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
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
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 !
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 !
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).
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.
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.
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.
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... 😛) to a 12v 2.1 amplifier?
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.
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.
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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 😛😀
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 😛😀
Oh yes ! The load is part of the total Watt RMS calculation too !
2.8-3.2 Ω speakers are frequent !
2.8-3.2 Ω speakers are frequent !
A lot of those digital-fangled amps are bridge amps. Is that a bridge amp?
You're going to be hard pressed getting enough power for one speaker from a USB port. let alone three.
I guess you have modest aspirations.
You're going to be hard pressed getting enough power for one speaker from a USB port. let alone three.
I guess you have modest aspirations.
@Robotob46 . Just to clear things up.. Do you intend to use this on USB?. If not why is your battery voltage limited to 5 volts ? Can you not use a 12V battery ? It would make it a lot easier to realise a 2.1 system .. Also you state 2.1 are you after a decent amount of bass? what sound levels are you expecting? Sorry for all the questions.
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Ahh the plot thickens .. I see you are wanting to build a portable Bluetooth speaker. Im guessing the 5V limit is imposed by the Bluetooth receiver electronics .. What exactly are you attempting to achieve ?
It looks like someone really put their thinking cap on when they designed that thing.
I think Linuxguru has it cornered. The two caps on board could be used as a charge pump. In plain talk, the capacitors are charged just like batteries, then the circuit/chip ~connects them end to end REALLY FAST i.e. like two five volt batteries, to produce 10 volts. *IF* you are really interested you can get a data sheet for an ICL7660 for an example of how it is done.
But yes, a USB port will not supply anything near the kind of current you are looking for to play at full volume. *IF* your design uses a wall wart type USB charger, they are typically available in 1.2-2.0 amp range and could approach it. Another option would be a powered USB hub, but then you are losing the advantage of low price to get it running.
I think Linuxguru has it cornered. The two caps on board could be used as a charge pump. In plain talk, the capacitors are charged just like batteries, then the circuit/chip ~connects them end to end REALLY FAST i.e. like two five volt batteries, to produce 10 volts. *IF* you are really interested you can get a data sheet for an ICL7660 for an example of how it is done.
But yes, a USB port will not supply anything near the kind of current you are looking for to play at full volume. *IF* your design uses a wall wart type USB charger, they are typically available in 1.2-2.0 amp range and could approach it. Another option would be a powered USB hub, but then you are losing the advantage of low price to get it running.
The OP never quoted he needed to run the amplifier from the usb port.. from what I have read of this thread he states he wants to run it of a battery. I think the confusion is caused by the title of the link he posted for 5 volt usb 2.1 amplifier. He has ideas of building a Bluetooth speaker amplifier system. Just check his other thread..
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