Rear panel analog connectors include an XLR input and output for each channel, as well as a balanced 1/4" TRS insert to the A/D converter. The External Sync LED will light when an external clock signal is used. A multi-position switch selects the desired sample frequency. The digital section of the A 2D 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. Each analog input contains a balanced low-Z input XLR connector and a high-Z instrument input on a 1/4" jack.
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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. The A 2D Analog section consists of the circuitry contained in two 312s, half of that of the popular API 3124+. Precise control of both the Analog gain and the level feeding the digital section means that the microphone signal may be kept super-clean if desired or driven harder to achieve the warm, punchy "API sound." The first API product with an integrated digital output, the A 2D contains 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.
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