Mark, Radio Shack part number 32-1031. They are $7 a piece. Get two of them and wire them so you go from 8 ohms to high impedance and then back to 8 ohms. Carl Moreschi 919-676-1991 x135 -- Original
One note of caution - if you use a linear amp with a big power transformer in an aluminum chassis (read: any current Alpha, Ten-Tec, etc.) keep the audio isolation xfmr away from the linear's power t