Hey Guys,

I got a cheap car stereo from eBay (JDS-520) and after inspecting the internals I quickly came to realize that the advertised 60w x4 was a load of crap haha. the audio amp inside was a TDA7385 which after looking through the datasheet I found it is capable of 30w x4, not only that most of the capacitors used in the device didn't match up to the datasheet at all, the biggest difference being that the 1000uf cap used on the VCC was meant to be 2200uf. anyway, I changed out all the caps to the desired values, and then it got me thinking. i had an old stereo laying around that can output at 50w and after looking through the datasheet for the TB2910HQ I have laying around it seems that all the pinout match up completely. the only difference being this new chip has an i2c bus and the other doesn't. will this still work if i just swap them?
i understand more cooling would be needed but I'm confident that there is plenty of material available to still passively cool off the case.

 

What does the I2C do?

If it is to control the amp then you're out of luck.

 

The Volume control is done by the I2C pin, serial data..


https://www.mahachaielectronics.com/product/1050/tb2910hq-zip-25

 

The "load of crap" is that severe distortion produces additional output power. Then ignorant people who do not notice the distortion think it is a little louder.

The original TSA7385 produces 30 Whats with a very high supply voltage and very high distortion, or 14 Watts per channel into 4 ohms with a normal 14.4V charging car battery and at fairly low distortion, like most car radios.
The TB2910HQ IC produces slightly more power that you will not notice but it can drive 2 ohm speakers with 24 Watts per channel at low distortion. Even with the replacement IC and with 2 ohm speakers the increase in low distortion loudness is almost nothing, don't bother with it.

With a 60V power supply, a TDA7294 amplifier IC can produce 80 watts per channel at fairly low distortion. You will notice the increased loudness if you turn up the volume.