Found this while searching for Walsh functions http://www.bobblick.com/bob/projects/mclock/index.html Nice... but it doesn't make a noise, except whirr-whirr. Regards, Tony Allgood Penrith, Cumbria, UK Walsh synthesiser, SuperLadder, TB303 clone and rack mounted filter http://www.techrepairs.freeserve.co.uk/projects.htm