The HR-ADC1 is a broadcast quality A/D converter that provides exceptional audio accuracy and clarity with any audio source or style. Superior analog performance fine tuned through audiophile listening practices produces very low distortion (0.0006%), exceedingly low noise (-135 dB) and remarkably flat frequency response (+/- 0.05 dB). This performance is coupled with unparalleled metering flexibility and programmability with average mastering level monitoring and peak value storage. With external sync capability plus front-panel settings up to 24 bits and up to 192 kHz sample rate, the HR-ADC1 is the single instrument needed for A/D conversion in demanding applications. The HR-ADC1 accepts balanced +4 dBu or unbalanced -10 dBV stereo audio through rear panel XLR or RCA jacks or through a detachable terminal block. An external AES/EBU, AES-3ID or S/PDIF sync source may be connected through a rear-panel XLR, RCA or BNC jack. Digital audio outputs are provided in AES/EBU, AES-3ID or S/PDIF formats. The rear-panel switch-selected output format is available on the corresponding XLR, RCA or BNC jack. Front panel LEFT and RIGHT controls permit input gain adjustment to produce the desired average signal level for the digital conversion. The zero decibel (0 dB) reference level of the audio metering string may be set to -14, -16, -18 or -20 dBFS. The meter may also be set to display peak or VU average audio levels. Audio peaks between -10 dBFS and 0 dBFS (clipping) are displayed separately to the right of the standard audio level meter. The peak display may be set to either flash or store the peak values. Flash duration settings provide for instantaneous, 1/3 second hold or 2/3 second hold. If the peak display is set to STORE then the highest peak recorded remains displayed until the PEAK RESET button is pushed. The HR-ADC1 provides rear-panel inputs for an external sync source. If valid external sync is connected, the EXTERNAL SYNC LOCK LED illuminates. The front-panel SYNC button sets the converter to synchronize to the external source. When external sync is not used, the HR-ADC1 converts at the sample rate selected using the front-panel RATE button. The number of BITS is user-selectable on the front panel. The peak LEDs double as the programming indicators during setup. The MODE MENU has four selection categories: METERING RSP (peak or average response) for the main audio meter; METERING 0 REF (sets meter scaling to -14, -16, 18 or -20 dBFS for a 0 dB reading); DISPLAY BRT (sets LED display brightness for ambient light); DISPLAY PEAK (sets peak LED string to FLASH, hold 1/3 second, hold 2/3 second, or STORE the maximum peak reading. Programming selections are automatically stored after five seconds and are retained in memory when the HR-ADC1 is re-powered. The HR-ADC1 is powered from 24 Vdc, which may be connected through the detachable terminal block or through the dc power jack. A front-panel power switch is provided.