User's Guide OctaMic / OctaMic D Portable Professional Mic Preamp 8-channel Microphone / Line Preamp with Line Outputs Universal Power Supply Input Optional 8-Channel 192 kHz 24 Bit ADC AES-3 24 Bit Interface Contents Introduction............................................................ 3 Package Contents .................................................. 3 Brief Description and Characteristics................... 3 Technical Specifications ....................................... 3 4.1 Analog................................................................... 3 4.2 ADC Modul............................................................ 4 5 Power Supply ......................................................... 4 6 Operation and Usage 6.1 Controls................................................................. 5 6.2 Mic/Line Inputs ...................................................... 6 6.3 Line Outputs.......................................................... 6 7 The ADC Module 7.1 DIP Switches ......................................................... 7 7.2 External Synchronization....................................... 8 8 Digital Outputs 8.1 AES ­ Sub-D......................................................... 9 8.2 ADAT Optical .......................................................10 9 Word Clock 9.1 Operation and Technical Background ...................11 9.2 Cabling and Termination ......................................12 10 Technical Background 10.1 DS - Double Speed.............................................13 10.2 QS ­ Quad Speed ..............................................13 10.3 AES/EBU ­ SPDIF .............................................14 11 Accessories ...........................................................15 12 Warranty ................................................................15 13 Appendix ...............................................................15 14 Block Diagram OctaMic ........................................16 15 CE / FCC Compliance............................................17 1 2 3 4 User's Guide OctaMic © RME 2 1. Introduction Thank you for choosing the OctaMic. This unique Mic Preamp allows to connect any kind of microphone to any line level inputs. Thanks to the option of battery-powered operation and removable rack ears, the OctaMic makes an ideal companion to the Hammerfall DSP System in mobile recording situations. But excellent signal/noise ratio, sophisticated discrete Class-A technology, and lots of professional features make the OctaMic your first choice also in studio use! 2. Package Contents Please check that your OctaMic's package contains each of the following: · OctaMic · User's guide · Power supply 12 V / 1.25 A and power cord 3. Brief Description and Characteristics · · · · · · · · · · 8 separate microphone inputs with discrete Class-A frontend Phantom power 48V, low cut and phase switchable per channel 48V, Clip and Level LED per channel Gain +10 dB up to +60 dB adjustable per channel Reference level switchable Hi Gain / +4 dBu / -10 dBV Fully compatible to RME's ADI-8 series and HDSP series Servo balanced inputs and outputs Wide frequency response with special RF input filters Wide operating voltage range 100% hum-free via internal switching regulators 4. Technical Specifications · · · · Current drawn at 12 Volt operating voltage: 850 mA (10 Watts) Accepted power supply voltage DC 8 V ­ 28 V, AC 8 V ­ 20 V. Dimensions: 483 x 44 x 205 mm Weight: 2 kg 4.1 Analog · · · · · · · · · · Inputs: XLR or 1/4" TRS (stereo) jack, servo balanced Impedance: 2 kOhm Signal to Noise ratio (SNR): 129 dB EIN @150 Ohm THD: 0.006% @ 30 dB Gain Crosstalk: > 110 dB Frequency response ­0.5 dB: 5 Hz - 200 kHz Line Out: 1/4" TRS (stereo) jack, servo balanced Maximum output level: +21 dBu Output impedance: 47 Ohm Output level switchable Hi Gain / +4 dBu / -10 dBV · SNR ADC Module: > 110 dBA · Sample rate range ADC Module: 28 kHz ­ 200 kHz · THD ADC Module: < 0.00032 %, < -110 dB User's Guide OctaMic © RME 3 4.2 ADC Modul AES Input · · · · · 1 x XLR via 25 pin D-sub, transformer balanced, ground-free, according to AES3-1992 High-sensitivity input stage (< 0.3 Vss) SPDIF compatible (IEC 60958) Lock range: 27 kHz ­ 200 kHz Jitter when synced to input signal: < 2 ns Wordclock Input · · · · · · · · BNC, not terminated (10 kOhm), switch for internal termination 75 Ohm Automatic Double/Quad Speed detection and internal conversion AC-coupling, not effected by DC-offsets within the network Signal Adaptation Circuit: signal refresh through auto-center and hysteresis Overvoltage protection Level range: 1.0 Vss ­ 5.6 Vss Lock range: 27 kHz ­ 200 kHz Jitter when synced to input signal: < 2 ns AES/EBU Outputs · · · · · 4 x via 25 pin D-Sub, transformer balanced, ground-free, according to AES3-1992 Output voltage Professional 4.5 Vss, Consumer 2.1 Vss Format Professional according to AES3-1992 Amendment 4 Format Consumer (SPDIF) according to IEC 60958 Single Wire: 4 x 2 channels 24 bit, up to 96 kHz ADAT Optical · 2 x TOSLINK · Standard: 8 channels 24 bit, up to 48 kHz · Sample Split (S/MUX): 2 x 8 channels 24 bit / 48 kHz, equalling 8 channels 24 bit 96 kHz 5. Power Supply In order to make operating the OctaMic as flexible as possible, the unit contains a switching regulator of the latest technology, which not only has a high efficiency (> 90%), but also prevents internal hum noise by operating at 150 kHz. Another advantage: the OctaMic accepts any power supply with voltages between 8 and 28 V DC, no matter which polarity, and even between 8 and 20 V AC. Given the power supply can deliver the current needed. The supplied high-quality switching power supply, 12 V / 1.25 A, not only accepts any mains voltage between 100 V and 240 V (usable world-wide), but is also fully regulated against voltage