Microphone Choices: NITS and CHIGGERS: THE NASTY DETAILS INSIDE!
by Fritz Hasenpusch
Patients make their way to the MIC DUNGEON for all manner of reasons, for all manner of treatments. Just like with people, microphones can be affected by many different types of maladies that can adversely influence their looks, their viability, and their functional capability. Since we’ll be studying the “nasty details inside,” let’s assume we’ll be passing on the purely cosmetic fixes (no Kardashians) and dig into ways of actually maximizing your mic’s capability to deliver what you’re looking for: BETTER PERFORMANCE from your harpmic.
Topping the list of upcoming focus and features during our last visit to THE MIC BENCH was SWAPPING ELEMENTS AND POTENTIOMETER VALUES. What I’m referring to is the need to make certain your mic’s Element—the microphonic component in your harp mic—has a properly matched volume control installed (if you’re using one). How often I’ve opened-up a mic to find that the element’s been swapped-out, but the old V/C’s still on board—and the owner’s wondering why his audio expectations have not been realized.
First, the GOOD NEWS: Say you have a current issue SHURE 520 DX equipped with the stock R198 dynamic element and you’d like to replace it with a SHURE Controlled-Magnetic or Controlled-Reluctance element. The GOOD NEWS is that the 100K potentiometer that came with the 520DX will work just fine with any of the CM or CR elements.
The original 520DX shell, element, and little square pot are shown below along with candidate CM’s and CR’s and a variety of alternate 100K pots.
KINDA GOOD NEWS: One of the most common crossbreeds in the HARPMIC KINGDOM is the installation of the durable SHURE CM/CR element into the ASTATIC JT-30 / HOHNER BLUES BLASTER shell, replacing the often failed original. It’s an easy fit into a fractionally smaller mic body—BUT NOT a direct swap. The ASTATIC elements (shown as the four discs on the right in the picture below along with two comparable SHURE R7 elements to their left), being Crystal or Ceramic, need to “see” a considerably higher impedance than the SHURE CM and CR elements in order to function properly—at least ten times higher!
Thus, a suitable 100K pot will be needed to replace the 500K original found in the older BLUES BLASTERs or the 5MEG pot found in the newer JT-30 permutations equipped with the much smaller Japanese crystal (pictured below along with an earlier full-sized ASTATIC MC-151 crystal on the far right and an original BRUSH DEVELOPMENT CO.—originators of this technology—crystal element in the middle).
We’ll be looking into the Reverse Procedure, SWAPPING OUT FOR CRYSTAL!
THE NEXT TIME WE VISIT…
THE MIC BENCH
For pictures and descriptions of most of the microphones listed visit http://www.harmonicamasterclass.com/vintage_collection.htm