Avalon AD2022 Dual Mono Pure Class "A" Discrete Microphone Preamplifier with DIThe AD2022 is Avalon's fourth generation of fully discrete, symmetrical Pure Class A microphone preamplifiers. The dual mono AD2022 includes the original sonic capabilities and transparency of the M2, M22 and M5 preamplifiers plus several additional features, including selectable microphone source loading for optimized cable mic matching, improved high voltage Class A regulated power supplies, two high Z instrument inputs, variable passive high pass