Hi Tom,
The Micro Line Drive (MLD) has both a passive and active signal path. Unlike the TLC-1 (with buffered unity-gain path) the MLD's active circuit is a more traditional gain stage (adjustable via internal jumpers to +6 or +12dB). If you are looking for more dynamic punch or slam, that should do the trick.
Feel free to contact SMc Audio if you have any further questions.
Best regards,
Steve McCormack