The API A2D represents a landmark achievement for API; it is the first product ever produced by the company with an integrated digital output. Recognizing the desire for a high quality solution to raise microphone signals to a workable line level, we engineered one of our most popular mic preamp designs into an enclosure with our new proprietary analog to digital conversion. The result is a complete package – a pair of superb mic preamps feeding an A/D section with a set of standard digital interface outputs, multiple sample-rate choices, and internal or external clock options. Precise control of both the analog gain as well as the level feeding the digital section means that the mic signal can be maintained super-clean if desired, or driven harder on the analog side for that whallop and impact that can only be achieved by driving the transformer into saturation for that historic API sound!
The A2D analog section consists of the circuitry contained in two API 312 mic preamps, or one half of the popular 3124 quad mic preamp rack product. A level control pot with an expanded 20-segment metering system shows precise mic gain levels. Control switches include polarity, 48v phantom power, input pad, 2:1 transformer routing, and Mic/Line select. Each analog input contains a balanced low-level XLR connector and a high-level line input on a 1/4 inch jack.
The Digital section of the A2D includes two 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 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. This allows the A2D to have external analog processing devices inserted in the audio chain (EQ, compression, etc.)
Digital interface connectors provided are SPDIF single ended RCA connector and AES digital out on XLR. A coaxial BNC accepts external “Super Clock” which will illuminate the front panel EXT SYNC LED when locked.
In addition, there are a pair of 9-pin D-sub connectors which allow the linking of multiple A2D units, all operating off the first sample-rate clock in the chain.