Thanks Paul I found a circuit at a site called "Circuit Central" http://209.75.211.230/cc/index.htm But I don't think I understand it. It has three points, two labled eiter "V5" or "Vs", not sure which. And another labled "+V5/2" or "+Vs/2" Can anyone help? I don't mind a little noise. Mark -- Mark & Carlyn Grocholski MOZEPY Productions ><> www.earthlink.net/~mozepy