low input gain level on tpa3116

[hormilo]

Hi,
I have just build a small portable box using tpa3116 2.1 board. It plays fantastic, but I am not getting enough power playing from phone (plays really loud over macbook-pro laptop).

I have actually two boards...both 3116...
Breeze Audio 2.1 high power HIFI digital power amplifier board TPA3116D2 beyond TPA3123 TDA2030 LM1875-in Amplifier from Consumer Electronics on Aliexpress.com | Alibaba Group

and this

TPA3116 2.1 CHANNEL Deluxe CLASS D amplifier board 2*50W+100W ASSEMBLED AND TESTED FREE SHIPPING-in Amplifier from Consumer Electronics on Aliexpress.com | Alibaba Group

both same low input gain.

So any idea how to fix this, since this speaker will be used primarily with phone?

Another thing...it's a 2.1 speaker, so just checking if anyone knows if this two boards are having crossover - low pass filter in sub-channel. As read from page..."the middle is a subwoofer frequency regulation"...so silver one from Breeze looks like it's there...not sure about red one?

Thanks in advance,
milos

 

[danzz]

The best an easiest way, would be to rise up the gain. Check the datasheet to see the valúes of the gain resistor setup and change them.

 

[hormilo]

the problem is that there were no datasheets with amps.

 

[JonSnell Electronic]

I would use a pre amp. There will be no low pass filters in the 2 - 1.

 

[irribeo]

Wiki here has gaintable for 3116 so does TI datasheet. Too easy? Go for preamp.

 

[erik777]

If you change the gain on pin 8 with higher ohm resistor. You might need to increase on the uf on the input caps per TI data sheet. My laptop measures at 800mv p/p.
The cellphone I can only imagine 100-150mv or there abouts

 

[brighter]

I also have the same issue with low gain on this board:
YJ HiFi TPA3116 2 1 CSR4 0 Bluetooth 4 0 Digital Amplifier Class D 100W 2 50W | eBay

Playing music via BT I'm geting mere 6w of music power @4ohm on l/r channels no mater input voltage of the supply. Tried several BT enabled devices with same results.
Sub channel on the other hand can be gained by sub potentiometer and also with master potentiometer.

Also, there I have this board:
TPA3116 2 1 Bluetooth Analog Input Amplifier Board Class D 100W 50 2 Amp | eBay

Same problem except here I can get around 16w music power @4ohm on l/r channels.
Sub channel is controled like the above board, only crossed lower.

So, my question is how can I add more gain if I have only basic soldering skills?
Btw, adding preamp, as someone suggests, would complicate things for this portable project...

Thanks in advance!

 

[Saturnus]

So, my question is how can I add more gain if I have only basic soldering skills?

If basic soldering skills means you can't find and reliably solder/desolder SMT components that are less than 1mm big on the largest size then you can't.

 

[brighter]

I guess that my basic soldering skills just advanced because I have done it! It was pretty easy job actually.
Resistor r1 20k replaced with 47k and resistor r2 100k replaced with 75k.
Now I have 36db gain instead of 20db! Yeiii!
Thanks!

 

[danzz]

Well done!!!....
Welcome to the amp modding world, carefull, ir can become an addiction!!!

 

[nijunge]

Hi sounds like you did it

I would love to see a picture and to know whitch of the board you like the most as im planning a build like yours and have looked at exactly those two options

What are your speaker design and does it work ;-)

Niels

 

[hifix]

Does it sound better with the increased gain ?

I guess that my basic soldering skills just advanced because I have done it! It was pretty easy job actually.
Resistor r1 20k replaced with 47k and resistor r2 100k replaced with 75k.
Now I have 36db gain instead of 20db! Yeiii!
Thanks!

 

[brighter]

Sorry for late reply, did'nt see any notice for Your reply...

Quality is the same, but one thing that started to be obvious after proper gaining is lack of good bass response! Measured it with dummy load on sub channel below 100hz and it has a very bad roll off! Thats YjHifi black box. I'm not using it since...

 

[Pafi]

The more the gain, the less the input impedance, so you need to change (or parallel) input caps also to higher value as Erik777 said.

 

[brighter]

I only modified l/r channels for maximum gain and actually I dont mind bass roll of there. Problem in fact is mono channel which is factory set for maximum gain and 1uF caps.

Bass mono channel always have cca -10db at 30hz even if I added 10uF in parrallel for each 3 on the left side. Maybe Im doing something wrong?