Discrete audio amplifier project PART 2

[@boonedockjourneyman7979]

Fantastic. After nearly 40 years of teaching grad students, you humble me. The figure with various theoretical IV relationships next to circuit elements directly (and functionally) impacted is something I’m going to steal. Really nice work.

[@andymouse]

4 years have passed I'm concluding my board design soon and I just wanted to watch it all again as my knowledge has improved or rather improving ! my interest in amplifiers comes from a love of music, electronics and your project so another thanks from me !....cheers.

[@JohnAudioTech]

Same with me. Music and electronics!

[@stevenstewart5980]

I'm so glad you are moving forward with this project John. It's great to see all of the things that should be considered in the design. You really know your stuff. Also, I'm glad that you now have a Patreon account. I'm signing up!

[@linorocchi9339]

I'm waiting for the next video. Thanks.

[@stuartmp1974]

Nice work John

[@snaprollinpitts]

John I have to say "it is about time", many of us want to help you, and this is a great way to do just that!!! a patreon subscriber.

[@peteb2]

Excellent beginning John and i learned something as to the 1st step in designing such a circuit. I also have to say Mr Whiskers will have his own fan club soon!

[@MarkTillotson]

Excellent start to the series John, nice clear discussion of output device power dissipation - I like the approach of choosing high voltage devices where the secondary breakdown hardly kicks in at all at the voltages for this project. Secondary breakdown is, I suspect, a major reason for amplifier failure in the field.

[@Tbonyandsteak]

Your choices make it sooo interresting project, totally agree with it. Keep the options open and make the foundation solid.

[@seanhopta]

I appreciate you taking the time to make this video.

[@1959Berre]

Outstanding! Can't wait to see the rest of the series.

[@johnsenchakinternetnetwork2025]

AC Peak - VRMS x 1.4.14 Mr Whiskers is telling you his hungry Why not use high powered MOSFETS instead of transistors on the output stage This was a real nice video

[@abdullaalmosalami]

13:45 Note here! Common mistake! Inducive loads of course do have lagging current, BUT if you put that up to a scope, what you'd see is the current wave form IN FRONT of the voltage one, not behind it. If a sine wave X leads sine wave Y, X reaches its peak BEFORE Y, so on a scope or on a graph, it looks as if X is behind Y PHYSICALLY (i.e., to the left), but we call X leading Y in phase!! Just something that I remember confused the hell out of me when I was in Circuits 2. And of course, likewise with a capacitive load, the current waveform leads the voltage one, so you'd see the voltage waveform be in FRONT of the current one physically, but it is lagging in phase. Kind of confusing but very important to know so you don't spread the confusion even more!

[@n.shiina8798]

i like this series! reminds me the first time i learn the basics like 5 years ago.

[@Gersberms]

John, these videos are great, I love that you are putting your expertise into a design for people to use. I'm glad you set up Patreon, it seems to work for other channels. Have you thought of including affiliate links in your description and videos? This is something that's common now, and makes a lot of sense when doing reviews.

[@joohop]

You Are The Man ! My Little Dog Alfie's Ears Pricked Up When He Heard Snicker's ! !

[@fernandocoelhopt]

Mr John at his best....

[@cafe80s]

I can't wait to buy this! It's going to be so much fun!

[@eggshellskullrule7971]

Thank u so so much, John!

[@bixy9347]

Great work John, very good so far, Thankyou 👍

[@spark300c]

protection circuit? isn't why capacitors are use to prevent dc form going to the speakers. for audio power should be bass on square waves because it so close to 100 percent unlike a sine wave.

[@carltonr3417]

Awesome! Great stuff! Just wondering if you could add a clipping LED to the design? That's something I've always wanted when playing music loud.

[@christophschuermann6512]

Carlton R I agree, a clip indicator helps to protect your tweeters. The same is true for a good input-limiter to prevent hard amp-clipping.

[@JulioGutiérrezdiaz]

buenos video gracias por sus lecciones esperando con ilusion el siguiente video

[@decaelo.decidit]

I Love that cat hahaha great video 👍🏻👍🏻👍🏻

[@JonathanGerardDias]

Hey John i've been building a power supply 33.4 - 32.6 regulated on the rails for a studio monitor setup (which again im desiging) i intend on starting an audio electronics company hence the research and development along with the fire now and then. so if anyone wants a really dope power supply schematic reply to this comment. Also using a TIP35C 80Volts 25Amps. using the 70Volts rail it'd be perfect i think.

