!

[@shortstoriesful]

I have gained a great deal of knowledge from your videos. very good explanations om valve and transistors circuits Many thanks Paul

[@greggaieck4808]

Mr Carlson create and Build a electronic circuit is cool my hobbys are painting pictures and lisining to shortwave and ssb iam thinking about getting my ham license I have 4 shortwave receivers and lisn to music

[@josephmazzeo9413]

Great designing on the fly! I like the idea of sketching out circuit ideas on paper first before opening up the CAD software - i sometimes freeze looking at a blank screen but a blank sheet of paper and pencil seems to get me going. This reminds me of a circuit I made years ago to turn off a smoke detector for a 10 minute delay. I made a small perfboard with a 7555 cmos timer (great for low power battery projects!) - fit right inside the smoke detector case. I ran two thin magnet wires to a hidden lever switch to turn it off while cooking to avoid false alarms. Of course, I did not need a relay only a 2N2222.

[@Jedward108]

Amazing that you nailed 30 secs exactly.

[@michaelbishop3701]

Dude, your knowledge is amazing. Thumbs up, my friend.

[@Legoman1976]

Hi Mr Carlson, I'm running out of your videos to watch and not all of us can afford Patreon. Please add more videos here! I love watching your videos and I have got my hands on a 1950s PYE radio that runs on a 90v battery. I found that the variable capacitor was shorting between plates. I have fixed that but I'm glad I started watching your videos because now I know about replacing the paper caps and that they need to go in a certain way around. I also think I'm more confident to do a proper alignment. Luckily, the radio runs on a battery so there's no mains involved. Thank-you for your educational videos, please keep them coming! Dave.

[@timmack2415]

I'm finally coming to terms with your heavy Canadian accent. It took me aboot a dozen videos. I've been stuck at hoome, in my hoose all week, but enjoying your great videos.

[@randalltufts3321]

Excellent video . There is nothing like bueatiful tube sound. Love the project. Very useful

[@Greg-et2dp]

Mr Carlsons lab your utube videos are awesome my friend 🎉🎉🎉🎉🎉🎉🎉😊

[@lwoodt1]

The man is a genius .

[@fmphotooffice5513]

Genius, perhaps. He is a very good engineer. Engineers (n), engineer (v), that is "design new things with acquired knowledge". As soon as you start learning electronics you start getting ideas of what to do with what you're learning. It only gets better as you continue your studies and branch off into a specialty. Very good, well presented KZbin uploads. Hard work pays off.

[@wernerfritsch6436]

The audio quality of your videos is superb as is your pronunciation.

[@harrystevens3885]

What I want to know is how do they manufacture those SMD devices? Fantastic video Mr Carlson just a utter joy to watch,the best of the best on KZbin.

[@VoCodebcv]

Way back when I was learning transistor theory, I remembered the NPN symbol because the arrow is Not Pointing iN.

[@ripsrt6822]

Mr Carlson, I Just made it to the point in the video where you talk about reaction times and your 60' What type of vehicle were you racing?

[@Pawelr98]

There's a simple relay contact delay circuit I use. Just a random tube with 110V or 220V DC coil relay. For 110V the tube has to be triode arranged as current source or sink, with 220V DC coil a tube diode (with resistor in series if needed) is good enough. With so many cheap tubes around it's a nice vintage like solution. My HV power supply uses PCF82. Pentode is error amp while triode switches the relay that limits the heater current for several seconds. As the heater voltage floats around so does the delay, but it also means the other tubes heat up at a different rate.

[@PaulinTaegu]

A simpler design for High Impedance headphones is the DarkVoice. Uses 1 6SN7 and 1 6080, same tubes. 2 triodes in each tube, 1 for each Left and Right channels. I've also made this design using a 6DJ8/6922 for the input triodes instead of the 6SN7. These are a very simple design, easy to build and sound outstanding!

[@redinator9896]

I'm just starting into vacuum tubes. I'm excited to explore the channel. Very nice response 'curve' :)

[@TheoSmith249]

Like any good pilot, you need a Lab audio start sequencing checklist. Thanks for this very interesting video. You audio coming through my Studio speakers is excellent. @32:20 My wife is a palm reader. you will have many more videos in your life.

[@hadireg]

Awesome analysis Paul! 👍❤ Thanks!

[@MrCarlsonsLab]

Glad you liked it!

[@jond1536]

Mr. Carlson, I am sure you have most likely covered this, What is your education in electronics? or What have you done to learn so very much? I am impressed with your very easy manner when you explain things which to me shows a super high knowledge of what your talking about. I am just curious. Thank you for your passing on your easy style and know how.

[@danieljung2810]

This must be said....Mr. Carlson is the Ross of Electrical Engineering. He simply needs to say, "This diode...this diode needs a friend and so will put a resistor to help this diode."

[@davidwhite2011]

Fussy? Certainly not the Mr. Carlson I know!

[@buntykainth3699]

I wish you could be my teacher, your knowledge is unbelievable

[@callmejackaroo4723]

Hey Mr. Carlson, would you consider the possibility of a video series on how to be a badass genius wizard?

[@InXLsisDeo]

Mr Carlson is a complete master at DaveCAD ;-)

[@rdbanks2823]

This was brilliant, thank you!!

[@frankowalker4662]

That was so interesting and informative, Thank you.

[@MrCarlsonsLab]

Glad you enjoyed it!

