I found this on the k & k website on their trinity pro preamp:-
"Trinity Pro Preamp Features
The Trinity Pro Preamp allows for perfect balancing of a microphone and a pickup/transducer. Channel 2 is a designated mic channel with phase switch and supplies 9-volts to a lavalier type microphone. Each individual channel features volume, gain, +/- 20 dB bass, midrange, and treble filters. The EQ is accessible inside the box with trimpots. A convenient belt clip is included with this compact preamp, which weighs a mere ten ounces with the battery installed."
http://kksound.com/products/trinitypropreamp.php
From this, it looks like as long as your third party preamp supplies 9 volts DC to the microphone, it should be the same as the k & k preamp.