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I'm trying to build a twin-T oscillator for synthesising drum sounds. The LM741 heats up pretty quickly and the circuit hardly oscillates even when the feedback is at 100 per cent. Even with an LM386 amp I hardly get anything (though I can see some oscillation on the scope). The circuit gets 10ms 5V pulses from an Arduino. Does the TL071/2 run from single supply? Can it replace the LM741?

Schematic_http://www.flickr.com/photos/alkopop79/8644385451/

Anindo Ghosh
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alkopop79
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  • Any op amp can run from a single supply.
  • It is difficult to tell what is actually being asked here. Please post a schematic.
    • – Matt Young Apr 13 '13 at 05:14
  • Schematics here: http://www.flickr.com/photos/alkopop79/8644385451/ – alkopop79 Apr 13 '13 at 12:09
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    I suspect a capacitor in series with the output would improve behaviour - at the moment it's effectively DC-coupled the output to ground. – pjc50 Apr 13 '13 at 12:49
  • What is the power supply voltage being used? – Anindo Ghosh Apr 13 '13 at 12:54
  • https://www.circuitlab.com/browse/by-tag/drum/
    Your output loads your (-) feedback loop.     – Optionparty Apr 13 '13 at 14:31
  • The power supply is 9V. I suspect the lack of virtual ground won't help the 741. – alkopop79 Apr 13 '13 at 14:54
  • Optionparty, the feedback is necessary to create oscillation. Further simulation revealed that the circuit won't work (i.e. won't oscillate) without virtual ground. I guess I need to build a rail splitter. Still, are there op amps that do not need virtual ground? – alkopop79 Apr 13 '13 at 15:18
  • Here's a link of the circuit click here , feel free to simulate it (Open in editor. – alkopop79 Apr 13 '13 at 15:20
  • @alkopop79 Keep in mind that the LM386 is not an operational amplifier - it's a small audio power amp. It generally won't work in standard op-amp circuits as a "drop in" replacement without modification of the ciruit. – MattyZ May 14 '13 at 22:30