Amplifier for Bluetooth speaker

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Hello, I'm new to the world of portable audio and I'm trying to make a Bluetooth speaker.

So, right now I have 2x10w 4ohm speaker and I need an amplifier to them.
I was thinking to buy a more powerful chip to deliver 2x10w with less THD+N than a simple 2x10w and them somehow, limit the power to not burn the speakers.

Getting in consideration I already have a Bluetooth receiver, that isn't important to the module integrates one.

I'm planning to use a 12v lithium battery (with a step down to power the BT receiver) and wanted it to be possible to charge with USB (so step up to 12v to battery?).

After this little explanation of what I want to do, what amplifier do you recomend for this?

Thanks in advance,
eX Radikal

P. S.: I've searched a little bit the forum before asking this question but came with no answer because everybody talks about too powerful amplifiers or to use in somewhere else but in a small BT speakers.
 
Well I am rethinking the amp to speaker match up but I am currently thinking of using this set up. How ever it might be too much power for the 2 inch speakers so I might go with a less powerful amp
 

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I ended up buying this one. Digital 2.1 Channel Amplifier Board Bluetooth USB Input 50W+50W Stereo 100W im | eBay

I liked how there is space on the circuit board which will hopefully produce a cleaner signal plus it looks like it was a lil bit more quality, It also has the bluetooth built in

Also the power going to the speakers depends on the supplied voltage so if I keep it at 12v I should be good, I also changed my sub woofer from the 100 watt to 20 watt as the lower 12v brings the amp in around 15watts output to the sub
 
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So the kool thing about amps like this , is its based upon the power I supply to it. So at 12v input it is out putting less than 35 watts.

THD? I do not what that is

There are plenty of other 2 channel amps that will work for what you want.
This one is not bad either , a lil over powered for what you want

TDA7492 Bluetooth 4.0 Audio Receiver 2Channel Power Amplifier Board 50W+50W N5D8 | eBay


I would also look at pics of the board, and if it looks like stuff is put on there crooked or if its crammed in there, I would pass. I was going with a amp that was half the price, but when I compared the two boards, the board I picked was just so much cleaner looking and well made, but at a higher price.

My original budget was $100 but I am now at $138 but I ended up going for quality over price. And I still might add a crossover to it as I have not found an answer to a question regarding 3 channel amps that have a sub woofer out on them, do I still need a crossover?

But anyway I will start a build thread, I am cutting wood today.
 
Thank you in advance.
I had investigated all of the you suggested and all behave +/- the same: neither of them can deliver a clean 10w per channel with a 12V power supply (too much THD).
So, if I can't find a 10w per channel with (very) low THD, I'll probably buy a TPA3116D2 and somehow limit their output power to ~10w.
 
Portable tpa3116d2 speakers

If you look up the popular XH-M190 version of the TPA3116D2 you will notice it has a volume control potentiometer built in. Set it about halfway up. If it sounds like the speakers are straining, turn it down. If it seems like they could use more power safely, turn it up.
Later on, when you find some better speakers, turn it up all the way.
If you are using 12volts, they will only be making about half their rated power anyway.
 
One more question, can anyone explain to me how the "commercial" speakers can use 3.7v batteries and get 20/30w of power? For example, JBL Charge 2/3. Are they using simple voltage boosters/step-ups?

They do (JBL Charge 3) 2x10W into 4R. In BTL, this translates to 6.3Vrms or 8.91Vpk. So they boost to a moderate 10V i'd guess. This is, of course, peak power, so the battery needs to supply 2x10Wrms -> 2x20Wpk / 0.85 efficiency = 47W or 23.5W per cell. (Two cells are connected in parallel)

So, 6.35A per cell (peak) or 2.1C (calculated againt 3Ah capacity per cell)

These speakers use heavy psychoacoustic manipulation by DSP to "sound" like that.

Frequency response of the charge 2 is shown here:

jbl-140-141.png


Source: Oluv's Gadgets: News: Finally! JBL Charge 2 - 1.4.1 firmwarefix

The JBL Charge 2 is working with a TPA3130, like shown here:

tM3aoFRWj2A.jpg


Source: Oluv's Gadgets: News: Finally! JBL Charge 2 - 1.4.1 firmwarefix

The JBL Charge 2+ is rated at 2x7.5W
 
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Thanks for the answers.
#saabaab, I've thought of doing that. Not exactly with the potentiometer but just simple limiting the input. The potentiometer is a good and easy way anyway.

#doctormord, I tried to understand the first part with the calculations but got a bit lost. So, basically, they use 2 cells in parallel so they can supply 23.5w each. Each of this cell is still 3.7v, so, you are saying they boost to ~10V with a step up/booster?
I was about to buy one 12v lithium battery to use in my Project (probably using a tpa3116, still didn't bought it too). Do you recomend me to buy 18650 cells and a booster instead?

Also another question, is there any mini board/module that is adequated to use in projects like this to compress/limit/EQ the sound so it can sound "more sweet" (refering JBL Charge 2+, that I've listened to and love the sound, especially in low volume, they probably compensate the bass)?

Thank you so much for your attention :)
 
Well, let's discuss the battery system after the amplifier is choosen. I've selected a few boards from eBay, 5 3116's and 1 3118 only. Which one do you think is better (I can mod it after too, so consider that)? Do you recomend still another board (that isn't lots more expensive from this price range maybe)?

TPA3116:
1 - 1Pc TPA3116D2 2x50W Dual-Channel Stereo Audio Digital Amplifier AMP Board | eBay

2 - 50Wx2 TPA3116 D2 Dual Channel Digital Power Amplifier Board Stereo DC4.5-27V | eBay

3 - 2.0 HIFI 50W+50W TPA3116 D2 Audio Power Amplifier Digital Completed Board | eBay

4 - 2x100W TPA3116 D2 Dual Channel Digital Audio Amplifier Board 12V-24V for Arduino | eBay

5 - TPA3116 D2 120W+120W Dual-channel Stereo Digital Audio Power Amplifier 12V-24V | eBay

TPA3118:

6 - DC 12V-24V TPA3118 D Class Digital Audio Amplifier Board 30W*2 Power Amp Module | eBay

Thanks in advance,
eX Radikal
 
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Of the numerous 3116 boards I've used, the one above is one of the worst; very noisy with bad distortion. It improved slightly when I bypassed the volume pots.

Of the ones I have tried, these are my preferred boards:

Assembled TPA3116 class D amplifier board 50W+50W (green pcb) | eBay

New TPA3116 100W 12V-24V 3A Mono Digital Audio Power Amplifier Board BTL Out Amp | eBay
 
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