Ive got a 4" sniper coil and that seems to be working ok. Ive also taken the garret extension for the 1/4" and connected the factor phones to the garret headphone connector. Seems to be working ok with the sniper. Might be the large coil. Ive unwrapped the coil cable from the detector altogether and nothing, not a sound. The detector is fired up ready to convey a signal, but pass a penny or any other coin past it and not a thing. I havent yet, but my son has an AT Gold so might try his large coil on the detector. That'll tell me if its the coil or not........same size coil. Anyway thanks for all your suggestions. I'll let you know how I go.