VALVE/TUBE Amp Circuits EXPLAINED! | Too Afraid To Ask

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Valve amplifiers are still the most desirable sound in guitar music despite the vacuum tube being made obsolete by transistors in the 60s.
What is going on inside to make them still sound so good all these years later?
We analyse the circuit of the Orange AD30 to find out more.
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AD30 Gain Appreciation:
• Orange AD30 - Class A ...
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Опубликовано:

17 май 2024

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Комментарии : 308

@ScienceofLoud 2 года назад

@doctorscoot 2 года назад

in my memory, if it has push pull then it's class AB. a strict class A would have a single amplifier stage (one output valve) and then removal of the DC bias via the output transformer

@ScienceofLoud 2 года назад

Class A push pull is also possible as described in this video. What you are thinking of is Single Ended operation which can only be Class A

@doctorscoot 2 года назад

@@ScienceofLoud ahh yes ok. I was taught in a naval workshop but it was goddamn years ago now - thanks ;)

@davidfuller581 2 года назад

I think it would have been prudent to mention that a gain stage with grid input and plate output has an inverted output polarity compared to the input, which is part of how the phase inverter/phase splitter works. (This amp's phase inverter is a kind of circuit is called a Long Tail Pair or Williamson inverter, but I'm sure you know that). Otherwise kudos on a good basics video.

@okayestguitar66 2 года назад

Your simplified description of class A vs AB is, in my opinion, one of the best and easiest to understand. Thanks for that. On a side note, do you record to tape? Or was that just for show?

@achannel1818 2 года назад

Mad respect for teaching some real engineering here.

@mihailmilev9909 Год назад

90th like

@steveg.3022 Год назад

I learned this in electronic tech school back in the ‘70s. Great to see this here.

@johnegginton 2 года назад

Possibly the best PSA I've ever heard! "I'm not responsible for any electric shocks, injuries or deaths that result from the stupidity of you ignoring this warning" 😂 On another note, brilliant explanations! This kind of thing is something I really enjoy learning. I've been building pedals for a bit now and have a background in electrical and electronic engineering. I don't have any valve amps to tinker with though so I'll not die just yet 😂

@mihailmilev9909 Год назад

Same! Ikr lol. Loved that

@Geopholus Год назад

i've been tinkering with tube based amps for almost 60 years since before age 12, with the amount of caution that a reasonably mature 12 year old can muster. Though I appreciate the warning, one can go too far with such things, and not describe how to be careful (which one should) in such a video), and not encourage people to try things at home,... no one really learns anything except through experience.

@Ten80pete Год назад

Can confirm that the old tube electronics pack a hell of a punch. I only wish my Dad or brother had given me this warning when they were fixing an old floorstanding radio model when I was 5. It was off and unplugged, but don't expect a little kid to NOT touch something that has that warm glow.

@hazrod13 2 года назад

One more perfect TATA video that I'll be re watching many times !

@Tehstroyer 2 года назад

Me too. Maybe I'll even understand it one of these times.

@armax00 2 года назад

with all these diagrams and wonderful explanations, I am still waiting hopefully to purchase some day the guitar related electronics course :)

@ScienceofLoud 2 года назад

If I ever take a break from weekly videos here on YT then I'll have the time to make it happen.

@mihailmilev9909 Год назад

Lol

@mihailmilev9909 Год назад

Lul

@PJ-hn4cg 11 месяцев назад

Ha ! Yep !

@admnovsk88 20 дней назад

This brings me back to analog circuit class back in college in 2006, thank you

@kevinhernandez2594 2 года назад

Therapist: Southern Colin isn't real and cannot hurt you. Southern Colin: 18:03

@glassappreciation8883 Год назад

Such an underrated series, couldn’t ask for more.

@ikestoddard2458 2 года назад

Colin, this is a marvelous explanation. I am an electrical engineer but just into the transistor era of training. I think you covered it well. Thanks!

@attilacsaba 2 года назад

its not like im going to go and build an amp but this was interesting and good to know ... thanx

@yoshi-808 2 года назад

That was a two-sentence masterclass in impedence matching!

