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Chip Amps Amplifiers based on integrated circuits

Good 5v 2.1 output mini amp?
Good 5v 2.1 output mini amp?
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Old 27th June 2014, 08:56 AM   #1
Robotob46 is offline Robotob46
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Default Good 5v 2.1 output mini amp?

Hey there!

Is there a good amp out there that runs off of 5v that outputs 2.1 channels?

This is the only one I've been able to find: 5V USB 2 1 Channel Digital Audio Stereo Power Amplifier Board Module 5W 3W | eBay
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Old 27th June 2014, 12:00 PM   #2
AndrewT is offline AndrewT  Scotland
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5W into 2r0 requires an output voltage of 4.5Vpk
It's going to take an almighty power amp to output 9Vpp from a 5V supply.

This confirms it is actually a bridged pair of amplifiers each rated at 2.5W into 1r0.

Now consider the two 3W into 4r0 channels.
same applies.

All that from a chip that looks about 9mm square !
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Old 27th June 2014, 12:24 PM   #3
linuxguru is online now linuxguru  India
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IIRC, PAM8403 is a Class-D bridged inductor-less solution that does 3W into 4R with a single +5v supply (nothing preventing an integrated charge-pump or similar to convert the +5V supply into dual rails).
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Old 27th June 2014, 08:19 PM   #4
Robotob46 is offline Robotob46
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Okay? I should have mention this in my first post... I am new to this audio thing. If both of you could reiterate into simpler terms that would be greatly appreciated!
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Old 27th June 2014, 10:18 PM   #5
Boscoe is offline Boscoe  United Kingdom
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Quote:
Originally Posted by Robotob46 View Post
Okay? I should have mention this in my first post... I am new to this audio thing. If both of you could reiterate into simpler terms that would be greatly appreciated!
There may be a few amps about that can fulfil your criteria however you have answered your own question with the product you post. They do exist, how good they however who know.
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Old 28th June 2014, 09:10 AM   #6
AndrewT is offline AndrewT  Scotland
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In simple terms:
one cannot get 3W into 4ohms nor 5W into 2ohms from a 5Vdc supply.

There is something else going on inside those tiny chips.

To achieve those levels of power one would need an ampere, or more, from the PSU through the chip for each channel. What distortion is the chip creating in trying to pass an amp to the load?

2.5W into 1ohm requires over 2Amps into the load from BOTH halves of the bridged pair.

It doesn't work.
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Old 30th June 2014, 04:38 AM   #7
Robotob46 is offline Robotob46
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Okay! Would I be able to use a 5v to 12v step-up power converter to go from the battery (portable speaker... Again, forgot to mention this... :P) to a 12v 2.1 amplifier?
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Old 30th June 2014, 05:56 AM   #8
vodka is offline vodka  Argentina
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Power = volts*amps, if you up 5v to 12v but keep power (w) the same, the amps necessarily have to go down... and you're basically in the same situation as you started with but probably a little more desirable one.

I think your best bet on this one is to use the most efficient speakers you can get, so you can make good use of the little power you have available.

Last edited by vodka; 30th June 2014 at 05:59 AM.
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Old 30th June 2014, 06:02 AM   #9
picowallspeaker is offline picowallspeaker  Italy
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No ! well, AndrewT might be too pedantic for the eye of a newbie.
Assume that an amplifier IS the supply, since the voltage at the output
is part of the calculation. So the supply is fundamental. Batteries can be a good
power supply for the (an) amplifier, but their duration...
Supply coming from the mains often, if not mainly ,needs a transformer. For good audio it has to be well made ( not buzzing ! )
The transformer outputs AC so diodes, caps ....RMS...
So a minimum calculation...delivers to about 11-12 V @ 1A
for good 2.1 1+1+3W design
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Old 30th June 2014, 06:08 AM   #10
picowallspeaker is offline picowallspeaker  Italy
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Oh yes ! The load is part of the total Watt RMS calculation too !
2.8-3.2 Ω speakers are frequent !
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