User manual RME ADI8DS

[. . . ] User's Guide SyncAlign ® ® TM SyncCheck Intelligent Clock Control Hi-Precision 24 Bit / 96 kHz 8 Channel AD / DA-Converter ADAT® optical / TDIF®-1 Interface Digital 24 Bit Interface / Format Converter TDIF-1 24 Bit Interface 2 User's Guide ADI-8 DS © RME Contents 1 2 3 4 Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 4. 1 Analog Specs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 4. 2 Digital Specs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 6 Inputs and Outputs 6. 1 Analog Inputs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [. . . ] A/D The clock source of the AD-converter can be Internal (quartz crystal), External (BNC word clock) and Input (the digital input signal TDIF or ADAT). The key DIGITAL INPUT determines the digital input being used, and the clock source in case INPUT was activated before. As not all combinations of clock settings make sense some of them are blocked. The limitations mainly affect TDIF operation and the setting Clock INTERNAL DA. In case an allowed combination can't be set simply press the D/A key, set A/D as desired, and set D/A back to its last state. The Lock state of the ADI-8 DS is indicated by a blinking (error) or constantly lit (Ok) EXT. or INPUT LED in the Clock section. Clock mode D/A Internal Clocking the DA-converter from the internal quartz crystal is propably the most outstanding feature of the ADI-8 DS. This technique provides simply the best sound quality, as the internal clock has very low jitter, so that the DA-converters can achieve the highest signal to noise ratio and lowest distortion. The setting Clock D/A INTERNAL requires a synchronous operation of all devices. To guarantee this the external device connected to the ADI-8 DS has to synchronize itself to the clock from the word clock output or ADAT/TDIF output of the ADI-8 DS. To prevent a not better but worse sound quality caused by imperfect or even no synchronisation, a special method called SyncCheck compares the synchronisity of the incoming data with the internal clock of the ADI-8 DS. The actual state is indicated by a blinking (error) or constantly lit (Ok) ADAT or TDIF LED in the DIGITAL INPUT section. In clock mode D/A INTERNAL the clock choices EXTERNAL and INPUT of the AD-section do not make sense, as the clock at the digital output has to be synchronous to the internal clock. Therefore A/D INTERNAL is automatically activated and cannot be changed. 12 User's Guide ADI-8 DS © RME 8. Word Clock 8. 1 Operation and Technical Background In the analogue domain one can connect any device to another device, a synchronization is not necessary. Correct interpretation of digital audio data is dependent upon a definite sample frequency. Signals can only be correctly processed or transferred between devices if these all share the same clock. Otherwise digital signals are misinterpreted, causing distortion, clicks/crackle and even dropouts. AES/EBU, SPDIF and ADAT optical are self-clocking (seen from a non-technical view TDIF too, as word clock is embedded inside the TDIF cable), so an additional line for word clock could be considered redundant. In practice however, using several devices at the same time can cause problems. For example, if devices are connected in a loop without there being a defined `master' device, self-clocking may break down. Besides, the clocks of all devices must be synchronized from a single source. [. . . ] Controls and Connectors Front AD-Converter Clock Section Select Input Level +4 dBu, -10 dBV Lo Gain Level Indication OK = -40 dBFS OVR= Overload Dither Double Speed Bit Split Clock Section AD and DA INPUT= Digital input signal EXT. = Word clock signal INT. = Crystal 44. 1 or 48 kHz DA-Converter Digital Input TDIF or ADAT AUX Sync Double Speed Bit Split Copy Mode Signal OK -40 dBFS Select Output Level Hi Gain, +4 dBu, -10 dBV On/Off Power Rear Word Clock Out Digital Outputs ADAT TDIF Digital Inputs TDIF ADAT Word Clock In Power Line Outputs ¼ " TRS Line Outputs D-sub Line Inputs D-sub Line Inputs ¼ " TRS User's Guide ADI-8 DS © RME 19 11. Connector Pinouts D-Sub analog input / output The 25 pin D-sub connectors of analog input and output are wired as shown in this table: Channel D-sub 1+ 24 112 2+ 10 223 3+ 21 39 4+ 7 420 5+ 18 56 6+ 4 617 7+ 15 73 8+ 1 814 GND is connected to pins 2, 5, 8, 11, 16, 19, 22, 25. Pin 13 is unconnected. D-Sub TDIF-1 The 25 pin D-sub connectors are wired according to TDIF-1, version 1. 1: Signal D-sub Out 1/2 1 Out 3/4 2 Out 5/6 3 Out 7/8 4 Out Out LRCK EMPH 5 18 Out FS0 6 Out FS1 19 Signal D-sub In FS1 20 In FS0 8 In In EMPH LRCK 21 9 In 7/8 10 In 5/6 11 In 3/4 12 In 1/2 13 GND is connected to pins 7, 14, 15, 16, 17, 22, 23, 24, 25. TRS-jacks of analog input / output The stereo ¼" TRS jacks of the analog inputs and outputs are wired according to international standards: Tip = + (hot) Ring = ­ (cold) The servo balanced input and output circuitry allows to use monaural TS jacks (unbalanced) with no loss in level. This is the same as when using a TRS-jack with ring connected to ground. 20 User's Guide ADI-8 DS © RME 12. [. . . ]