Some help please

[D1lazarus]

I have a homemade varmint call that I need to power better than with the little 9v battery that goes in the little amplifier that I have.

Radio Shack Model: 277-1008 Amp Mini Audio Amplifier - RadioShack.com
Radio shack Model: 40-1445 PA horn 100-Watt PA Indoor/OutdoorPowerhorn - RadioShack.com

What I would like to do is use a couple of 9.6v hobby batteries to power the system through the 9vDC jack on the amplifier.

Something along these lines **broken link removed**

Any help or ideas that you guys could provide me would be great. As detailed and idiot proof as possible would be great.

 

[audioguru]

The RadioCrap Mini Audio Amplifier uses an LM386 audio amp IC. Its output is only 0.45W at clipping into 8 ohms when the 9V battery is new. The 9.6V battery will not make it any louder, the huge battery will just last a lot longer before it needs charging.

You want to use a couple of 9.6V batteries which is 19.2V? Then the poor little LM386 will blow up because its absolute max allowed voltage is only 12V.
With a 12V supply the output is only 0.53W at clipping into 8 ohms which is only slightly louder that the 0.45W with 9V.

If you use a car radio amplifier IC like a TDA7240A with a 19.2V supply, then its output will be 18W at clipping into 8 ohms. With a 9.6V supply its output will be about 3W at clipping into 8 ohms.
The schematic and a pcb design are in its datasheet.

 

[D1lazarus]

Thanks for the info. I guess I didn't explain very well. Loudness isn't the issue it is battery life. The regular 9v battery doesn't last as long as I want. That is why I wanted to run either a single or dual 9.6v and then step the power back down so that it can run the amp for much longer periods. That and the ability to recharge with equipment that I already have for my RC cars.

 

[audioguru]

The RadioCrap Mini speaker will work fine with one 9.6V/3000mAh battery.
This battery will last 6 times longer than a 9V alkaline battery and 17 times longer than a 9V Ni-MH battery.

 

[D1lazarus]

Very cool thanks for the info. Now the question is what do I need to make the connection? Thanks again audioguru.

And if you have a better idea for an amplifier that I can use to run that speaker off of an mp3 player any suggestions are welcome.

Oh and while you are thinking on it some kind of a remote control unit that would work at 100yds would be great too but not required.

 

[audioguru]

I would not connect a powerful battery to a plug. If you put the battery in your pocket and the plug touches keys or a coin then your pocket will be on fire!

The RadioCrap Mini Speaker has a jack for a low level input signal. Connect a turned down MP3 player.

 

[D1lazarus]

Nope I get that. Already using an MP3 player to play the varmint calls. Just need to know how to hook the 9.6v battery up to power the amp.

 

[audioguru]

Connect a jack to the battery and use a cord that plugs into the battery jack on one end and plugs into the Mini Speaker at the other end. Get the polarity correct.