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projects:hifi:retrofitting_coaxial_spdif_out [2023/04/08 01:39] – admin | projects:hifi:retrofitting_coaxial_spdif_out [2024/10/24 12:41] (current) – admin | ||
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====== Retrofitting coaxial spdif out ====== | ====== Retrofitting coaxial spdif out ====== | ||
- | This page describes how to add to a device | + | This page describes how to add to a device |
The modification described on this page is to add a coaxial spdif output to a Sony MDS-JE520 MiniDisc deck. Although it contains both an optical and coaxial spdif input, it only contains an optical spdif output. The lack of a coaxial spdif output is inconvenient and this modification mitigates that. | The modification described on this page is to add a coaxial spdif output to a Sony MDS-JE520 MiniDisc deck. Although it contains both an optical and coaxial spdif input, it only contains an optical spdif output. The lack of a coaxial spdif output is inconvenient and this modification mitigates that. | ||
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| //Schematic of spdif coax interface// | | //Schematic of spdif coax interface// | ||
- | The schematic is in essence an impedance matched voltage divider. Since the transformer has a 1:1 ratio, the signal is AC only and the three inverter driver outputs U1A, U1B and U1C are all identical, the schematic can be simplified for calculation. | + | The schematic is in essence an impedance matched voltage divider. Since the transformer |
S/PDIF signals are defined in IEC 60958-3 (2003)((Digital audio interface, Part 3)). The output shall have a substantial resistive impedance of $(75\ \pm\ 15) (\Omega)$ when measured at frequencies from 0.1 MHz to 128 times the maximum frame rate, which equals to about 5.6 MHz for a sample rate of 44.1 kHz. The signal amplitude shall be $(0.5\ \pm\ 0.1 ) {\text V}$ peak-to-peak, | S/PDIF signals are defined in IEC 60958-3 (2003)((Digital audio interface, Part 3)). The output shall have a substantial resistive impedance of $(75\ \pm\ 15) (\Omega)$ when measured at frequencies from 0.1 MHz to 128 times the maximum frame rate, which equals to about 5.6 MHz for a sample rate of 44.1 kHz. The signal amplitude shall be $(0.5\ \pm\ 0.1 ) {\text V}$ peak-to-peak, |