1
\$\begingroup\$

I am getting pretty tired of debugging the LM386 integration into my project! I'm building a drum machine, based around schmnitt trigger oscilators and a white noise generator. I'd post the complete schematic, but its getting complicated, and everything works accept this part - the audio output.

When I tap the output of my device and plug it into a battery-powered guitar amp I have on my desk, everything is great, I'm done. BUT I want my project to also have a built in speaker. I've used LM386 for tons of synthesizer stuff like this before, but this one just ain't happening. I'm getting wild oscillations, sometimes no sound at all, sometimes only part of the sound (like the "kick" but not the "snare"). I've tried decoupling capacitors in series, on the power-pins, and zobel network.

TL;DR - Can anyone recommend an easy replacement for the LM386. A 9V powered IC that can drive a speaker. THANKS!

enter image description here

\$\endgroup\$

3 Answers 3

Reset to default
2
\$\begingroup\$

You might try the TDA7050 (5V) or TDA7052 (18V max). Both are bridge amplifiers, so they don't require a large speaker coupling capacitor. And they don't require a load cell / boucherot network either (R+C parallel to the speaker).

\$\endgroup\$
1
  • 1
    \$\begingroup\$ Checked as answer because other users offered good advice and criticism, but "TDA7050" is actually an answer to my question Thanks! \$\endgroup\$
    – pinhead
    Jul 12, 2014 at 2:39
4
\$\begingroup\$

The LM386 seems to be a appropriate chip for this application, so there is no need for a replacement. If you can't get it to work, the problem is in you circuit. Since you haven't shown us your circuit, there is little more than can be said.

Whatever you are doing wrong would be just as likely to happen to a replacement part.

It might be useful to test out just the power amp part with the LM386 by itself. Once you get that working, you can incorporate the successful circuit into your larger project.

\$\endgroup\$
1
  • 1
    \$\begingroup\$ Ha, Ok the forum has spoken... back to the drawing (bread) board. Thanks! \$\endgroup\$
    – pinhead
    Jun 30, 2014 at 23:02
2
\$\begingroup\$

Note that wired breadboards can have good power distribution but could just as likely have bad power distribution.

Any component that has gain and a possibility of feedback could oscillate if not properly compensated and properly wired up to its power source.

You could also have problems if your Schmidt trigger oscillators coupling into the gain element in ways that are not friendly to the normal operation of the LM386.

One question back to you is to wonder if the oscillators on your board have screaming fast edges that translate to high frequencies?

\$\endgroup\$
1
  • 1
    \$\begingroup\$ Not sure how to answer that question - the oscillators are square waves, so the edges are fast...? They output audio frequencies though - one at 1-3 kHz, the other at 60-180 Hz. And I have power decoupling capacitors right on the hot pin of each of those chips - I used to get interference from them before I put those caps in \$\endgroup\$
    – pinhead
    Jul 1, 2014 at 16:01

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge that you have read and understand our privacy policy and code of conduct.

Not the answer you're looking for? Browse other questions tagged or ask your own question.