The API A2D features of a pair of API 312 Mic Preamplifiers that feed an A/D section with a set of standard digital interface outputs, multiple sample-rate choices and internal or external clock options. Analogue gain knobs are offered so that the level feeding the converters can be kept clean or driven harder for a punchier and warmer sound.

The A2D analogue section consists of the circuitry contained in two 312s, half of that of the popular API 3124+. A level control pot with an expanded 20-segment metering system shows precise mic gain levels, while control switches include polarity, 48v phantom power, input pad, Mic/Line select and 2:1 transformer routing, which selects a lower gain contribution from output transformer. Each analogue input contains a balanced low-Z input XLR connector and a high-Z instrument input on a ¼-inch jack.

The digital section of the A2D includes two API discrete 2510 amplifiers with level pots to adjust the feed to the A/D converters, each with a corresponding 20-segment calibrated meter. A multi-position switch selects the desired sample frequency. The External Sync LED will light when an external clock signal is used.
Rear panel analogue connectors include an XLR input and output for each channel, as well as a balanced ¼-inch TRS insert to the A/D converter. The TRS insert allows the A2D to have external analogue processing devices inserted in the audio chain (EQs, compressors, etc.).

The A2D’s digital interface connectors are a SPDIF single-ended RCA connector and an AES digital out on XLR. A coaxial BNC accepts external Super Clock, which will illuminate the front panel EXT SYNC LED when locked.
Additionally, the A2D comes with a pair of 9-pin D-sub connectors that allow the multiple units to be linked together with all units operating off the first sample-rate clock in the chain.

• A pair of signature API 312 Mic Preamplifiers
• API 2510 and 2520 Operational Amplifiers
• 20 Segment LED metering on both analog and digital sections
• Mic and Instrument inputs
• Polarity, phantom power, input pad, 2:1 transformer routing, Mic/Line switches
• Six sample rate choices
• Sync to external Word Clock with feed through BNC
• External Super Clock input
• Ability to be slaved with other A2D units
• Insert point provided between analog and digital sections