Hand-match your resistors using a DVM. Sort through a bunch and find the closest you can, then trim up as needed. You can usually do 1% or better in a given lot of 5% resistors. -- Feel the power of the dark side! Atmel AVR -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist