[coinmaster]

Heelo. I've been considering making my own amp for a while now. I have a basic understanding (more or less) of what the different components do individually.
What I don't understand is how they come together to make a headphone amp.
When I see the inside of headphone amps I see what seems to be a circuit made entirely of capacitors and resistors.
I'm not sure what role the caps play other than smoothing out the current.
What exactly goes down in amplifier circuitry? What separates a low quality amp from an amp costing thousands of dollars?

 

[superjawes]

In short, an amp takes a small signal and basically adds power to it so that the output signal is bigger.

Capacitors and resistors are purely passive devices, so they cannot amplify anything. If you want to add power, you need something like a transistor or vacuum tube. What makes the quality difference? Well, a lot of things. The specs of your transistors/tubes can make a difference. You also can get a big difference from all the supporting circuits used (those extra resistors and capacitors included) to bias transistors (to keep them "on"). Also, many amplifiers are going to have multiple stages, as some basic designs are going to be good at getting voltage gain (making the signal bigger) while another will be able to source the current (power = voltage * current).

Once you have an amp built, then you can start testing it and seeing how it measures. You can check the frequency response (how well the amp passes different frequencies), total harmonic distortion, max power output...and then you can, of course, actually listen to it. Some amps will just sound better than others, especially when paired with a load (headphones or speakers).

 

[Mr Rick]

  Heelo. I've been considering making my own amp for a while now. I have a basic understanding (more or less) of what the different components do individually.
What I don't understand is how they come together to make a headphone amp.
When I see the inside of headphone amps I see what seems to be a circuit made entirely of capacitors and resistors.
I'm not sure what role the caps play other than smoothing out the current.
What exactly goes down in amplifier circuitry? What separates a low quality amp from an amp costing thousands of dollars?

If you seriously want to learn about electronics, I suggest you start with this.
 
http://www.amazon.com/Understanding-Basic-Electronics-Softcover-ARRL/dp/0872590828/ref=sr_1_8?ie=UTF8&qid=1424985044&sr=8-8&keywords=arrl

 

[HotIce]

By far the best read on audio amplifiers is the Douglas Self book, which is also available as PDF (old version):

http://www.unge.gq/ftp/biblioteca%20digital/Amplificadores/Audio%20Power%20Amplifier%20Design%20Handbook.pdf

If you are into it, I suggest you buy the latest version of the book.

 

[coinmaster]

After a few days of reading on circuitry and electricity I'm realizing what a vast monumental task it is have the  understanding needed to make an amplifier, I practically have to go to school for this. 

 

[superjawes]

Actually, "making" an amplifier just requires a bit of soldering and assembly skills. "Designing" an amplifier is quite a bit more complicated. And yes, most people who design amps professionally go to school for it.

 

[HotIce]

After a few days of reading on circuitry and electricity I'm realizing what a vast monumental task it is have the  understanding needed to make an amplifier, I practically have to go to school for this. 

 
Yes, if you want to understand (and you really want to, otherwise there is no point in designing electronic circuits), you need to know the theory.
I went through some reviews some time ago, to pick up a starter book for my nephew, and I ended up picking him up this one:

http://www.amazon.com/Practical-Electronics-Inventors-Paul-Scherz/dp/0071771336/

He liked it, and he was able to easy follow the book, with his last year of high school education.

Most of the HP amps these days are just a couple of feedback resistors around an OPamp, and that should be easy to grasp anyway

 

[wakibaki]

  After a few days of reading on circuitry and electricity I'm realizing what a vast monumental task it is have the  understanding needed to make an amplifier, I practically have to go to school for this. 

I remember in my first year of uni. electronics, the professor came in one day and said, 'OK, I'm taking the class today. One thing you all need to know, is how to design an amplifier. Relax. I'm going to explain how to do it.' And he did. In less than an hour.
 
Of course it wasn't a full scale audio power amplifier, just a single-stage common-emitter baseband amplifier.
 
That lecture depended on everybody being up to speed on a whole lot of other stuff, however. Against that, we also learned a whole lot of stuff irrelevant to amplifiers, like telephone switching theory.
 
So, yes, it's true that there's a lot to learn, but it's not like you have to learn the whole of electronics. You just have to get somebody to coach you with the bits you really need, there aren't any books I know of that are focussed on audio that take you through the relevant basics, although Morgan Jones has some good introductory stuff in his books on valve amplifiers. It wouldn't hurt to look at Tangent's site.

 

[coinmaster]

I read about 100 pages of "Grobs Basic Electronics" and it seems like it would take a year to learn everything. It just keeps getting more deep and complex and holy crap the math

. I always hated math

 

[HotIce]

Doing electronics w/out math, is like showing up at track day w/out a bike
At the very minimum you need some basics of complex numbers (Z) math, because phase information comes with it.
And you really want to understand phase, and how it plays with amps negative feedback.

 

[wakibaki]

  I read about 100 pages of "Grobs Basic Electronics" and it seems like it would take a year to learn everything. It just keeps getting more deep and complex and holy crap the math

. I always hated math

 
Lots of people find that maths is much easier to deal with when it's applied to something they're interested in. I used to hate trig identities. I used to think they were as useful as the Latin I had to learn. Now I have a use for them. You might find the same thing.
 
The Latin comes in handy for writing prescriptions.

 

[superjawes]

The math difficulty in electrical engineering depends on what you're doing. Signals analysis and electromagnetic fields/waves are the most math intensive. The hard part of analog design--in my experience--is making sure that you are modeling the circuit correctly. Basically, semiconductors don't behave linearly like resistors and capacitors, and you have to force them to behave a certain way in the DC realm before you move into the AC realm...that can get confusing.

If I was actually designing an audio amplifier, I would hope that I had a CAD tool to help out...that lets a machine do most of the math for you

 

[HotIce]

I use KiCad pretty extensively. From circuit design, to PCB. Love it.
So yes, ngspice/pspice make the work for you, but you really have to understand what is going on, before letting a tool speed up the calculation for you.