The TDA7293MOD is the Modular version of the TDA7293 amp. As can be seen in the diagram below, two TDA7293 amps are used. One as the Master, the other as Slave. In this arrangement, only the power mosfets in the Slave are used. It is equivalent to doubling the number of power mosfets. Only the TDA7293 has this feature, not the LM3875. 

What do I get with this. Well, plenty. With two TDA7293 running at +-40V, the power output is about 80 Watts into 4 ohms. This is far greater than using one TDA7293. And this is clean power. Before clip. Not some nonsense like 10% THD. Power into 8 ohms remains at 60 Watts. With such high power, the TDA7293 is into the realm of discrete amplifiers.

TDA7293MOD pcb

In the pcb above, the Master TDA7293 is on the left. To the right is the Slave. In front of the Slave unit is a discrete buffer. This will isolate the Master TDA7293 from whatever is before it. In other words, it is safe to install a potentiometer if desired. It will not “load” the input of the Master TDA7293.

The TDA7293MOD pcb measures only 3-3/4″ x 2-1/2″. To accommodate this small footprint, there’s simply no space for the power supply caps. In view of the higher power output, the TDA7293MOD deserves a decent power supply. I am contemplating a PSU board of about 20,000uF. Nice and beefy. A bit of an overkill but this is DIY. We don’t have to cut corners.