Modding a PZM

Recently I wrote a post about mounting a pair of PZMs in the big room at KMS. They worked well, but the bass response just want quite would it could be. Opening them up I saw a capsule of questionable origin run thru a transformer of very dubious quality.

A google search revealed this schematic which allowed me to ditch the transformer and change some things around.

After a trip to Radio Shack I came back with a handful of capacitors, some zeener diodes and this capsule

RadioShack 270-090

I got out a breadboard, my soldering iron, glue gun, wire strippers, basically the regular gang of friends and went to work

So here’s the workspace ready to go

Soldering iron is on and heating up and I’ve placed the first capacitor in the breadboard

Here goes, inserting the rest of the caps, resistors, zeener diode and the leads for the mic element. I tried to lay this out in the most compact space I could

Now I’ve inserted the mic element and attached the mic cable for testing

Yay! It works, and no smoke when I hit the phantom power switch!

Time to gut the old PZM’s innards.

I chopped up the breadboard with some side cutters and made the circuit board as small as I could.

I got out the hot glue gun and cut the old foam to fit the new, larger capsule

Stick everything in the case, screw it together to look for shorts, flip the phantom power back on, test again and its ready to go!

And now its back where it belongs

“But, what was the point of all this?” You ask, in extreme aggravation waiting for all the photos to load

Well, see (or hear) for yourself:

First the unmodded PZM

And now the modded PZM

Listen for yourself. The modded PZM has WAY more bass response, more gain and less noise. Win win win all around!