|The Quad coil would only adjust the video buzz from the audio. If you are now saying you have some audio beating in the video, might be the tuner oscillator is off a little. Check the tubes in the tuner, if good might just rock the tuners oscillator some and see if that clears it up. The I.F. could cause this as well. May check all the I.F. tubes while you are at it. If all those tubes are good, may rock the last I.F. a little see if that does it. Be careful if you rock any of the other I.F. cans, as you could make matters worse. A sweep alignment would be a good thing if you have a marker generator.