@mingram008 2 года назад

Excellent job explaining the sections of the amp! It was very easy to follow AND made sense! Keep these videos coming and we DO appreciate the work you put into them! Will be following.

@Jesterhead21 2 года назад

This channel is pure gold. Thanks a lot mate!

@jamessilver2748 2 года назад

Brilliant vid, I learned a lot there Colin. The "too afraid to ask" series has been inspired.

@hankgesmag9650 2 года назад

From one scientist (MSEE) to another (Colin): Nice presentation! Probably one of the best on RU-vid...

@beaarthurmiller 2 года назад

Discord notification squad!

@hazrod13 2 года назад

Squaddddd

@ScienceofLoud 2 года назад

SQUAD!!

@dc4019 2 года назад

SQUAD

@kirkbolas4985 2 года назад

Le squad

@NashTheGreat 2 года назад

Сквад!

@StratsRUs 2 года назад

Your perfect presentation and pacing takes you beyond just the guitar world.You make a great teacher that expresses themselves because you are a musician too.Amazing work.Thank you.

@WwYnN 2 года назад

I like your explanations. Not boring, not over complicated. Well done sir.

@paulzytsel3557 Год назад

WELL DONE - FROM A TECH WITH OVER 40 YEARS EXPERIENCE.

@koyzumie 2 года назад

Excellent explination and great visuals! Thanks for making this 🎉

@dc4019 2 года назад

I absolutely adored this video! Thank you!

@Christopherjazzcat 2 года назад

Great sounding amp and informative video. Thanks for all you do mate.

@pooshNchums 2 года назад

This is amazingly informative. Thanks Colin!

@justincary1599 Год назад

Such well presented, accurate information. Subscribed!

@shaunoleary8740 10 месяцев назад

That was such an excellent explanation, thank you!!!

@Spivonious Месяц назад

Fantastic! This really helped me understand the schematic for my Genz Benz El Diablo 60 and identify the various pieces of the circuit.

@silasfatchett7380 7 месяцев назад

Another clue that the AD30 operates in Class AB is the sag when digging deep. While all the output tubes are conducting, the current draw from the rectifier is constant, but increases when two valves are cut off, so there would be no sag if the amp were true Class A.

@mrgunn2726 Год назад

Great presentation, thank you so much!

@yogi9631 Год назад

One of the best explanations 👍👍

@bigwavedave8492 2 года назад

Your the best thanks for sharing the knowledge

@andrecepeda1 2 года назад

What an incredible video! Congrats!

@nurk_barry 2 года назад

I’ve been watching some real in-depth videos over the last year or so about how tube amps and transistor amps work, and it’s so cool to see this channel go so in-depth on the circuitry. Apparently Colin has some engineering knowledge.

@ChrisBlackLabel90 2 года назад

Just watched this after a 12 hour shift; my brain hurts now. Thanks Colin.

@rydinorwin Год назад

Fantastic vid man, many thanks!

@timburle4980 Год назад

Great explanation!

@richardmawdsley2589 Год назад

Great explanation, thankyou. I still use my Fender Bassman 135 silver face for regular gigging on bass!

@trevorjohnson8142 Год назад

Thank you so much; this video is perfect!

@rotaxtwin 2 года назад

Brilliant, your addendum to go into detail on Class A, B AB was very good.

@fink94 2 года назад

Great content!!! I just can't get over how much I LOVE your accent!

@johnrodgelatenemusic7262 2 года назад

This has to be one of the very best explanations of how valve amps work that I’ve seen in over fifty years of working with the damn things! Loving your channel Colin.

@vincentl.9469 2 года назад

All well & good but will this stop valve amps ending up on the scrap heap?

@johnrodgelatenemusic7262 2 года назад

@@vincentl.9469 mine certainly won’t. But I’ve got a few spare sets of valves which will see me out. Long term I don’t know, maybe you’re right.

@leventejordan8355 29 дней назад

16:45 Starlight - Slash, Myles Kennedy

@MrGibsn1960 9 месяцев назад

This video is perfect.

@emmettyoung7603 2 года назад

i don’t play metal, but i love your channel a ton. it’s useful for everyone who’s interested in music or audio.

