op amp741 & low voltage power amp 386
hi,
are you using the 741 as mike pre-amp and the 386 as your power amp?
here's the pin assignment of those ic
741 1. offset null 386 1. gain
2. inv. input 2. inv. input
3. non-inv. input 3. non-inv. input
4. Vss 4, gnd
5. offset null 5. output
6. output 6. V+
7. Vcc 7. Bypass
8. open 8. gain
pls. take note that the 741 is a dual supply ic and the 386 as a single supply. are you operating the 741 on a single supply manner?
since you have not posted the schem of your project its quite hard to give you solutions to your problem although the circuitry used for this kind of devices are quite simple.
the problem could probably lie in the construction of your project.
the 386 is internally set to have a gain of 20, if you want to increase the gain say 200 you can place an electrolytic cap of 10uf/16v across pin 1 and 8 with the positive (+) terminal of the cap at pin 1.
as to the 741 theres a feedback network in your circuit. heres a formula use can use to check the gain set of your project.
for an input at pin 2 (inv. in) Gain = Feedback Resistor/ Input resistor
for an input at pin 3 (non-inv. in.) Gain = 1 + (Rf/Rin)
if you want to increase the gain say 200 you can retain the input resistor (Rin) and mutiply if by 200 and that product is your feedback resistor (Rf)
hope this can solve your problem. :wink: