The Preamp Detector combines a SERGE detector with a multi-purpose preamp suitable for a wide variety of inputs.
Sensitvity for the various audio sources can be adjusted over a very wide range using the preamp's GAIN control although it will not cut the gain to zero.

http://www.elby-designs.com/contents/en-us/p907_ES02.html

• ? mA +12V
• ? mA -12V
• ? mA 5V

Available as an assembled Module and as a DIY project.

No info about availability.