@matiaslopezvarela926 2 года назад

Love that laphroaig 10 next to you. Valvs and Single malt 🙌🏻

@joedebono4012 2 года назад

Great video very informative

@johnmac8084 2 года назад

Great explanation, liked & subscribed, thanks

@nairanvac79 2 года назад

Thumbs up for the Laphroaig 👍

@Lukas_Hart 2 года назад

Nice explanation! Very interesting and understandable, well done. :)

@AlbusBand 2 года назад

Well said my dude….I love the science behind why things work the way they do; even if I have to re-watch to digest it all. You sir, are second to none. Hope you’re well.

@tacos666 2 года назад

Really really interesting topic ! I learned a lot, next video, more in depth on each part of the circuit component wise ;) I want to create one now ^^ Thanks a lot for all these informations !!!

@jcool0122 2 года назад

I build amps as a hobby and I have to say that is a very clear and concise explanation. Can you do that with the switching section of a Boogie?

@jcool0122 2 года назад

@@dr.know-it-all5148 actually, Brad the Guitalogist is the only person I've seen on RU-vid take on a Boogie.

@knowmusicman157 2 года назад

@@jcool0122 he's qualified

@castleanthrax1833 2 года назад

@@knowmusicman157 He's also nuts. ✌️🇦🇺

@lucaszembrzuski 2 года назад

Thank You dude, very informative and interesting :)

@TyroneNorthcutt Год назад

I wonder how many people just skipped to 3:55.... 😛 Love what you do brother, thank you for all the great info over the years.

@KRAZEEIZATION Год назад

I’ve been using tube amps since 1994 and nothing else can match the sound and touch sensitivity. Now I’ve 6 tube amps amps and have no issues with owning many more!

@saarangnarayan123 2 года назад

Thanks for this! I have so much to talk about at parties now!

@Paul_Lenard_Ewing 2 года назад

Excellent, Excellent, Excellent!!!! I would love to see a series of shows breaking it down into smaller chunks so you can use more layman's terms in your description. Things like what's a diode need clarity. It is like explaining how a house is built and using the words brick and bricks when one does not know what a brick is. This does give one a good overview in a short time so it serves it's purpose. In short one gets the big picture here. For example I like to start with the A/B thing with the idea it is a bit like a old fashion hand pump to pull up water from the ground.

@theroadsnearyou...5088 2 года назад

Fantastic video!😁👍

@creationinspired200 Год назад

Thank you sir 🙏

@parkerdavidson5868 Год назад

Working on my amp like a cheap dum dum instead of taking it to a repair technician. I did once before and it actually worked out, but my job was minimal and just enough to keep the amp running, so I'm gonna go back in soon and redo it properly. I'm on a kick of researching more how amplifiers work, and how to safely work on them, and it's an absolute win that the example you have today is my amp! Thanks for this video!

@grberendzenproductions312 2 года назад

Very thorough! I wanted to watch just to see how well you'd explain things. (Plus, I like it when you say "zed") I'm impressed! You went through phase splitting and impedance matching as well. The only thing you didn't do was explain how to drain a capacitor so you could safely handle it, but you weren't teaching how to work on an amp, just how they work. And you let us know never to turn on a tube (or valve) amp without a load. Well done!

@castleanthrax1833 2 года назад

When I bought my first valve amp (many) years ago, pre-internet, I didn't know anything about them but I kinda guessed the importance of attaching a speaker, going by the bright red indicators around their input jack sockets. ✌️🇦🇺

@silasfatchett7380 7 месяцев назад

Turning on a tube amp with no load is not a problem. Attempting to amplify a signal with no load causes damage.

@user-io8vk4ep3j 9 месяцев назад

Colin, your videos and succinct explanations of these various topics are brilliant. I’m probably not the first to ask, but have you done any content on “valvestate” amps? Or would you? I own a Marshall AVT150 that I acquired years ago and played it for a little while before moving in the direction of Fender tube amps. I like the idea of acquiring another Marshall but I’d like to explore what that AVT150 can/can’t do first. Anyone’s thoughts are appreciated! Thanks

@mattheweady615 Год назад

Can I ask what camera you use for your videos? They are very high quality :) Great content by the way

@williambock1821 2 года назад

That was the best explanation of what true class A vs AB are I’ve heard yet! Very nice! It DOES get confusing when you see amps calling themselves class A that have more than one output tube. If you REALLY want some sag, stick a 5y3 in there! A GZ34 is extremely close to SS diode performance.

