How can I power my amp (200w) to make it portable (away from the car)
 

Hi,
I have a small 200w amp, and i would like to power it so i can carry it around (in a rucksack, with some small "6 speakers. little project im working onv:D)

So basically some sort of battery design and I have no idea where to start :dead:

Any help appreciated, Thanks

I don't know of any 200W amps that are "small", but you could try one of several routes:

1) If it is a car amp, simply pack a good sized gel-cell or suitable AGM battery, and let 'er rip;

2) If it is a home amp, then you could use a DC-AC Inverter (of appropriate size), and the aforementioned battery;

3) Determine the operating voltages, and replace the bipolar supply with a bipolar battery of equivalent voltage, charging it when you are back near a source of AC power

-or-

4) You could try doing an SMPS DC-DC converter, stepping the voltage up from 12V to whatever +/- voltage(s) your amp will need. There are quite a few threads on the Forum regarding SMPSing for Audio.

Hope this helps,

Steve

Hi,
increase your speaker sensitivity by 10db and you only need 20W of amplifier power.

Go for 20db more sensitive speakers and you only need 2W of power.
A 4Ahr Nicad might just do if the amplifier is designed for efficiency.

thanks for the replies people. How can I find out what the operating voltages are?

Is this a home- or car-amp? first, It ould help to have a schematic. See if you can ordere the service manual, complete with schematics.

Second, without any more info on the amp, it's darn-near impossible to say where. I would look for the BIG power supply capacitors

BIG power supply capacitors.................
 

Wow! I must've fallen asleep during my last posting- I just noticed I stopped in mid-sentence.

I think I was saying something finding the operating voltage(s) in the amp, by looking for the BIG capacitors and perhaps a BIF inductor.

You still haven't answered the big question: Is this a home- or car-amp? The difference between the two is the voltage(s) you will find inside them, and the types of safety protocols you will need to observe.

If it is a home amp, BE ADVISED: You will be dealing with LETHAL voltages: like 120VAC, 220-250VAC, 320-350VDC, etc. etc. Anything over 60VDC is considered lethal. In Europe, 50VDC is considered the threshhold for lethality. If you want to take it portable, try constructing a DC-DC Converter from 12V to whatever the amplifier's +/- operating voltages are. Insert it into the amplifier circuit tapping at the (+) and (-) bus bars. THen, whenever you're at home, you will be operating off the AC mains, and when you're on the road, you can use the battery.

If you have a car amp, you might not be dealing with high voltages, (though +/-45V to get 200W into 4 Ohm isn't exactly considered low voltage :D), but you will be dealing with very large currents. Like, on the order of 30A & up. While not lethal, shorting one of them out CAN yield a pretty spectacular fireworks show!

Typical operating voltages you should see for a 200W amp would be +/- 60-65V for 8 Ohm operation, and +/- 45-50V for 4 Ohm operation.

Let us know what type of amp it is (home or car) and we can give you more specific advice.

Steve