Building a Tube Amp! Does it produce better audio quality though? EB#47

In this video I will be having a closer look at a commercial vacuum tube amplifier aka a tube amp. I will show you how such vacuum tubes works and how to create a simple class A amplifier with them. At the end I will then show you why some people still like using them even 100 years after their invention, even though they offer lots of disadvantages.

Thanks to Altium for sponsoring this video.

Music:
2011 Lookalike by Bartlebeats
Killing Time, Kevin MacLeod

[manuelminutello]

hi, i would like to point out some inaccuracies....
1 : your " amplifier" has little to do with a tube amplifier since it uses vacuum tubes only as signal buffers, everything coming out of that box is transistor generated.
2 : a true vacuum tube amplifier uses "final" driver tubes to generate the power to drive a speaker, but since they require high voltage as part of their working characteristics they have ust a high impedance output. this impedance is matched with an iron core transformers ( with some special characteristics to improve audio performance ) so in your amplifier you are bypassing about 3/4 of what a tube amplifier really is.
3 : the tube curves are less linear than transistor ones, but you are actually looking at the wrong graph to determinate linearity, audio specific vacuum tubes ( there are RF, IF, oscillator, mixer ecc.... specific tubes) have a grid voltage - plate current graph, si you see the variation of plate current versus grid voltage; this really shows linearity ( remember that tubes are transimpedance amplifier basically )

i also would like to propose an objective osservation, the audio quality can be strumentally measured with audio distorsimeters of fft analyzers ( or a scope fft ) as well as a frequency sweep, if you take a look at some videos by "ElPaso TubeAmps" channel you would see how a real tube amplifier is built and fully tested, a good tube amplifiers does not show distortion of any kind basically, you can achieve even 0.1% total distortion which is a remarkable result.

i do not want to be polemic, i just want to point out some inaccuracies :)
hope you reed this comment!

[LiamsGotThis]

As a tube amp designer, I would like to add on to your theory at the end as you were quite close to hitting the nail on the head. You will notice the curves for the tube not being evenly spaced unlike the transistor in which causes even order harmonics to be generated as opposed to the transistor in which (especially when driven into clipping) generates predominantly odd order harmonics (which sound terrible as they are not musically related notes). The dominant even order harmonic with a triode tube is the 2nd, being the octave. This brings rise to huge popularity using triodes as distortion generators for musical instrument circuits as all distortion generated is musically related to the fundamental frequency and although does contain odd order harmonics, all harmonics after the 2nd decay in even amounts from one another which has the result of the triode distortion not containing too much high frequency fizz! I'd recommend googling the harmonic distribution chart of a triode.

Most electronics channels of course always talk about hi-fi use when it comes to audio circuits but forget that there is a whole other world out there in which distortion is wanted- but you are right in saying that there is a taste for tubes in hi-fi. As I said with the distortion being musically relevent, it can have a nice tone to it. I built my first vacuum tube hi-fi amplifier when I was 18 and I still use it to this day!

[KevinDC]

I wouldn’t be years deep into my electronics addiction if it weren’t for GreatScott! Keep up the amazing work!
-Greetings from Texas! 🤘🏼🤘🏼

[garypaisley]

You have described why tube amps are popular with guitarists - overdriving a tube amp creates much more "pleasant" distortion than a solid state device, rumors have it because of the addition of even as opposed to odd harmonics, something you could easily verify, or not. Great episode!

[tfr]

The way the camera focused perfectly on the "Hi there" made me smile

[gabrielmachado]

So, read this from Brazil: we love you and your work! Keep going, there is only success in your Future!

[kevgermany]

Curves. Always good! And a tube amp in winter helps with heating.
Overdriven valves for rock guitar!

[gustavs]

I've been watching you for almost 6 years, and you're the best electronics teacher I've had. Your videos never fail to teach me something new, keep up the great work!

[rosettenzerrer]

As mentioned below, an amp is not a tube amp because it has one single tube in it. Building a tube amp from scratch is a tedious task involving much planning, calculating and reading datasheets, while dealing with lethal voltages. I built a lot of real tube amps and i repair and service them regularly. Tube amps are fascinating and great fun and every visitor to my house likes the sound of my stereo or guitar amps.

[Toxicity]

We asked espechally in your "electrically generated music" Video, because overdriven tube amps are used for the typical rock and metal sound.
So a lot of musicians use Tube Amps for their sound.

[luizdanielsantos]

I had a grandfather who worked with TVs based on tubes, back in the old days.. He loved when transistors went to market, as they get rid of many problems tubes had: high voltage, excess heat, fragility... Anyway, nice videos! Keep on with such great content.

[liam]

I'd like to see you do an AC sweep for audio frequencies and do a Fourier analysis to see if the difference in sound quality has anything to do with the frequency response of the two amplifiers. Maybe even create bode plots for them and compare.

[alaricpaley]

As a little tidbit - Part of the distortion characteristic of tubeamps is that instead of clipping, they tend to compress the signal instead. This gives a much more tolerable sound when you begin to get any distortion, and can squash some of the highs downwards, giving that 'warm' sound.

[magicmulder]

Many audiophiles love that soft distortion and imperfection, that’s why both tube amplifiers and vinyl records are still a thing.

[abysspegasusgaming]

Having owned a tube radio (1950's RCA Victor), it really is night and day between tube and transistor/ic. Listening to the audio as it faded in was something too, unless the tubes were warmed up already.

[AfterMarketGaming]

Posted 2 mins ago and already 27 comments and 200 views. You have an ACTIVE community! On a side note, BUILD IDEA: automated aquarium ecosystem w/ sensors

[Immanuelf]

I've used to play guitar as my hobby for the past eight years. I'm really happy for this video and thanks a lot for you hard work and dedication. Looking forward for the upcoming videos.

[matiasdg]

Mr. Carlson: "Hold my oscilloscope"

[Asu]

You read a lot of comments everyday, make sure this is one of them.

[jaa]

I think greatScott needs to have a chat with Mr. Carlson.