[@abdullaalmosalami]

Also, in your Vrms and Irms calculations, you used R = 8ohms, but these calculations are for purely resistance loads, and the 8ohms is accounting for reactive impedance. In fact, it is the impedance at some particular frequency. If you look at the datasheet for speakers, they have an impedance with respect to frequency curve that starts low (i.e., DC), then rises to some peak ("speaker resonant frequency"), then goes low and flat for a range of frequencies, then starts rising again. As an example, here is an SDS Subwoofer www.loudspeakerdatabase.com/Peerless/SDS-P830657. All in all, the impedance of the speaker varies with frequency, and that changes the complex power it is consuming. For the requirements of the voltage rails, going from the wattage rating, that is the real part of the complex power being supplied, and so you only use the resistance component of the impedance. So R should be 6ohm in these calculations if I'm not wrong, ignoring the AC skin effect of course. It's not a huge difference but I just wanted to point out that detail.

[@Brant_Channel]

Great content. Thanks for sharing!

[@manimanipal1818]

Very good explanation

[@electronicssciencebysherry5050]

Good work John thank u

[@boonedockjourneyman7979]

If you do your best at this stage, people like me that specialize in linear supplies can cover that. Protection circuits are another specialized area. Preamps, man I don’t know. Maybe you. Stay focused for now. Bring in helpers as you get there.

[@jimhough6233]

60V, 15A, 115W

[@jimhough6233]

ON Semi is still making 3055 and 2955.

[@jimhough6233]

Go John! MOSFET outputs?

[@goglu2]

lateral MOSFET ECX10P20 and ECX10N20 from Exicon (ProFusion) ;)

[@charlesklein7232]

does it make a difference weather or not i use the correct "ohm." i see very small 4 ohm speakers but my amp uses 8 ohm. im only 4 feet from my tv so i dont need volume and i have been told that 4 ohm is better then 8 ohm and so the quality would be better?

[@elio965]

Thanks for the video.

[@fiftytwogaming.8621]

i watched a video on your channel about finding the resonant frequency what amplifier do you need for that?

[@EngineeringEssentials]

From the design point of view I got the feeling that one pair of 2sc5200 with 2SA1943 can only output around 100w rms at it's best. Is it so? Or I put a lot of safety margin in this situation.?

[@JohnAudioTech]

I'd say that is correct for lower impedance loads, such as 100w into 4 ohms. Peak current is 7 amps for a resistive load and there is some margin for reactive loads.

[@HillsWorkbench]

BTW Patreon has bought up Kit.com

[@rogerfurer2273]

Check out On Semi MJ15024 devices for higher power rating.

[@tobias56375]

Maybe take a look at douglas self "power amplifier design" i found it for free by a bit of reserch. Its a really nice book about amplifier.

[@JohnAudioTech]

I got that book through an inter library loan a couple years ago. Only had for a week, but it is a good book.

[@luisgasca9707]

Awesome video. I had a question for why you said a peak of 7A for the 4 ohm load. I get we are cutting the resistance by half, since current is squared, it only needs to grow by sqrt(2) for the same power. So I I got a peak current of 5A. I think I may be missing something

[@JohnAudioTech]

When you half the resistance, the power is doubled in the load given the same voltage, therefore, you must use 100 watts in the equation shown when the resistance is 4 ohms.

[@ats89117]

Because of the non-unity power factor seen by the drive transistors, you will need a higher voltage rail to really achieve 50 Watts of power dissipation in a non-resistive load. I doubt your 4 Volt fudge factor will be sufficient...

[@ADRIANNORMANNINA]

Keep it up!

[@scottmuckleston3308]

What about using the 2SC2922, 2SA1216 or MJL3281A, MJL1302A or MJL4281A, MJL4302A on your amplifier project?. I have design a class d amplifier on the TPA3118, TPA3116, TPA3130D2 with through hole components. I have the PCBs made by JLCPCB (JLCPCB.com).

[@Detailverliebt]

I would like to buy one - will you ship internationally (Europe)?

[@JohnAudioTech]

I will look at the costs. I would like to make them available to most locations world wide.

[@Detailverliebt]

@@JohnAudioTech do you have a schedule already?

[@JohnAudioTech]

@@Detailverliebt Not yet. I don't have a finished design.

[@RobertKohut]

Nice!!

[@avesbilal]

Thanks for the awesome video, will appreciate if can also design a nice power supply schematic, people can easily replicate it on breadboard. As I believe a good designed power supply is necessary for a great sounding amplifier. A CRC power supply is good if I am correct but I'm not smart enough to design it myself.

[@jimhough6233]

Much better As our there though

[@nitescuvalentin6872]

Too bad I ordered a LM 4780 tube buffered board from Jim's Audio already

[@MrTheDarku]

No down votes... Weird for KZbin

[@christopherkise]

meow

[@jimhough6233]

SA. Yeah! 3055 2955

[@brianksiazek767]

I'm First!!