Mark Rages wrote: > (Olin: the circuit was attached to the first message. Scroll back in > your threaded MUA and you'll see it.) Yeah, right. I'm supposed to keep old PIClist messages on various machines I'm on, and then dig them out and refer back to them to give free help? Think again. > What op-amp are you using? But that was listed on the circuit he posted. I guess you don't keep old messages either. If I remember right the opamp was a 741. It's not a great choice for noise and supply headroom, but should work for the sound trigger the OP was trying to make. I don't think the opamp is his problem assuming it has sufficient supply voltage and headroom. ****************************************************************** Embed Inc, Littleton Massachusetts, (978) 742-9014. #1 PIC consultant in 2004 program year. http://www.embedinc.com/products -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist