In a keyed-photocell electronic organ, two (or more) photocells are keyed with a single, make-break key switch via two (or more) respective RC keying or envelope-control circuits, one of which provides a transient keying pulse to a photocell in order to produce a chiff tone component. The chiff keying circuit includes a series capacitor, the output terminal of which is always clamped to ground by a diode circuit except for a short interval after the key switch is closed during which the level at the output terminal initially jumps and then falls off as the series capacitor charges.