In the words of Hudson Electronics:

The Broadcast AP-II is a dual preamplifier pedal designed in conjunction with guitarist, Ariel Posen. It features two independent, differently-voiced preamplifier circuits which each add their own subtle color. The first is fitted with a silicon transistor and transformer, bringing the smooth, darker tone of the original Broadcast-AP. The second removes the transformer and replaces the silicon with a germanium transistor, resulting in a brighter, more aggressive tone. Each circuit has a large gain range, and cascading one into the other provides further sonic options, from subtle boosts through to heavily-distorted sounds.