Amplifier for Bluetooth speaker

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#41
eX Radikal said:
Hello,
So, it came the amplifier and I've been testing it. It's absolutely amazing the sound of this thing for 5€ +/-. I've connected it to my 100w speaker with 19v power adapter and the result is awesome without any mod (perhaps needs a little more bass refinement).

Is there any chance to add a LED to know when it's on or not?
Also, to get a little better bass, which capacitors do you recommend to use? These are 4x470uF 50V (original??) Sanyo.
Click to expand...

Regarding the LED, the easiest way to do it is to connect the LED to the power supply input - so it lights up when it's under power. Just add appropriate resistor (use any of the online LED resistor calculators...)

As for capacitors, can't help you much with that - but I would change them anyway, since those "SANYO" capacitors are fake in all Chinese amps I've seen so far, and the voltage rating is usually rather optimistic. On some boards those regularly fail within a month...
Use reliable electrolytic caps from reliable vendors, and make them at least 10V over the voltage you intend to use (i.e. use 35V rated if you will use 19V power supply, etc...)

You might also "up" the capacitance a bit - it might help. E.g. if the originals are 1.000uF, use 1.500uF or even 2.000uF - can't really hurt, and extra capacitance might help with bass "impact", since they serve as a power "reservoir" of a kind....

HTH,

Denis
 
#43
Hello!
Is there any topic that discuss how to use 18650 cells/batteries?
I was thinking about buying this
QC3.0 Lithium Li-ion 18650 Battery Quick Charging Charger Module DIY Power Bank | eBay
to charge the cells and use like a powerbank (with QC3.0 capability) then connect the amp and the other things directly to the battery using a BMS in the middle. Looks like a good idea or I simply can't connect a BMS to the batteries because could confuse the "powerbank" module?

Thank you 🙂

P.S. -> I will buy this Bluetooth receiver with the isolator behind. I've bought a few touch buttons so I dont need physical ones.
1x CSR8645 APT-X Hifi Bluetooth 4.0 Receiver Board 12V For Car Amplifier Speaker | eBay
 
#44
First decide how many cells you're going to use, if you need approximately 12 volts, then you need at least 3, that gives 12,6 volts when fully charged. It will drop to about 9 volts when discharged.

With 4S you get 16,8 volts full, and 12 volts "empty".

Then get a appropriate BMS and charger, here's for 4S:

4S 30A BMS Protection PCB Board For Li-ion Lithium 18650 Battery Pack W/ Balance | eBay

EU Plug 4S 16.8V 2A AC/DC Charger Adapter for 18650 Lithium Li-ion Battery Cell | eBay

I think you should forget the power bank module and use something like this:

5V 5A DC USB Buck Power Module USB Charging Board High Current Support QC3.0 | eBay

That power bank module you linked, probably is designed for only one cell in series
 
#45
My intention to use this was to get a way to charge my speaker from USB (and with QC3.0 even better!) and also get a small powerbank together with the speaker.
I plan to buy a booster and put after the batteries to step up the voltage from 3.7-4.2 to about 12v or a little bit higher.
So, my schematic to the Project was something like this:
Esquema_liga_o_coluna.png


My real question is if that connection from the cells to a BMS and the other side is possible/safe and will not confuse or broke the "powerbank" module (using this only to charge the cells and powerbank mode).
Thank you 🙂
 
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#46
Remember that the current demand increases when stepping the voltage up. You may end up with the capacity of just one battery, being you will be stepping the voltage up around 4 times..


Perhaps use the booster board to charge a 12 volt battery?
 
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#48
I was thinking simplicity and less chances for noise. I'll apologize for I haven't covered the whole thread but for what I see, you're stepping ~3.7 volts up to ~12 volts. Being your Bluetooth unit and the amp operate with 12 volts, why not use a battery already at 12 volts with cell protection built in..


I believe I understand correctly that you plan to charge from a 5 volt source? The step up buck converter could charge a 12 volt battery from a 5 volt source. The battery that I'm thinking of only needs 1 amp charge BUT the voltage needs to be close to 12.6 volts as possible. I didn't go look at your buck converter but is the output voltage adjustable or fixed?


This is the style of battery I refer to. I use lots of them. Very nice units and never had one fail..


GTF 20000mAh Lithium Ion High Capacity Rechargeable Battery AC Power Charger With 4 kinds of Plugs Promotion Drop Shipping-in Rechargeable Batteries from Consumer Electronics on Aliexpress.com | Alibaba Group
 
#49
I looked at the charge protection board that you linked to. The batteries are connected in series, which is 14.8 volts. A sense wire connects to each cell to monitor the voltage during charge..


*Correction on the buck converter..
Input voltage: DC12-36V


Output.. 5 volts..
5V 5A DC USB Buck Power Module USB Charging Board High Current Support QC3.0 | eBay


I'm kinda lost now.. What is the reason for the "Step Up" unit?
 
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#55
EBay tpa3116 amp and a sure audio bluetooth module and done...make an enclosure for added coolness.
I used a large square lead acid rechargeable battery and the cabinet is based on a planet 10 micro fonken. Drivers are cheap tang band full range drivers and it sounds great for what it is.

An externally hosted image should be here but it was not working when we last tested it.

Sure Electronics AA-AB41136 Bluetooth 4.0 Audio Receiver Board aptX +EDR 12 VDC
Yuan-Jing TPA3116 Class D Amplifier Board 50W+50W
 
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#59
Hello, can someone please help me reduce the gain of the amplifier? I think this is 32dB gain according to TI.
In 25% of volume connected to my laptop, my technics speakers are really loud and I want to fix that.
So, R6 and R3 control the gain of the amplifier, I've read somewhere that I only need to remove one resistor in order to reduce the gain, is this true? Which one?
Is also possible to add a knob to control the input volume like some boards have?
Thank you.
IMG_0030.jpg
 
#60
Let me see if i can find some more...

Yes one of those square 12V lead acid rechargable batteries. Zero noise...since no charger is hooked up. I just take the batter out to charge it...the back is removable.

It is hooked up to both the amp and the BT module.

One charge can last for weeks with light use.

What amp is that? Is it a TPA3116?
 
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