Cheap sub amp

[Davide82]

Hi!

I'm going to build an extremely simple sub amp.

I think it would be possible to use a low-power IC amp (like LM386) to drive a class B output stage. Any ideas?

I know this way I cannot have hi-fidelity but this amp handles no more than 150 Hz and I don't need a good quality; I just like to experiment!!

I would use this amp in a car, so I have plenty of current but only 12V. I may wire woofers achieving 1 or 2 ohm impedance in order to get enough power with only 12 V.

BYE!

[subwo1]

I suggest avoiding class B since with a little more effort you can have class AB. You can opt to bias it with at almost no idle current if you wish. At least the driver stage will not have to jump the gate voltages a lot in order to cross over from one output transistor to the other. One idea is to use two current sources to supply positive and negative bias to an IRF540/9540 pair. Place a capacitor from one gate to the other with the bias adjust components in between. Connect the output of the chip amp onto one of those capacitor leads. You should also use at least about 22 ohm gate resistors on each mosfet leading to each end of the capacitor.