hello guys i've built this simple amp, it consist in a lm358n driving a pure class B push-pull and it's getting a negative feedback by a 220Ω resistor, the question is: is it scalable to high power?

currently is running from a 5 v battery pack (2.5v ±), in the schematic i've put a 5v regulated (positive and negative) supply for the lm358n and i've increased the voltage to the push pull, but still there is a problem, the feedback get's higher, so i have to increase the resistor (and of course put more power transistor)

if i do all that things will it increase the output power? and any ideas on how to stabilize it, cuz sometimes when i plug it in on my mp3 it sounds bad and i have to short the input with the ground and plug back in the mp3 and the works fine, it's like a "reset", a thing that i want to get rid off.

-Francesco

 

Please, post schematics in PDF or JPG format.

 

NO! This is not scalable for higher power.

If you want more power than just a watt or two, go buy a LM3886 kit, that gives you 60 watts in 4 ohms which is plenty.

 

Hello,

There are a couple of nice audio amplifier projects in "the completed projects" forum.
Take a look in it's index:
Completed Projects Index

Bertus

 

i've attached the amp that i made to a 18v ± and it gives out more power, i'll try a darlington pair to archive more gain, beacause that poor lm358n is driving directly 2 power transistors (d688 and d718)