MS Mic Construction
Phantom XY ConstructionFigure 8 & Blumlein
Nifty Circuits
Mic Links and Parts Sources
MS Mic Construction
Phantom XY Construction
Nifty Circuits
Mic Links and Parts Sources
| The basic capsule modification involves cutting the connection between terminal 2, which is connected to the source terminal of the capsule's internal FET, and the case of the capsule. An X-acto knife is perfect for this. The WM-61 only has one trace to cut; the WM-55 has three. Check with an ohmmeter to make sure the traces have been severed. |
| Since all of these projects involve an array of mic capsules, it makes sense to make the mounting clips also function as the ground connection. I used paper clip wire to fashion the clips because they are easy to bend, easy to solder, and easy to find. Although the clips hold the capsules pretty securely and make a good electrical connection, I put a bead of silver-bearing conductive epoxy over the paper-clip wire to make a more secure mount and provide an electrical connection that prevents oxidization of the aluminum capsule cases. |
| The Linkwitz mod is used to convert the electret capsule from its normal configuration where the FET is operated in common source mode to one where the FET is operated in source follower mode. This enables the capsule to operate at far higher SPL levels and is far more linear due to the degeneration across the source resistor. In the 3 wire version, the source, drain, and case connections are brought out separately. In the 2 wire version, terminal 1 (the drain of the internal FET) is connected to the case with a drop of conductive paint. The Linkwitz mod is named after its inventor, Sigfried Linkwitz, a noted speaker designer and co-inventor of the famed Linkwitz-Riley speaker crossover. |
