So I'd really like to get into circuit design/electrical engineering type stuff. It's really peaked my interest as of late. After I visited a buddy of mine who's self taught and seeing the amplifiers, filters, delay, and crossovers he has built I have a really strong desire to start learning the stuff. There's a community college near by that I could probably take some courses at on the cheap, but I'm a little short on money right now and I'd like to have some understanding of concepts before I start class. Just wondering if anyone knows of any good places to start on the web. My ultimate goal is to design and build my own audio related devices that I can incorporate into music production. Thanks guys.
Go to library, find basic electronics book, read? How much electronics do you know now? If none at all then make sure to get the basics drilled into your head. If some, then make sure you have the basics drilled into your head before jumping ahead to more "fun" stuff. By basics I mean resistors (and variable resistors/LDRs etc), capacitors, switches/power, diodes/LEDs/transistors. Then move onto logic gates, op-amps and the like.
This site has all the official support material for the A-Level Electronics course I did. It starts with the basics, but also includes audio circuitry later on such as amps, tuning curcuits, transmission and bandwidth etc... http://www.wjec.co.uk/?subject=49&level=21&list=docs All the resources are available for free without registration.
Theory without practical puts me to sleep. I remember building my first amp as a kid however, it was very fascinating to read up and learn about every intricate detail of the circuit, and then went on and learnt how to improove the performance of the circuit, or alter it to better suit the application, etc. It's much easier to learn and remember from experience, than from just reading about it alone. tl;dr built a hifi amp kit, learn everything about it on the site mpe91 linked
QTF! I gradutated from Manchester last year with a first in electronic systems engineering, taking that course was the biggest regret of my life, we did almost no practical work and almost nothing on circuit design, which coming from the a-level course where it was the opposite way round was a massive let down.
I built my first guitar pedal this year so I assume you're in the same boat as me (ie bugger all electronics experience!) It's pretty hard to get your head around to start with but what worked for me was to find some VERY basic designs on the internet and get to work building that. Think anywhere between five and ten parts to start with. You can pick up small quantities of parts and equipment from Maplins to start with, if you ever need bigger volumes though it's better to go elsewhere. Oh, a 'breadboard' will be invaluable! It lets you build the circuit without having to solder anything. I used this to build a couple of circuits and then change parts in and out to see what effect they had on the sound. Some people say you should'nt just throw things in and 'see what happens' because you can burn the odd part out which is fair enough, but to me the learning was more important than frying a 10p LED! You can sit and learn the voltages for things (and you should!) but honestly you need to hear the result to work out just what that part is doing to the produced sound, which I'm assuming will be the end goal of your build. One last tip, don't give up. It took me three days of headscratching and frustration before I got anything workable out of my breadboard, but that's because I was very very new to it all. So don't get stressed if it doesnt work on the first build, take a half hour break and go back to it, you'll spot something you did'nt before Enjoy it!
I'm already very familiar with all of the components you mentioned. I've got plenty of tools around to use at my disposal, like breadboards as mentioned above. I'm great at soldering. I'm very mechanically inclined and usually pick up this sort of thing very quickly. My first goal is to build an amplifier. I'm a musician and I've built up a very nice, heavily acoustic treated home studio with some top notch monitoring. However the amplifier I use is some crappy radioshack brand. The gain structure must be rather off, as barely moving the volume knob will get me to near peak output wattages. Not to mention all the hiss I get from it. mvagusta, can you tell me a bit more about the kit you built? I've seen a ton of kits online but I question their output and overall quality. I'm referring to these. http://cgi.ebay.com/TDA7294-dual-ch...876?pt=LH_DefaultDomain_0&hash=item19c17c95b4 http://cgi.ebay.com/Tube-6N3-Preamp...ultDomain_0&hash=item19c09964ec#ht_4711wt_905 (I know it's got a tube and I'm weary of those as it is) Parts will not be an issue as there is a massive, I mean MASSIVE electronic parts warehouse very close by. I'm talking three floors of parts. If you can't find it there then it doesn't exist.
My first amp build would have been about 16 years ago It wasn't that different to the first one you linked from ebay, but the TDA7294 chips that one uses aren't HIFI, as you can see on the datasheet: http://www.datasheetcatalog.org/datasheet/SGSThomsonMicroelectronics/mXqwvzw.pdf If you scroll down to ELECTRICAL CHARACTERISTICS on page 3, you can see that the output is a very clear HI-FI .001% THD at 5w... but at 50w the THD is .1% which is a fair bit worse than the HI-FI standard of .005% The chip can output 100W with a capable psu, but the distorsion goes up to 10% = very fuzzy sound that would damage speakers and ears in no time Simply studying this datasheet with the help of mpe91's link, will teach you heaps about electronics, but since you want a HI-FI amp, just check the specs for any kit you find - any quality amp will usually brag about how clear it is. You could mod that radio shack amp btw, which would be very educational. Improving the grounding and shielding can remove ALL traces of hiss, and adjusting the gain control shouldn't be too hard
Ah yes, THD. I'm familiar with that, so I feel kinda dumb for not even looking for that. I suppose I could modify this amp, but I wouldn't know where to begin. I suppose I could replace the pot.
If you don't know much about electronics and electronics 'language' some can find it quite hard to pick up to start with I think. Just to let you know you have a long way till you know wnough to start designing amplifiers/audio kit if this is what you essentially want to do I don't know! Good luck.
It wouldn't be as simple as just replacing the pot, which might possibly not need replacing. You could start by unplugging and opening up the amp, and taking a few photos, and we could probably point out one or two weaknesses in it's design, and we can point out a few places where you can take measurements to further analyze the amp's circuitry. You wouldn't need to take much care to avoid potentially receiving a small shock from any caps, basically just avoid shoving your fingers into the circuitry Once we see the photo's we can point out what everything is, and you can then search for detailed technical descriptions of them. Doing the above is basically reverse engineering, and it is kinda jumping in the deep end I guess. It is easier to do build and learn from a kit, as not only do we have a complete circuit diagram, but usually also a detailed and educational description of the circuit's operation. Maybe just continue searching for HI-FI/low THD amp kits, and link them for us to review.
I have an old book I learnt on called mike tooleys electronic fundamentals its great and a great place to start.
If you are going to get into serious electronic design you must know in depth theory, it's impossible without it.
V = IR There, you're done. Everything else just sort of *works*. I'm convinced there's a maximum of four people on earth who actually understand capacitors and don't get me started on inductors, the rest of us sort of just blag it.
CBA reading all replies, but try MIT Opencourseware, you might also find that MIT Edx will have a course on it in the not-too-distant future.
I have just about enough knowledge to get by for both but my experience is that that's the case for the majority of people (at least for people I know). I speak mostly in jest but it certainly seems to be the case that lots of people shy away from in-depth analogue electronics.
