Methods and apparatus to perform hard-disk drive head proximity detection in a preamplifier are described. The demodulation section 13 includes a frequency deviation compensation section and a carrier recovery section each having a loop filter 14 with three or more stages of time constants. No roll-back deformation of a flanged portion occurs when integrally vulcanize adhering the cup piece to the rubber elastic body, and also when imparting pre-compression to the rubber elastic body by diameter widening a tubular portion of the cup piece. The invention also includes a timepiece, such as a mechanical watch, comprising such a gong.