[@lcarliner]

David W. Berning has designed and patented a design for OTL tube amplifiers that SAFELY obviate the need for any high value output coupling capacitors! These are high powered amplifiers!

[@programorprogrammed]

Great presentation, and as always, learned a lot.

[@tomtke7351]

This delay circuit caught my attention. Specifically, and like some others, I wonder about the 22K resistor in the green LED circuit. When added it was described as "adding drive." This caught my attention as it sounded kludgy. Not knowing the exact LED part number keeps me from being more precise in calculating operating conditions so I'll be limited in "running numbers." The green LED + its current limit resistor voltage drop approaches ~~5V on the transistor emitter The 7555's output, depending upon its current loading is ~6V. Next the 10K resistor in the base leg of the green LED transistor will be dropping the forward bias of the transistor (V-BE) to near or even below 0.7V forward bias required. My choice to assure forward V-BE is strong is to move the current limiting resistor into the collector leg. The potential problem with this is possible excess LED current thru the base. BUT the 10K base resistor eliminates this danger as 10K is ~50x larger than the 220. The filter capacitor around the the base's 10K is 'interesting' too. Described as 'eliminating oscillations' again sounds kludgy. More pragmatically, it seems this circuit was breadboarded and then found to have limitations exhibited as oscillations. The capacitor's implementation appears as a "speed-up" to quickly deliver the 7555's output to the transistor's base which has marginal forward biasing. Again, this narrative is flawed by not knowing.the exact TO-23 LED.

[@Narwaro]

I have to say that your audio has always been excellent, and I use an 18 channel audio interface, seperate preamp and openback Sennheiser headphones. This seems like a very nice project.

[@jamespaterson7597]

very interesting mr carlson thank you

[@vincentrobinette1507]

I would delete the 22kΩ resistor on the base-collector junction of the 2N3904 used to drive the green LED. The reason is, that the output of the 555 doesn't pull down to ground, and, with the drive resistor between the base and the output of the 555, may NOT pull that base down below ~.5 volts necessary for cut off. the green LED may not turn off! You might consider miller capacitance, perhaps a 223 (.022 uF) capacitor between the base-collector junction to prevent oscillation. Remember, the base-emitter voltage decreases, as the temperature increases, and, tube amplifiers get hot!

[@MrCarlsonsLab]

Hi Vincent. This IC being used is not a standard 555, it's the CMOS version. The ICM7555 being used goes "rail to rail," and "does" pull to ground, in this case down to 25mV. As you heat the transistor (green LED driver) externally, the B-E junction voltage goes down, not up, this welcomes the use of the 22K resistor even more. If you are interested is seeing the voltages, and it's affect (the 22K resistor) in and out of circuit, along with scope captures, check out the latest video on Patreon. The circuit is explained in detail with a video. The capacitor is explained with examples as well. Here is a data sheet for you regarding the ICM7555: www.nxp.com/docs/en/data-sheet/ICM7555.pdf

[@vincentrobinette1507]

@@MrCarlsonsLab The resistor would make more sense, if it were between the base and emitter, not base and collector, which makes it a bias resistor, trying to turn the transistor on. However, on second glance, the LED is driven by the emitter, not the collector of the transistor. That means, that you have the full forward voltage drop of the LED, + the drop of the base-emitter junction, so even a standard (NE555) timer IC would be more than sufficient to cut off the green LED. I thought about that, just after I clicked the "reply" Icon. Considering that your supply voltage is ~8.2 volts (assuming 6.3 volts AC rectified with a silicon diode, and filtered with a relatively large capacitor) The coupling resistor needs to be less than 15.2KΩ, for a 22KΩ bias resistor, based on a 1.9 volt cut off, for the green LED. A 10KΩ coupling resistor should be low enough, to pull the LED below ~1.2 volts, plenty low for cut-off. Replacing the resistor with a capacitor, or, connecting a capacitor in series with the resistor would allow the transistor to drop to 0 volts across the LED. I wouldn't change anything now, considering the circuit works. The only value in replacing the 22KΩ resistor with a capacitor is, you can get them both in SMT 0805 size, and can be placed on the same pads on the same board, with no need for a new board. It would only be a minor change in BOM.(bill of materials) Try connecting a volt meter across the cathode and anode of the green LED, and see what it reads, when the green LED is "off". If it's below ~1.2 volts, you're probably OK with the existing design.(I suspect, you will probably read ~1 volt)

[@MegaKid303]

Yes, I suggested a similar project a while ago, exellent

[@PhG1961]

Wonderfull video. I watched it all the way till the end and enjoyed every minute of it. Great job, very well explained and highly entertaining/educational ! Keep it coming... ;-)

[@guidoburgalassi1531]

Sei sempre fantastico in tutti i tuoi filmati, bravissimo!!!

[@GilgaFrank]

Love those big twin triodes, must be great for OTL. I would add that a single red/green dual LED isn't a great idea for a commercial product as it appears as just one colour to people with red-green colorblindness!

[@GEORGE-jf2vz]

Another enjoyable and informative video. Thank you.

[@johnpinner6687]

To mr Carlson,s Lab your video are very interesting

[@MrCarlsonsLab]

Glad you like them John!

[@gpgt1]

Common Mr Carlson, edumacate me! Love the videos!

[@freddiemortos8519]

As always..very clran and neat pcb design..impressive!!!