Can someone tell me what the input impedance of the AF-1 is? I am looking for something to use with a Heathkit HW-8 which has about a 1K output impedance. I don't know what the impedance is, but the AF-1 works great with an HW-8. Also an HR-1661. In my experience, it's mandatory! 73 Eric WD6DBMSent from Yahoo Mail on Android