DIY portable music DREAM! (plz read)

[slinky man]

Hi all! Thankyou for reading this thread.
Ok, so this is my plan but i need some help.

My plan is to build a portable speaker system thats inbuilt into a back pack type bag so that i can walk around the city or whatever blaring awesome music out of my bag so everyone can hear it I'm aiming for the sound to be fairly good quality and for this to be fairly cheap.

This is what i got already:
- discman with a power pack (can use regchargeable batterys but i'd prefer not too)
- laptop (has a battery already but i would like to run it without it)
- a cheap set of computer speakers (sub and 2 side speakers)
- a bag

So all that is sorted.
What i need is some sort of rechargeable power supply that can idealy power both the discman (or maybe a laptop) and the computer speakers. Or at least just the speakers. Of course it cant be TOO heavy cause i wanna be able to carry this all in a bag.

I'm thinking something like a car battery or a laptop battery with a power board connected to it so i can just plug my gear in like at home into the wall, but i dont know if thats possible.

- The speakers dont have a power pack or anything so its going to need a good ac 240 volt power source. (I am willing to buy a new set that runs on something simlar to my discman, but it wont sound as good)
- My discman has a power pack so it will do with eather 4.5 volts dc or 240 volts ac.
- My laptop also has its own power pack but in order to charge the battery its going to need the 240 volts too.

Like i said, my lappy has a battery and i got rechargables for my discman, but i'd like to be able to run all this and my speakers off the one power source. If this isn't possible then i can deal with just the speakers being run off the power source.

Is this idea completely unreachable without buying a huge generator?
Any comments, help or advise?

Thankyou in advance

[dangus]

I'd suggest a 12v gel cell battery, 2 to 6 ampere-hours; easy to charge from a regulated supply (just float at 13.8 to 14.4 volts, and limit the current to C(=ampere-hours capacity)/5). Forget about stepping up to 220V. Inverters and transformers add weight and waste power. Run the discman off batteries to simplify things.

Find an efficient 12v amp chip or module; bridge a pair of them to drive the sub (and maybe speakers). Class D or digital amps would be ideal; look around at computer speaker speakers (particularly ones with cardboard cases...) and you may find that same amp that is at Target in the USA.

I once hung a speaker on my bike handlebars in a paint can, and drove it from a TDA810 power amp chip, and it was loud enough to hear over traffic.

[slinky man]

Thanks for your help there mate.
Hahaha off your bike!? Thats a great idea.

I've given up on the sub i got now. It doesn't use a power pack and the amp and transformers are all in really hard to get at places.

I think my best option is:
I'm gunna have to buy a new sub that uses a power pack, then im just gunna chop the pack off and attach it to a rechargable led acid battery thats got all the right volts and amps.

Or i might just make a battery holder that holds 8x D size batterys. I dont think i can afford to buy that other battery and the charger.

I can't wait to walk into my old school libary blaring some dark drum and bass


This will be a fun project. I'll post up some pictures when i've made it.




Does anyone have any more ideas?
Anyone found any nice diagrams i can study? I'm a bit of a n00b when it comes to matching volts and regulating a charger etc.

[loonatron]

What about the chunky 80's ghetto blaster?

I guess that gets too loud in your ears if you carry it on your shoulder!

[slinky man]

Originally posted by loonatron
What about the chunky 80's ghetto blaster?

I guess that gets too loud in your ears if you carry it on your shoulder!

Naa dude. Its not the same idea. I wanna hide it all in my backpack so people aren't sure where its coming from.