The AD2022 Microphone Preamp 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. These include selectable microphone source loading for optimized cable/microphone matching, improved high-voltage Class A regulated power supplies, two high Z instrument inputs, variable-passive high pass filter, teflon/silver wiring and doubled plated circuit boards for superior low level signal transfer.
The AD2022 features split low-ratio primary windings which are carefully combined within a custom mu-metal core for extended smooth frequency response and very low distortion. The input signal selector, high pass filter, polarity-phase reverse, +48v power and the 20dB input attenuator all utilize local sealed relay operation. A variable, passive high pass filter provides a minimum phase shift design while eliminating low frequency rumble, wind noise and mechanical vibration at sub sonic frequencies.
Two 100% discrete, high-voltage, symmetrical Pure Class A signal amplifiers are utilized per channel of the AD2022. The first operates in a cascaded-cascode FET configuration while the second stage amplifier is fully bipolar. The twin amplifiers share the total available gain requirement. This shared architecture increases the high level headroom capability, improves transient response and doubles the internal bandwidth of the ultra-high performance pure Class A signal amplifiers. High-current DC coupled, Class A discrete amplifiers are utilized for the output drive interface with +36dB capability into all known loads. Two large, high-quality analog VU meters indicate accurate signal readings while bi-color LED's offers peak indication at 0dB and +20dB.