@danielrose542 2 года назад

Very very good job!

@marinosvafeiadis2655 2 года назад

Great video! However please explain how you managed to connect the reverb/delay rack since there is no fx loop on this amp!

@felinekaiju4517 7 месяцев назад

I'll have to watch this a few times to understand what I need to. I'd also like to make a dual rectification set up like the road king so that Valve rectifiers for clean and edgebof breakup tones and diode rectification for crunch and distortion.

@acook213 4 месяца назад

Thank you, Scottish Macauly Culkin!

@Merjia 2 года назад

It's saturday night, I've got my dram of Laphroaig, lets go!

@MindsDozer 2 года назад

i've got pretty strong comprehension skills and this stuff flew right past me. is there any prerequisite material you can recommend so that I can digest what looks like it would have been a very interesting video?

@emptyMan0 2 года назад

Thanks for the video, Colin, it has cleared some of the mysteries, but some still remain. Could you possibly elaborate in a future video on some of these topics? - If I have a multistage preamp, does the gain knob actually turn multiple potentiometers, one for each stage? - What is a valve bias? - How can a valve amplify in the negative portion of the wave if it only allows current to flow in one direction?

@silasfatchett7380 7 месяцев назад

In an amp with an input stage followed by two gain stages, a single gain control is positioned before the 1st gain stage, controlling the amount of signal which goes to the 1st stage from the input stage. As the gain control is advanced from zero, at first both gain stages amplify cleanly, then as it is advanced further, the amplified output from the 1st stage overdrives the 2nd stage clipping the signal resulting in distortion. Eventually, the increased input from the input stage to the 1st stage overdrives the 1st tube adding more distortion. At maximum gain, both tubes are heavily overdriven for maximum distortion. When no signal at the grid, there is a current flowing in the tube, so that a positive going signal on the grid can increase the flow, while a negative going signal can decrease the flow. To accomplish this, with no signal at the grid it must be at a negative voltage with respect to the cathode which is known as 'negative bias' 'Biasing' is the process of determining the negative bias voltage during the design of the amp. It can also mean adjusting the negative bias on output tubes, which in turn, controls plate dissipation.

@emptyMan0 7 месяцев назад

@@silasfatchett7380 Thank you very much! The gain control now makes sense to me. I am still not sure I understand the bias thing. Does it mean that the amp is set in such a way that the plate is the input voltage plus a constant voltage roughly in the middle between the cathode and anode and that is then somehow subtracted before it hits the speaker?

@silasfatchett7380 7 месяцев назад

@@emptyMan0 At idle, the plate current in the tube flows from the plate through the plate resistor to the positive supply, so according to Ohm’s Law there must be a voltage dropped across it. This means that the supply voltage is shared between the tube and the resistor. The negative bias voltage is set so that the plate voltage at idle is at around 2/3 of the supply voltage. A signal on the grid varies the plate current which varies the voltage across the resistor so that the plate voltage varies in sympathy with the grid voltage, resulting in a much larger (and inverted) copy of the grid signal at the plate. This varying voltage is fed to a coupling capacitor which blocks the DC idle voltage but allows the AC signal to go to the next stage.

@emptyMan0 7 месяцев назад

@@silasfatchett7380 Thank you again, I think I get it now.

@Yupppi 2 года назад

This is the good basics stuff that is still difficult to find unless you browse through forums and it's almost never as coherently explained. Even the literature is a bit here and there and not necessarily available anymore. Very good episode. Does the single half of a triode invert the signal btw? In the graphics it was still in the same phase, but how does the blocking of the grid actually affect the electron flow? Does it depend on other features if the valve inverts the phase? I also sometimes see techs preferring to bias for slight crossover distortion, which to me is very interesting when many times you see people talk about crossover distortion as something you absolutely don't want. I understand that most of the time if the amp is rated much above 5 W, you can be almost sure it's class A/B instead of A, that it would become so costly to amplify with more power in A. Any thoughts on the common ranges of class A? And like you said, probably the first part of the amplification is in A often times.

