Where can I find an amplifier for this portable sound system?

I am working on creating a waterproof sound system to bring to college. I have already created a 3-d model on Google Sketchup and I have two waterproof full range speakers and one 8 inch woofer. I want it battery powered and would either use a lead acid battery or try to salvage enough Lithium Ion cells from old computer batteries to power it for a long enough period of time. The question though is where to find an inexpensive amplifier that will run on 12 volts, is small, and has decent bass. Does anyone know of some websites on which I could find an amplifier? In the past I have bought desktop systems and converted them to battery power (on the rare occasion that they actually run on 12v dc after the transformer and rectifier), so I know it is possible.

Thanks!!!

**edit**

It seems I forgot to include the specifications of the speakers! Anyway, here they are:

2 - "high fidelity full range speaker", 5" dual cone, "power capacity:30Watts system", 7 oz. ceramic magnet, "4 or. 8 Ohms system" (I measured 3.6 ohms with an inexpensive multimeter), They are on Ebay!!

1 - "Model:  Acoustic Audio MARBASS8
Color:  Black
Acoustic Audio 650 Watt 8” Car/Marine Audio High Performance Subwoofer
650 Watts Peak Power Handling / 325 Watts RMS Power Handling
Recommended Power:  30 Watts to 650 Watts
2” Parabolic RFL Voice Coil
60 oz. Magnet
4 Ohm Impedance
Oversized Butyl Rubber Surround
Poly Zirconium Cone
Polyimide Voice Coil Former
Mid Q Design for Versatility in Enclosure Compatibility
Flat Progressive Roll Spider
CEA Cooling Technology
Vented & Extended Pole Piece
Low Carbon Top & Bottom Piece
Weather-Resistant Design"

This is on Ebay too!


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In order to give you the best advice possible, we (the good folks of Instructables Answers land) need more information on the drivers you have, such as power ratings (including standard SPL listings), Ohm ratings, whether or not the woofer is single or double voice coil, and how you intend to use the woofer (separate bridged amp or mono or stereo amp depending on VC configuration).

If the drivers are low powered (less than 5 watts), you could use a couple of LM386 amps to do the job. Anything more substantial may require something along the lines of a Class D or Class T amp. MCMElectronics has a 10W-15W Class T amp on sale for $17.99 that runs on 12V at 1.5A - can use 8 AA batteries. Using rechargeables will require 2 more batteries as they are usually 1.2V per cell. Charging them is up to you and the battery chemistry.

Qa
+1... although you know the model numbers better than I did. :)
Looking at my newest sale flyer from MCM, you can get the same amp for $14.99! Just use source " SC27AE " to get that price. Good til September 30, 2012. Page 3 of the flyer

Qa
gregjd5000 (author)  Quercus austrina5 years ago
Do you think I could use something with more power with the speakers? I can use a 12 volt 7 Ah lead acid battery with it that can power quite a bit. If so, what would be best based on the speakers I chose?
gregjd5000 (author)  gregjd50005 years ago
oh and by inexpensive I mean up to around $40 or $50
You are looking at a 3 amplifier system, unless you can find a all-in-one 12V, 2.1 system to use. By 3 amplifiers, I mean that you have a stereo amp (thats 2 amps) and a bass amp (the 3rd amp). You could run the T-amp I mentioned for the mains (the 5" drivers) and another amp for the sub. Check out Ramsey Electronics for their Class D amps, the UAM2 and the UAM4. They need 18V though. Or you can go back to the 1st page of that search and see what other ones they have that would fit your bill.

While you are at it, you need to total up the amperage draw, as listed in the specs, and make sure that the battery(ies) you use will have a long enough lifespan before charging. Remember, a 7AH battery will supply 7 amps for 1 hour. If your amp draw is 3.5 amps, your battery will perform admirably for 2 hours, then start to drop off.It will continue to work for some time after that, but you will need to plug in after several hours.

Qa
gregjd5000 (author)  Quercus austrina5 years ago
Thanks a ton for the help but it doesnt seem those will work. It will need to be 12 volts and a bit cheaper. One I was considering was this, but it looks a little cheap. I like the idea of a car amp (they are usually made for 12v). Any thoughts?
It has reviews, both good and not so good, but it should work. All I can say is, give it a try. I have no real world experience with them. Go for it.

Qa
gregjd5000 (author)  Quercus austrina5 years ago
Thanks for the info! I just updated the question to include the specifications. Hopefully that will help!!

-Greg