WEEKLY TIP: BEWARE THE DECEIVING CRYSTAL...

You've heard of "sending the wrong message"? CRYSTAL ELEMENTS can do this...

I recently had the occasion to work on a lovely original SHURE 707A, complete with its R7 crystal element. Upon extracting the R7 from the mic's grill, disconnecting it for testing, and fitting it with alligator clip-equipped test leads, I gave the element a succession of light tabs. BOOM BOOM BOOM went the amplified signal from the legendary crystal. Wow, sez I, this baby's got loads of output! And then, "Test test test..." Absolute silence. No output with the verbal test. Repeat procedures, same results. Huh...
Let this WEEKLY TIP be a warning: If you're shopping for vintage crystal elements or the mics that contain them, don't settle for a simple "tap test" to assure the element in question is operational. The Rochelle salt crystals within can develop fractures that will allow signal generated by impact to pass yet NOT possess the continuity to allow soundwaves to be collected and transmitted. Very deceiving...