@MagyHimself 2 года назад

Yes, the triode inverts the signal (when its provided through the grid), if taken from the anode. When taken from the cathode, it keeps the original phase.

@Geopholus Год назад

Yes, the signal is inverted relative to the input control grid signal, by a common plate circuit, in which the output is taken at the plate resistor ( higher value or equal to the cathode resistor ). Magy Himself, is correct,.. although in the case of the phase inverter, the bottom half of the circuit , which is called a "differential pair", produces a non inverted output signal relative to the top signal grid because it's grid is referred to ground, but the sum of the two currents at the cathodes (where they join together is a point of unity (no signal)), so the grid of the lower part of the differential pair receives a degenerative feedback signal at it's grid which, is out of phase with the signal applied to the top grid. I know that sounds confusing, but that is how it works. The bottom half of the circuit receives a "virtual" signal at it's grid because the two currents sum together to equal a constant current, at the cathodes.

@silasfatchett7380 7 месяцев назад

The varying current (electron flow) flows in a plate resistor to the positive supply. At idl

@silasfatchett7380 7 месяцев назад

Sorry, changed my mind. I remembered that I posted an explanation elsewhere in these comments, then hit the wrong button.

@alexcorona 10 месяцев назад

It was well before the 60s, I have a solit state amp from the 50s and it sounds fantastic. Germanium transistors an all. Just had to replace the caps that went bad. Other than that shes a beauty.

@sgtcaco 2 года назад

Can you please do a in depth tutorial on plugging the power cable on. Thanks, made respect

@DesertRat332 Год назад

Explained so well, even an old mechanical engineer can understand it! 😄 I'm still glad I didn't go into electrical engineering, because that stuff is a magical black art!

@OsLapsosBandaRock Год назад

Valve Amps are the electric guitar best friends!🤘🤩 Great video, by the way!

@aspeguitars4071 Год назад

Nice amp, great distortion tone. The added digital(?) reverbish effect however takes the tone down. Thanks for your pretty well made video.

@JuveriSetila 2 года назад

O hai. This is a great comment left for this great video on this great channel, and my great plan is just to make the algorithm happy. Great!

@frankdstrack Год назад

I would love to see one of these on how attenuators work. 🤘😫

@matydavus1078 2 года назад

Awesome

@calyodelphi124 2 года назад

That phase splitter circuit at 8:30 is a long-tailed pair in vacuum tube form! :D en.wikipedia.org/wiki/Differential_amplifier#Long-tailed_pair

@IanHaghighat 2 года назад

I was hoping there would be AD30 content!

@jerryjones698 2 года назад

Where did you learn all of this?being able to work on your amp is valuable knowledge

@Mikey__R 2 года назад

A fun way to find out if a valve output stage is actually push pull Class A, is if the shared cathode resistor is missing its bypass cap. In a true Class A amp, the current signals through each valve will cancel, so you'll get no AC component superimposed on the DC bias voltage, so the amp would be unable to operate in Class B. If you do have bypass caps, which are necessary if you dont have shared cathode resistors, then it /might/ be Class A at all output levels, but it'll probably start to push it's way into Class B as the stage begins to saturate. You're right, it's all marketing, and TBH I think most people think Class A means cathode biased EL84s, no matter what the actual class of the amp really is. Final point: cathode based amps actually have worse crossover distortion the deeper into Class B they go. It's not a bad thing, it's part of the sound and bloom of the amp.

@BrandochGarage Год назад

Love your channel. Took me 50 years to figure out what high tension meant. And I learned it from a guitar Channel. You gotta have the valves if you want to be haired. Peace.

