I recently purchased a used Masterbilt EF-500RCCE from MF. I absolutely love this guitar BUT there's a strange springy rattle when the open B string is played, or when ever any B is played. This really stands out when playing the second string 12th fret harmonic.
Anyway, I found that when I plugged into the Nanomag jack the rattling stopped. I pulled the jack out to have a look and found that when I tapped on the side of the jack with my fingernail I could hear the springy rattle. Unfortunately this isn't a simple jack. It appears to be some type of mono dual switching jack (See below):
My questions are:
1. Has anyone else reported this problem with the EF-500RCCE?
2. If I stick a plug into the Nanomag jack to stop this rattle, will it drain the battery?
3. Can this be replaced with a simple single switchjack? (i.e. does the output wire to the 'mix out' jack have to be grounded when the NanoMag jack is used?.
BTW- this jack has 'CHUNGSEN' stamped on the surface of the plastic casing.