| Created by |
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| Created | March 23, 2013 |
| Last modified | March 23, 2013 |
| Tags | 555 drum oscillator pulse-generator synth twin-t |
555 pulse generator and Twin-T style oscillator for analog drum synthesizer.
Use 1/4 of LM324; use +12v for Vcc, and connect negative supply voltage to ground. A separate +5V supply is required for the drum oscillator.
Adjust "Q" until oscillation occurs, then back off just slightly. Output is on "sig" and should probably be buffered to refrain from affecting the rest of the circuit.
555 pulse generator input trig should be replaced with switch, uController, etc. C3 and R3 ensure that a short, sharp pulse is created regardless of how long the 555 trigger input is held low.
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I built this circuit with some modification on breadboard and it works well. However, I wonder what is the network of the diodes, R10 and C7 for? Does it increase the resonance? |
April 15, 2013 |
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This circuit is actually based on a kit from Paia: http://www.paia.com/ProdArticles/syndrum.htm Current through D2 and D3 causes the pitch to be higher than it would otherwise be. As C7 discharges, the voltage across the diodes decreases, and the pitch falls. You can use larger or smaller values of C7 (try double or half to start out with) to change the "fall time" of the pitch. |
April 15, 2013 |
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Fantastic! Thank you! |
April 15, 2013 |
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