@fatpad00 2 года назад

TATA- is there any difference between tube/valve amps and transistor amps besides the component doing the amplifying? I have a surface level understanding of transistors from some classes almost a decade ago, and all that low power contro circuits

@AxelHavoc 11 месяцев назад

I'm looking into making my own tube amp. My solid state fender champion 100 made magic smoke. So I may put a tube amp in place of the solid state circuits. Since i have an empty cabinet now

@Talmie 2 года назад

You may be rich in knowledge, but i have Laphroaig 30. Great video!

@jessebreakspear6656 Год назад

That was awesome! now I understand the class A vs class AB concept so much better. I still don't fully understand how the myth of the Vox AC30 being class A got started but that would be more of a history lesson right?

@effsixteenblock50 Год назад

I'm not sure but perhaps AC30s are biased in such as way as to spend most of their time in class A. They certainly sound more class A than your typical Fender or Marshall amp.

@kdawgtv1333 Месяц назад

Had no idea what the hell you said. Damn electronics are like magic to me 🥸

@fretout Год назад

11:15 - or, you and have the best of both worlds at the same time with Simul-Class!

@rileyioacura 2 года назад

RU-vid seemed to have unsubscribed me which I didn’t know.. so I’ve subscribed again

@stayoutoftheswamps Год назад

Suggested TATA, how does channel jumping work and how do different 4-input amp circuits compare?

@hadleymanmusic 2 года назад

Man on my crate tv 6210( used) I lost all the tubes and the pilot light. The amp comes on the trans warm up the led channel switches and lights up but not a tube heats up. Is the pilot light in series with the tubes?

@nomadenview 2 года назад

Sorry ,,,can I know what kind camera that you use? Thanks before

@Eswald Год назад

Awesome video, very informative! A stupid question from someone just getting into guitar tech: I presume both arrays of EQ knobs equalise the respective channels, but if I saw the schematic correctly, the volume knobs are for each phase after the phase splitter. Does that mean that the volume is dialed in for both channels at the same time?

@ScienceofLoud Год назад

Each master volume is dedicated to its respective channel - after the phase splitters as you note - but the volume controls are dual gang potentiometers, this allows for synchronised volume adjustment of both split hemicycles. This arrangement is duplicated for both channels: if you look at the schematic again you'll see that there are two almost identical, independent signal paths from input, which only converge again at the power valves - AFTER both of the volume controls. Mast1 & Mast 2 are both the same potentiometer for Channel 1, Mast3 & Mast4 are both the same potentiometer for Channel 2. This is to say that each channel as completely independent gain, EQ and master volume controls.

@Eswald Год назад

@@ScienceofLoud Ah, yes I see, makes sense now! Thanks for the response. Really liking your content, keep it going!

@samuelxavier2473 2 года назад

Good stuff, as always. Would love to split a bottle or two with yer.

@ForTiorIJohnny 2 года назад

great video. here´s a follow up TATA - what makes two different amps sound different even though they use the same tubes?

@ScienceofLoud 2 года назад

The rest of the amp

@MrMshossain 2 года назад

@@ScienceofLoud then could you do more videos on why these amps sound the way they sound aka the rest of the amp. Like what makes a vox sound like vox or marshall stuff like that

@TheCrimsonIdol987 2 года назад

Colin said it right, it's the rest of the amp. When a designer is making a guitar amp circuit, they're carefully considering things like resistors, capacitors, potentiometers, and such within a certain tolerance for two reasons: 1. So the signal gets amplified. 2. For tonal reasons. As such, they consider vacuum tubes a mere component that falls within the parameters they want for their circuit design. These different parameters, tolerances, components, as well as the design of the circuit itself is what makes these amps unique. This is why, say, an Orange Rockerverb sounds different from a Mesa/Boogie Dual Rectifier, beyond the tubes they're using.

@AlexdeLarge6655321 2 года назад

Hi Colin! I have a Vox VR30 hybrid amp. The manual is like a timeline of Nigel Farage tweets: it contradicts itself a lot. One part says the pre-amp is valves, while another says it's the power section that utilises the tasty tubes. I've never worried about it, because it sounds great, and just recently got me told off for 'coming in like an earthquake' when I insisted I didn't need to go through a mixing desk and could control my own levels in the local church, which I was suitably chuffed about. "Forgive me Father, for I have strummed."