Building a class A audio amplifier - no audio out

Buy this. It's ANCIENT and refers to a lot of obsolete op-amps which with intelligence you can substitute with better modern parts but it covers some good ground like noise calculations for example. It helps you get the feel.

I have an original print copy of course. Finally it''s been reprinted.

TI have some super and huge IC mainly handbooks too that you should have. I'll need to recheck their filenames.

Graham

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How could you be offered a job in C programming if you didn't know C programming? (thoroughly confused) That would never fly over here.

On that note... I took a biochemistry lab class where I had to calculate the A, C, G and T fractions from DNA analysis of a bacterium. It involved *a lot* of punching numbers into a calculator. I thought, "screw this" and wrote a Pascal program to do it. I turned in the source code with my lab report. The grader wrote "Mabey (sic) you're in the wrong major" on the top of my report. Mabey he was right. ;D

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Nope. Will start there. Thanks.

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You mean a Sziklai?

I noticed that a lot of power amps use the Sziklai pair vs. the Darlington. Is the Sziklai demonstrably superior?

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Ah, thanks. You know, the title sounds similar to some texts my dad has. I'll have to examine his library.

Michael

troubleshoot

I agree. As you point out elsewhere, things have moved from learning these details to using functional blocks created by others who know. That's too bad in some ways. In others, it means more people can have at it without having to spend so much time informing themselves well and fully, I suppose.

I'm just a hobbyist and in no way do I imagine I understand all of the important details. But I've cobbled together my own designs for a few usably working audio amplifier circuits, when I was much younger. And at least for me, learning things in discrete steps helped a lot. At some point, it's time to figure out how to combine functions a bit. But to start out, separating them seems to help. For me, it did.

Part of this will be learning about conditioning the input source appropriately and well. Degenerative voltage amplifiers aren't that hard to understand and design and may be a good place to actually start. In that regard, the student manual for the Art of Electronics is important -- the book doesn't cover the details well enough on its own -- if that book is to be used. The student manual includes a "compute this first, then that second, then..." approach. Very easy to follow. (Then include bootstrapping of the input from the BJT emitter as a 'next thing' to gather well.) As you also point out in another post, emitter followers for output.

Although some of these functions can be combined in a given design, I don't think I could have handled it when I was going through this. It was the fact that they could be taken in steps that allowed me to succeed, as much as I did. So I recommend taking this in parts.

I started out trying my hand at understanding the basic degenerative BJT amplifier, then gaining a foothold on the bootstrap to stiffen the input a bit. I used a well designed power supply, a well designed signal generator, and a well designed oscilloscope as tools -- designed by professionals while learning about simply voltage amplification. (It's remarkable to me how complicated it all seemed at first and how so much simpler it seems in after-thought, looking in hindsight.) It was after that when I began worrying about how to work with various input sources worked; sometimes their own supplies and in all cases some kind of matching to avoid distortion or avoidable loss of signal. I actually built my own carbon granule microphone, in fact. Most of my experience was with dynamic microphones, but later this included electret. Then I worked on outputs (mostly just the typical 4-8 ohm speaker, but also various kinds of headphones.) One such I also built by hand, winding wire, using fixed magnets, and using tiny metal plates as diaphrams.)

It was fun but took a lot of time. I made stuff that didn't work well, too.

I learned this stuff in the late '60s and early 70's, when I had the time as a kid and young adult, too.

Jon

I remember building that ! If it didn't get lost when we moved it will still be kicking around in a box in the garage ! I might even still have the original magazine.

Just Lurking :-)

sensible

Idiot! The PN2222 is the same die in a TO-92 package, and the MMBT2222 is the same die in a SOT-23 package it isn't obsolete, just repackaged for modern designs. 2N2222 is considered the generic name for the family, since it was first. Both the 2N2222 & the 2N32222A are in stock at Digikey, which means the metal cased TO-18 package isn't obsolete for all designs.

have

subsequently

Typical British design quality.

knows

Mr

C programming is still very useful. Apart from C itself, C++, Objective-C, Java and C# are all heavily based upon it.

Assembler isn't so useful in application programming, but it's still useful if you're programming microcontrollers, or writing system code (OS kernels, compilers, interpreters), or performance-critical applications (e.g. games). Although most of the above is written in C or C++ rather than assembler, being able to mentally translate into assembler will result in much better code than that written by someone who only understands the language as a theoretical abstraction.

I remember it! There was a follow-up article with another version, as I recall.

Jon

That "bizarre" syntax is pretty much the > How could you be offered a job in C programming if you didn't know C

In 1984, C was still a fairly uncommon language. It wouldn't be unreasonable to prefer someone with a reasonable amount of overall programming experience (particularly if it's experience in the relevant domain) who would need to learn C over someone with less overall experience (or less relevant experience) with some C. Learning a new language is easier than learning programming.

Of course, that doesn't hold if hiring is done by HR types with no knowledge of the field (and no willingness to consult). A classic example was when Java took off, companies were advertising for programmers with 2 or 3 years' Java experience when Java's existence had been public knowledge for less than a year.

Ah. Found them!

Jon

You probably mean this

which I built in high school. It had an annoying tendency to blow the outputs. And this

and another family member

Enough of memory lane for now.

G=B2

All of those tended to fry your speakers?

Michael

Yes, I remember when Java was new. Makes sense from that perspective. But I'm surprised why a seasoned programmer would run away screaming from C.

I liked C as a less verbose version of Pascal.

Procedure Execute; Var i:array[1..10] of integer; Begin End;

becomes

void Execute() { int i[10]; }

What's not to like? :D

Michael

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sensible

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sensible

I'm stunned, especially as it's a European device. They must have a customer who's been using them for years and never changed. Most people moved to using TO-220 devices instead of TO-126 like the TIPs.

Graham

subsequently

Typical SINCLAIR design quality.

Graham

by a

I know. Its parameters are still inferior to later similar devices though.

Do you have a problem with using the correct prefix ?

Graham

Starting to look a fraction more modern ! Diodes proerly coupled to the heatsink too for prevent thermal runaway. ;~)

Still no emitter Rs on the 'power' devices though.

Graham

The fact it's old and uses circuit techniques that are well-dated now means that you're more likely to learn bad practice than good though.

Graham