Another Harp Mic Project

[jjasilli]

Vintage Shure Bullet Mic

[Willabe]

Could you elaborate on what your doing/going for on this please? (Adding a volume control?)


              Brad   

[jjasilli]

This is a vintage Shure bullet mic; specs stated in first post & schematic.  Tested the voice coil on a DVM and got a reading in the ballpark per internet research.  The point was to ready it for performance as a harp mic into a tube guitar amp.  The bullet body has two holes in the bottom: mid & rear.  The rear hole accepts a signal cable.  So I permanently attached a 2-conductor mic cable.  The cable has zip ties inside and outside the mic body to serve as strain reliefs.


The mid-bottom hole in the mic body is to screw the mic to a stand; but a stand isn't needed for a harp mic.  The hole happens to accept a mini pot, so  installed a vol. control there.  The new issue Shure bullet mic's for harp have this feature.  This enables to player to adjust or kill the mic signal w/o having to reach for the amp.


The voice coil is hi impedance and lo output at 1.1K DC resistance.  (For comparison:  a vintage single coil Strat is about 4K; humbuckers 8K)  So, ambient noise could be an issue.  To reduce noise, I used a 2 conductor mic cable, so all signal, + & ground, are in internal leads, shielded by the outer braid.  The outer braid also functions as the chassis connection between the amp & mic body. 

[jjasilli]

Interesting specs at the Shure Microphones Website.  for The 520SL   Cool, thanks; didn't think to look there!!!

[Willabe]

The point was to ready it for performance as a harp mic into a tube guitar amp.  The bullet body has two holes in the bottom: mid & rear.  The mid-bottom hole in the mic body is to screw the mic to a stand; but a stand isn't needed for a harp mic.  The hole happens to accept a mini pot, so  installed a vol. control there.

Ok, now I see, thanks JJ.



                  Brad