TDA7375 as a subwoofer amp

[JAZZ2250]

I'm thinking to try TDA7375 as a subwoofer amplifier. This chip works on a single power supply. It has four inputs and outputs which can be bridged resulting in 2 inputs and outputs. I have tried this chip in bridged mode with 12V supply for a home use, and I'm satisfied with the sound.
My question is "how I can make a low pass crossover for a subwoofer application (for car and/or home use)" A simple RC filter in front of the input will work? Or, do I need to make an active crossover using TI opamps? I want to keep the supply voltage of 12V. Any kind of comment would be appreciated. Thanks.

 

[JAZZ2250]

diagram

Attached is a diagram from the datasheet showing a bridged mode application.

 

[hdoggz]

I'm thinking about doing a similar project witha TDA7294. I got a pair of these chips from an old Sony stereo I bought used for $5. we ought to compare notes though. Do you plan on laying out a board? how big of a heat sink are you planning on using?

 

[Evan Shultz]

It depends on your application. A simple RC filter will remove high frequencies, but it will neither remove them quickly or greatly reduce them. I suggest you use an active filter. This will not only give you at least a second order filter but it will also give you a stable input impedance to the amp. If you only want to use a single 12V supply it is easy enough to run the op amp from 12V and ground and bias the audio around 6V using a simple resistice divider. Make sure you DC couple the input and output of the filter. TI provides a program called FilterPro on their website that will get you schematics and component values. I would suggest an 80-100Hz crossover frequency, at least to start out with. You may want to tweak it later after you build it and listen.

 

[Gasho]

Jazz 2550, is that Stevie Ray on your avatar.

I am not shure that chip amps of any kind , have output current for controling a sub drive units.

 

[hi_im_sean]

Ive seen chip amp used in many things before, but rarely for a sub application. I took apart a small 35W harmon Kardon sub, that had a chip amp in it, but thats the only one ive ver seen. I have not had good experience as far as reliability and sound quality even above 100Hz with chip amps, i would not recommend using chip amps at all, but especially for a sub. they simply dont have the power capabilities and sufficient output current, go discrete.