I saw a picture of a GG 3-400Z tube amp with two 47 ohm thermistors in series. In parallel with them was a coil of #14 wire 1 1/4 inch in diamter at 2 TPI. How does this type of Parasitic Supressor operate? 73, Bill ===== Bill Smith KO4NR __________________________________________________ Do You Yahoo!? Yahoo! Tax Center - online filing with TurboTax http://taxes.yahoo.com/