Thanks Brian...
that solved a lot of confusion....
Hi Klaus,
Your advice prompted me to check the quiescent current of two commercial PA amplifiers, out of curiosity. That 20 Watt megaphone which I mentioned before consumes 70-80 mA of current at standby state. Usually we use it for a long day using 8 D cells at full sound power. Then I tested another amp of 30 W, that used a 12v 1.2 Ah battery and seems to drain out at a very fast rate. It consumes 250mA at standby state.
It seems 7377 is not obsolete like 7374. These ICs are popular around my local area rather than the TPA3116. I had this lying around for sometime and wished to do something with it. Anyway, I'll look out to see for any other chips available around here, that may perform better than the 7377.
Aby