Hi... I came across your site / example for building a class b audio amplifier.

I don't have (6) 6v batteries... Can I use a single 12v battery? If so, can you tell me what modifications i would have to make to have it work?

I am particularly interested in this circuit because I bought a cheap head-phone FM radio and want to output the audio through this amp...

Lastly, it the output noticeable (e.g., loud) - or just so-so...

 

You can use a 12V battery and a LM7806 voltage regulator. Apart from a 0.1uF tantalum capacitor at the output (as recommended in the datasheet), you don't need to use more components.

 

Take the "ground" from the LM7806 output, and use take the "-6V" from battery negative.

 

Ok... But just to clarrify - why the voltage regulator?

I initially put (+) to 8, (+) to 5, and (-) to 4... Is that right?

Lastly, I am particularly concerned if the output will be LOUD - easily heard across the room - right?

If not, how do I boost the output?

 

Pin 5 of the chip, the non-inverting i/p of amp B, must be connected to ground, not +. Ground is established by the voltage regulator.

It would, of course, be easier to use two batteries as suggested in the text.

 

Ok... I'll try it out...