• AD2022 PREAMPLIFIER SPECIFICATIONS

• Circuit Topology: Twin cascode FET and bipolar low level signal amplifiers,

• high-voltage, 100% discrete, symmetrical Pure Class A

• Input Type and Load: Transformer balanced low-ratio, 50, 150, 600 and 1k5 ohm input load selection

The AD2022 is Avalons 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 filter, teflon/silver wiring and doubled plated circuit boards for superior low level signal transfer.MICROPHONE INPUTThe AD2022 incorporates the most advanced high-performance microphone transformer available. Split low-ratio primary windings are carefully combined within a custom mu-metal core for extended smooth frequency response and very low distortion. Sealer silver relays are used for minimal signal invasion. 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. SYMMETRICAL PURE CLASS A DESIGNTwo 100% discrete, high-voltage, symmetrical Pure Class A signal amplifiers are utilized per channel. The first operates in a cascaded-cascode FET configuration while the second stage amplifier is fully bipolar.