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Quick question about Amp/Speaker Wattage

Markyo

Jun 6, 2015
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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

Jun 6, 2015
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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

Jun 6, 2015
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Jun 6, 2015
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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

Moderator
Sep 5, 2009
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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

Aug 31, 2014
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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

Jun 6, 2015
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Jun 6, 2015
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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

Aug 31, 2014
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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.
 
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