Quick question about Amp/Speaker Wattage

[Markyo]

Hey,
I am trying to build a little portable Bluetooth speakers set.
I have a 15w amp, and only speakers i could salvage are 3w.

Would they blow if i test out the amp on them?
If i keep it under 1/5th of the volume would it be alright?

Hopefully be able to connect up my bluetooth module as the input, and the plan is to have two or three lithium batteries (seperated so hopefully il get 4-8hours out of each, and know where i stand with remaining battery time).

Just googled electronics help and this is the first link that came up =) looks like a class site!
Thanks =)
Mark

 

[Markyo]

And actually, the amp is dual channel 15w amp.

Just double check that the output is 15w to each speaker? opposed to 7.5w to each.
The description on the site sounds like 15 each, just to be sure =)

 

[Markyo]

Just realised what i thought was the input for audio, is actually input for power..
On dx.com it says "Input voltage: AC18V, DC24V"
what should i use to supply this power? =)
Thanks

 

[davenn]

Just realised what i thought was the input for audio, is actually input for power..
On dx.com it says "Input voltage: AC18V, DC24V"
what should i use to supply this power? =)
Thanks

no you mis-understand ... it is an audio amplifier chip and the chip is rated for 15W into 4 Ohms
the circuit board can take 2 chips and assoc components and therefore you can make a stereo amp with 15W per channel

On dx.com it says "Input voltage: AC18V, DC24V"

that's referring to the power requirements


if you keep the volume level down, the 3W speakers will be OK. just save up for or look out for a 2nd hand set of higher power speakers and cabinets ... something around 20W each
Dave

 

[Colin Mitchell]

When the volume is turned down to a low output, the 3 watt speakers will only be seeing 1 watt. As you turn the wick up, you will see the cone move to its full excursion. That's as far as you can go.

 

[Markyo]

Okay cheers,
how would ye go about powering it?
What would i need to power from a battery?

Had a quick google there to convert battery to AC power. But the results i see are converting battery powered devices to run on AC power.

 

[Colin Mitchell]

You need a 12v battery or plug pack. The plug pack can be AC or DC. The maximum voltage is 18v but you can use 12v AC or DC plug pack.

You can use AC or DC and you can connect the wires either way to the board.
This will give you a low wattage amplifier - just what you need.

 

[davenn]

The maximum voltage is 18v but you can use 12v AC or DC plug pack.

18V AC or 24VDC

 

[Colin Mitchell]

"18V AC or 24VDC"

Yes, but he has only got 3 watt spkr and so the max voltage should be about 12v to 15v

You can get the 3 watt stereo version for 70 cents with free postage and all the hassles are over

http://www.aliexpress.com/item/PAM8...6c41f5847a&crm_mtn_tracelog_log_id=6171218435