The Tremolo circuit was slightly modified for a deeper and richer tremolo sound The Reverb circuit has also been modified to deliver a smoother, less intense reverb sound.
The Columbia comes standard with a 6V6 tube configuration. The amp can accommodate a 6L6 configuration for 28 Watts of output power. An additional feature with the 6L6 configuration is a 4k/8k option. This allows the player to simply switch the load to provide a cleaner or more distorted sound. The 4k option provides cleaner tones, while the 8k will lower the wattage and provide quicker mid-range break up.
The original Pinceton Reverb had volume, treble and bass controls. The Louis Electric Columbia Reverb has added a middle control knob for additional tone shaping.