Electronics Advice

dav1d

dav1d

dav1d

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Joined
4 Oct 2003
Posts
650
Right, don't really know where this should go, but GD will do for now.

Basically, I'm looking for some advice on how to go about building some homemade portable speakers for my iPod. In particular, the electronics on how to drive speakers, basic amplifier circuits and using 3.5mm jack inputs.

I've got some electronics knowledge - made circuits with transistors, 555 timers, op-amps, logic gates at school. So if someone could point me in the direction of some good web sites for the basics of audio electronics, that would be great (yes, I have googled already, but don't really know what I'm looking for specifically).
 
I think you can create a very basic transistor amp similar to -see here-

Ill be talking to a guy who knows how tomorrow ill ask for you then. It might be worth taking a trip to a electronics store to get a bit of background info :D
 
Don't bother with the trip to the electronics store, they don't have a clue, except maybe one. I know this cause I work in one, and I don't have a clue.
 
Google search for DIY speakers and DIY amplifier designs. For a beginner I would buy pre selected "kits" that everything is included...you just build up.
 
Efour2 said:
Argos sell speakers, will save a lot of time and effort and sound better. :p
Click to expand...


I reckon you could easily make speakers that sounded way better than cheap argos ones? Surely?
 
I know how to make a speaker, we made one in Physics. We created a cone out of paper and put a magnet in which was wrapped in wire, it just made a simple pitch though. May I ask why you wont to make headphones? May I suggest buying a really cheap pair of headphonees and doing the manly thing and smashing them up? ;)
 
I wouldn't mess about with discrete transistor designs, they are very difficult to implement and expensive. Use a chip-amp. They are avialable in lots of power outputs and often sound excellent. Try the LM384N chip for 5WPC, national semiconductor make many good ones if you can find somewhere to buy them:

http://www.national.com/VCatalog/vi...c0=e:0//Category//:eq//Audio+Products&tId=119

Alternatively try the NJM2073D, its stereo so you only need 1 chip, 2W channel. Or, go mad and use a pair of TDA2030AV like I used in my PC amplifier, but to be portable you'll want a pair of electric drill batteries :D

You could even use a ready made PCB anplifier for pure simplicity, or hack an old one. If you want to spend about £100, do the drill battery thing. Put the speakers in MDF cases, use high effeciency drivers and for pure insanity use the LM3876T, at 56W, you'll be carrying/lugging around 112W RMS of power with you. Battery life may be short, but you'll be able to hear it miles away :p
 
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If your doing it for a project/challenge then by all means try a discrete design, but if you want something simple that performs well then chip-amps are excellent. Here is a discrete design that I have tried (we improved it over at the electronics forum. Actually, you may aswell have the link, it is not a competitor though the site is wierd today)

http://www.zen22142.zen.co.uk/Circuits/Audio/2wamp.html

http://www.electro-tech-online.com/

Anyhow, that 2 watt amp was inefficient, poorer sound quality and takes up more space than a chip version, and without a scope it would be hard to tell everything was safe (no oscillations etc).
 
Yeah, thats what I got, but only as of today, was fine yesterday :confused:

I think i'll wait and see if they change it back then install the thing if not. It's a good board though, just be clear about what your wanting to do when you ask advice.
 
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