User manual LAVRY AD122-96 MKIII REV 1.4

[. . . ] Model AD122-96 Mark III 96kHz Mastering Quality Analog to Digital Converter Operations Manual Lavry Engineering, Inc. Box 4602 Rolling Bay, WA 98061 (360)598-9757 http://www. lavryengineering. com/ email: techsupport@lavryengineering. com Revision 1. 4 May 20, 2009 AD122-96 MKIII Operations Manual This page left blank. intentionally. AD122-96 MKIII Operations Manual MKIII PREFACE The MKIII is our 4th generation gold series analog to digital converter. The first gold AD, model AD122 (developed under our old company name ­ dB Technologies) was the first converter to reach 122dB dynamic range which is 20 bits of true performance. [. . . ] If you encounter problems getting the AD122-96MkIII to lock properly, or there are other devices in the "chain;" termination may be necessary. If the AD122-96MkIII is the only unit being fed the Word Clock signal, connect the cable using a BNC "T" adapter plugged into the "Word Clock Input. " On the other side of the "T", place a 75 Ohm BNC terminator connector. If the Word Clock is chained to other devices using "T" connectors, be sure that there is a 75 Ohm terminator on the "T" of the LAST device in the chain and that none of the other devices have INTERNAL TERMINATION. Alternately, if there is only ONE device with internal termination, it can be wired at the "end of the chain" in place of the terminator. The important point is that there is only ONE termination and it is located at the end of the chain. The same approach may be used to chain the Word Clock output of the AD122-96MkIII. In this case, there is no "T" on the AD122-96MkIII Word Clock Output. As described above, the "T" adapters should be placed on the Word Clock input of the devices the AD122-96MkIII is feeding, with the termination ONLY at the very end of the chain. Maintenance The Model AD122-96 MKIII is an auto calibrating converter requiring no periodic adjustments. The unit's reliance on linear power supplies and discrete class A analog circuitry generates significant amount of heat (25 watts maximum). The temperature rise is no cause for concern, but allowing for some airflow is always a benefit from a long-term reliability standpoint. The front panel is gold plated (24 karat gold). Use a soft cloth (and plain water, if necessary) to clean fingerprints. 10 AD122-96 MKIII Operations Manual Part II: Specifications Analog Inputs: The analog signal can be amplified by 0-12dB utilizing the front panel screw adjust trim pots. Fullscale signal with 0dB gain is 24dBu, (full-scale signal with 12dB gain is 12dBu). Input impedance over 0-100 kHz: greater than 20k ohm (pin 2 to pin 3). Noise Floor at 44. 1-48KHz sampling: -130dB ±1dB from full scale A weighted -126dB ±0. 5dB from full scale unweighted Noise Floor at 96KHz sampling: -127dB ±1dB from full scale A weighted -123dB ±1dB from full scale unweighted. Measuring noise floor with unconnected (opened) inputs may yield erroneous results. Unconnected high impedance inputs may pick up unwanted signals. Care must be exercised when measuring the noise floor. The signal applied to the converter must be lower then the noise floor. Ordinary relays and switches may leak too much signal, and it may be necessary to move a test tone signal to frequency above Nyquist (approx. Output Bits: 16 to 24 bits, user selectable. Total Harmonic Distortion and Noise: (Specified for 22-24 Bits output, balanced inputs) 0. 00005% for signals lower than -40dBF 0. 0004% for signals lower than -20dBF 0. 0008% for signals lower than -6dBF 0. 0012% for full scale signals Channel Separation: Greater than 120dB (0-20KHz) Sync. [. . . ] White noise is bounded between two limits. The probability of occurrence for any amplitude value between the two limits (boundaries) is equal; thus, it is also named uniform distribution noise. It is mostly "Gaussian", with higher probability of occurrence for smaller amplitudes. The large amplitudes occur less frequently and the distribution follows the familiar "bell shaped curve". [. . . ]