This time a capsule swap in a pair of MXL 990s.

First question is how to mount them. I forgot to order a mounting saddle, so a bit of audio improvisation...  Scrounging in the garage came up with a PVC pipe flange 1” inside dia. Five minutes later with a pair of tin snips and a drill, we have a coupla quick and dirty saddles. Well, clean actually, but you know what I mean.

It’s simply attached to the old post with the screw that held the original capsule holder. A piece of solid wire wrapped around it holds the capsule firmly. It won’t likely survive being shot from a cannon or shipped UPS, but it suffices for my purposes. If this is worth making permanent, I’ll do it right later.

Solder the wire from the front diaphragm to the input and connect the backplate wire to ground in place of the originals, and the basic swap is done. An hour later the second one is finished.

The rear diaphragm is left unconnected, so we should have a cardioid pattern.

Next they went into the multi-million dollar audioimprov pseudo-anechoic chamber for a quick test. Somewhat to my surprise, sensitivity is down a tad. I had expected it to rise. Perhaps the polarizing supply needs a boost? Hmmm...

Here’s a quick frequency response graph. Not too bad. The pair are not a real close match, but they don’t sound bad on a quick voice check.

More to come. F’rinstance, differences between front and rear diaphragms, and which is the “front” anyway? Omni pattern using both sides? Actually recording with them?