TPA7297 build

[Magnitude]

TDA7297 build

Good morning, or whenever you may read this I guess..

I want to put together a portable TDA7297 bluetooth speaker system and am looking for a little advice. I have the board now and I am really impressed with it over my old Pam8403 board. I am currently powering it with a step-up usb cable that delivers 12v @ 700mA. I am going to switch over to a 12v lithium battery that provides 12v @ 2A. I am pretty sure that I have decided on 4x Faital Pro 3Fe22 drivers based on their good reviews and light weight.

So my questions are as follows.

1. I have read the 3Fe22 drivers distort with frequencies much below 200Hz. Is there a crossover I can use for this build and send my low frequencies to a small subwoofer? Would this even make sense?

2. There are a few mods out there for this board such as replacing the capacitors, removing the mute, AC diode etc. In anyone experience are these worth it and if so can you make a suggestion?

Thank you in advance for any info you can provide.

 

[chermann]

Hi Magnitude


a pic of your board would be nice.


in the datasheet :
the chip is a entrylevel power chip. the TDA7297 chip can handle +/- 18V so your choice of 12V is ok. the psu with 12V/2A is good for that but you need a good decoupling cap for the dynamic peaks -lets look at your board. in the datasheet all diagramm and references are for 8R impdance -so with 4R speakers you might get more distortions and get very fast in the heat protection of the chip

i have a board and its single supply-
DROK(R) Mini Verstarker Powered Stereo: Amazon.de: Elektronik


that means you have about 6V for both half of the sine wave (the amp/setting is centered in the middle)

the current of the chip is 2A peak so about 1,4 rms (..constant) <---> the speakers are 4ohm impedance and thats very closed to the max - it will get hot. do not use 2 speakers in parallel.

with 6V supply at one speaker (4R) you get about 4,5 Watt ! and a current of 1,06 amps - each channel !

so my proposal for using this amp is try to mount a bigger heat sink
%product-title% kaufen

have fun
chris

 

[Magnitude]

Thank you very much for the reply.

Here is the board, it is the same one that you posted.

https://www.amazon.ca/DROK-TDA7297-...s=tda7297&qid=1574889926&s=electronics&sr=1-1


Here are the speakers, they are 8ohm
FaitalPRO 3FE22 3" Neodymium Professional Full-Range Woofer 8 Ohm

I was going to mount a bigger heat sink for sure. I noticed it getting very hot even running off the usb cable so I was going to use the one from my old CPU and adapt it to fit the chip.

I know how to follow a schematic so I have made a few projects, however, I have little idea how to modify or design circuits. What sort of decoupling cap and how exactly would I attach it to the board. Excuse the ignorance, I am new actually trying to understand what I am soldering and why.

 

[Magnitude]

I also found this crossover that seems to meet my needs. Can I use this to add a subwoofer in?

Subwoofer Crossover 8 Ohm 150 Hz 200W

 

[stratus46]

Good morning, or whenever you may read this I guess..

I want to put together a portable TDA7297 bluetooth speaker system and am looking for a little advice. I have the board now and I am really impressed with it over my old Pam8403 board. I am currently powering it with a step-up usb cable that delivers 12v @ 700mA. I am going to switch over to a 12v lithium battery that provides 12v @ 2A. I am pretty sure that I have decided on 4x Faital Pro 3Fe22 drivers based on their good reviews and light weight.

So my questions are as follows.

1. I have read the 3Fe22 drivers distort with frequencies much below 200Hz. Is there a crossover I can use for this build and send my low frequencies to a small subwoofer? Would this even make sense?

2. There are a few mods out there for this board such as replacing the capacitors, removing the mute, AC diode etc. In anyone experience are these worth it and if so can you make a suggestion?

Thank you in advance for any info you can provide.

Have you looked into class D amplifiers like the TPA3116 or TDA7492? On batteries I would
think maximum efficiency would be very important. It improves battery life and minimizes
power dissipation in the amplifier chip. Less heatsink, less weight.

Active crossover would include a summing amp and LP filter for the sub and could be done
with a dual opamp and single ended supply pretty easily and then high pass opamps for the
L and R channels. Reduces your distortion problem and unneeded power to L and R for better
battery life.

G²

 

[chermann]

Hi


Good point by stratus46 -->- i over read the portable usage! so take a look for this amps - class D are very nice because of less power consumption.


for the TDA7297 - i would´t change something. this chip is good to have fun but not for "serious" hifi usage at home in the listening room.
yes it gets hot - look at the figure 9 at the datasheet.
decoupling caps are the caps to stabilse the voltage at the supply pins of the chip. often the chinese amps use old, used or fake caps -
original TDA chip can handle short circuit at the outputs - so you can try to shorten it to be sure you get a good one - but be aware if you do this with a fake part the chip will die!! and the supply gets sorted - so please use a 2Afuse "fast" - at your supply for testing.


speaker:
yes this are 8 ohms - fine - i just type in for searching and i get all versions in 4 R. its normal that a mid/high spekaer do not want to handle low frequencies - so using of a filter will help the chassis during playing --> less distrtion as stratus46 wrote.


chris

 

[Magnitude]

I have looked at the class D amplifiers and decided to go with the one I chose based on sound quality from various comparison videos that I watched. While they are supposed to be portable I don't mean the equivalent of a small bluetooth speaker, but just something that I can power with a reasonable battery pack. I don't mind the increased battery consumption if I can get a better sound. Not much to throw an extra battery in the pack for an overnight camping in the back country.

So, I am understanding that I should replace the 2 capacitors that are shown at the Vcc? If those caps are often bad, should I just de-solder the chip and go point to point with new audio caps and resistors? I know it will never be an amazing amp, just want to do what I can to get the best sound I can from a battery powered amplifier.

Thanks again

 

[Yatsushiro]

I have looked at the class D amplifiers and decided to go with the one I chose based on sound quality from various comparison videos that I watched.

The TDA7297 can be made to sound very good indeed; this is a good first step:

TDA7297 Build Guide V.2 **Updated SG Change**

 

[chermann]

oh... i dont know that link..


thx
chris

 

[Magnitude]

I received my 12v-2A power supply yesterday. Real improvement over the 12v-700mA step-up cable.

However, As per our discussion regarding the new heat sink.

Running this board off this power supply connected to 4- 8 ohm speakers in parallel will trip the thermal protection with the original heat sink as it gets scorching hot when not even turned up all the way.

 

[chermann]

Heat dissapation_ AB chips

Hi Magnitude


Have a closer look to the data sheet at figure 9. at - look at e.g. 0,5Watt output - with correct heat sink - you get about with 6 Watt heat dissapation !!! note the graph shows 16,5Vcc - you´r using now 12V - the original heat sink is bad. --> so a 2,3K/W or bigger should do.
at the max ratings is written that the case temp is max. 70°C - so with a bid of margin you should n´t measure at the case about 60-65°C max!! during your power tests - be carefully here....
also wriiten at the max ratings:
the max peak current is 2A (--->rms - continious 1,414A), if you use a good DMM at a resistive load of 8R - you should have less then U = I*R = 1,4 *8= 11,3Volts measured at the load. - lets say 10V - make a mark at the volume knob or your setting at your source.


chris

 

[nguyenthachung]

hello! I want to simulate tda 7297 amplifier circuit using multisim but its library does not contain tda7297
Can anyone help me to solve this problem.