I'm in the middle of building an amp using a basic LM386 with a 10uF cap on pins 1 and 8 to increase the volume. It's OK, in fact good, but I want that little bit more, so I got the LM386 n-4 IC which says it'll give me 1 watt. It doesn't give me any sound at all.
Before I cut out the cap and mess with something that does work, can anyone please tell me if that cap mod works on all versions of the 386, have got a dead chip, or am I missing something else?
Thanks
Denis
Replies
I just recently built 2 LM386n-4 boards and used a used 9 volt battery to test them. Both worked great. Each schematic was from the internet and used different values of caps and resistors. I set both up to give the 200 gain on pins 1 and 8. Plenty loud from the 8 volts I measured from the battery. I'll try 12 volts and see what it sounds like.
Richard
Denis, the 10uF capacitor between pins 1 & 8 are to increase gain, not volume. If you omit the capacitor, the preset gain of the 386 chip is 20. Using the capacitor increases gain to 200.
Voltage rating of the cap, if used, is typically 16v up to 35v. And it can be either radial or axial, and it should be polarized, with the + to pin 1, the - to pin 8.
But, as Paul and I have stated previously, the N4 version of the LM386 needs more power to operate.
Some time since this was brought up, but wanted to let you know that the 386N4 chip needs more voltage than the other 386 chips to work. The N1, N2 and N3 work on 9volt to 12volts while the N4 needs 14volts to18volts. That could be your problem if you were trying to run it on 9volts. Also the N4 chip can put out 2watts compaired to the others 1watt output.
The LM386 IC in all forms (N1, N3, N4) work in an amp circuit. The major difference is the input power supply ratings and power output.
If you have wired the LM386-N4 as shown on your schematic and you still get no sound, check all solder points and your grounds. Something physical is likely the problem.
With a maximum power source rating of 18vdc, you will need to power the amp with a fully regulated wall wart adapter, or figure a way of wiring two 9v in series, or twelve "AA" batteries...