1
\$\begingroup\$

I'm working on a project where I'm controlling a Yamaha YM2612 with an Arduino MEGA. I can communicate with the chip just fine, but I'm having problems with the audio signal the chip is outputting. I'm running the signal to an audio op amp module to boost the signal the chip outputs, but there's a lot of noise in the signal. I've listened to the output of the module without the chip on and it's very very clean, so I'm sure there's something I'm not doing right in my circuit. I've tried other 2612 chips I have but the noise seems to be the same.

Details: Circuit is on a breadboard

Arduino MEGA is using USB power

YM2612 clock signal generated from Arduino MEGA

YM2612 "datasheet" https://datasheetspdf.com/pdf-file/865751/Yamaha/YM2612/1

breadboard circuit schematic https://gyazo.com/f2d06e9e316e6bbcc85c20f805142bb4

\$\endgroup\$

2 Answers 2

Reset to default
1
\$\begingroup\$

My pc never heard of your OOG file type so I could not play your sounds. The wires and rows of contacts all over the place on a breadboard guarantees hum and other interference. The LM386 is a cheap Power amplifier with noise, not a low noise opamp. Your circuit is wrong, you should have looked at the datasheet. enter image description here

\$\endgroup\$
0
\$\begingroup\$

Maybe (probably?) the noise is from the "toy" LM386 module but you do not show its schematic and wiring (a breadboard might cause it to oscillate).

\$\endgroup\$
4
  • \$\begingroup\$ I can't show the schematic for it because I don't know what it is and there isn't any way to do so unless you probe the circuit out. It only has 3 inputs (audio signal, V+, and V-). I've tried using both (5v & 0v) as well as +/-9v for the module and it doesn't seem to make any difference in the audio output. Probing the audio signal between the chip and the lm386 shows a lot of noise before it even enters the chip. It makes the trace fairly blurry. \$\endgroup\$
    – TokyoScarab
    Aug 23, 2018 at 6:15
  • \$\begingroup\$ Here is a recording of the chip playing a single note set to a sine wave. drive.google.com/open?id=1DJvdio4_7wYGGdHMkTd9JLb1RSsZNCi- \$\endgroup\$
    – TokyoScarab
    Aug 23, 2018 at 6:24
  • \$\begingroup\$ I was able to remove the noise. It's amazing what you can do after some power filtering / bypassing lol I was able to find a schematic for this module after some digging around. gyazo.com/db86a49d0b6da6b224338c77534bc490 \$\endgroup\$
    – TokyoScarab
    Aug 25, 2018 at 17:25
  • \$\begingroup\$ @TokyoScarab - "I was able to remove the noise" Great! Can you please write an answer explaining exactly what you did? Then you can "accept" your own answer, which will tell the website that the problem has been solved. Thanks. \$\endgroup\$
    – SamGibson ♦
    Aug 29, 2018 at 1:47

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.