fluctuations. Additionally it only weighs 150 g in spite of its high power of 15 Watts. The large voltage range of the OctaMic also allows for the use of a rechargeable lead-battery instead of a power supply, for completely independent mobile operation. A matching connection cable (power jack to terminals 6.3 mm) is available from RME. A Panasonic LCR122R2PG battery, 12 V 2.2 Ah, can operate the OctaMic for 2 hours. User's Guide OctaMic © RME 4 6. Operation and Usage 6.1 Controls The front of the OctaMic has the gain knobs, switches for low cut, phantom power and phase, Clip Hold, Reference Level and several status LEDs: +48V (LED) lights up when phantom power is active. Phantom power should only be activated when using condensor microphones which require such a power supply. The CLIP LED has been designed to act like the OVR LEDs of the ADI-8 series. It lights up 2 dB before the chosen reference level plus a headroom of 9 dB. At Hi Gain the LED lights up at +17 dBu output level, selecting +4 dBu it lights up at +11 dBu. SIG (Signal) indicates the presence of an input signal. The LED has a detection range of more than 50 dB using multiple brightness states. With this, SIG acts as useful level control, helping to set GAIN correctly. GAIN allows for a stepless and very precise adjustment of the amplification between +10 dB and +60 dB. +48V (switch) activates phantom power. Phantom power should only be activated when using condensor microphones which require such a power supply, and only on the specific channel. LO CUT activates a hi-pass at 80 Hz, 18 dB per octave. This filter can remove rumble and other low frequency noise. PHASE changes the polarity. Phase cancellations and sound changes can be caused by using multiple microphones at different places, or wrongly soldered cables. In such cases PHASE can eliminate the error by adding an additional phase inversion. Clip Hold is activated by pressing the key for two seconds. As soon as an overload is detected, the corresponding Clip LED begins to flash once per second. With this, a momentary overload stays visible for a longer time. Pressing the key once resets the Clip display. Pressing the key again for two seconds deactivates the Clip Hold mode. Hi Gain / +4 dBu / -10 dBV: Defines the reference level of the Line Level Outputs. See chapter 6.3, Line Outputs. The back of the OctaMic has the 8 analog inputs and outputs, the power supply connector AUX, the analog D-sub output, or the optional ADC module (see chapter 7) with all the digital inputs and outputs. MICROPHONE / LINE INPUTS: 8 Neutrik XLR / TRS combo jacks. Thanks to the servo balanced designs and a high maximum input level (+10 dBu), the inputs can be used balanced or unbalanced, with XLR or TRS jack, with microphone or line levels ­ nearly everything is possible. LINE LEVEL OUTPUTS: 8 TRS (stereo) jacks. The electronic output stage is built in a servo balanced design, handling monaural (unbalanced) and stereo jacks (balanced) correctly. AUX: Connect power supply, lead-battery or battery. See chapter 5, Power Supply. User's Guide OctaMic © RME 5 6.2 Mic/Line Inputs The OctaMic offers 8 balanced Mic and Line inputs via 1/4" TRS (stereo) and XLR combo jacks. The electronic input stage is built in a servo balanced design which handles monaural and stereo jacks correctly. When used unbalanced it automatically corrects the gain by 6 dB. When using unbalanced cables with stereo TRS jacks, the 'ring' contact of the cable's jack should be connected to pin 1 (ground). Otherwise noise may occur, caused by the unconnected negative input of the balanced input. The pinout follows international standards. XLR pin 2 + or hot, pin 3 ­ or cold, pin 1 ground. TRS tip + or hot, ring ­ or cold. 6.3 Line Outputs The 8 short circuit protected, low impedance and servo balanced line outputs are available as (stereo) 1/4" TRS jacks. The electronic output stage is built in a servo balanced design which handles monaural and stereo jacks correctly. When used unbalanced it automatically corrects the gain by 6 dB. The pinout follows international standards. TRS tip + or hot, ring ­ or cold. To maintain an optimum level for devices connected to the analog outputs, the OctaMic includes a switch which allows to change the reference level of all 8 outputs simultaneously. The OctaMic can generate a maximum level of +21 dBu without distortion. However, the CLIP LED has been designed to act like the OVR LEDs of the ADI-8 series. It lights up 2 dB before the reference level selected on the back of the unit, plus a headroom of 9 dB, is reached. At Hi Gain the LED lights up at +17 dBu output level, selecting +4 dBu it lights up at +11 dBu, selecting ­10 dBV it lights up at 0 dBV. Setting Hi Gain +4 dBu -10 dBV Reference +19 dBu +13 dBu +2 dBV Clip LED +17 dBu +11 dBu 0 dBV True Clip +21 dBu +15 dBu +4 dBV ADC Level -2 dBFS -2 dBFS -2 dBFS This also means that the CLIP LED lights up 4 dB before the OctaMic actually reaches the maximum level. Such an additional headroom is considered to be useful in real world operation. The chosen reference level has no meaning for the ADC module. The ADC modul is designed for a level of ­2 dBFS as soon as the Clip LED lights up. Selecting +4 dBu the output signal is attenuated by 6 dB, so for the same output level the amplification has to be increased via GAIN. With this trick the OctaMic reaches the maximum signal to noise ratio on +4 dBu based inputs (like our ADI-8 series), because microphone preamps have better EIN values at higher amplification. In case of an extreme recording situation, where the gain of the OctaMic is no longer sufficient, selecting Hi Gain will again provide the highest amplification possible. The same is true and even more efficient at ­10 dBV. In this case the output level is reduced by around 14 dB ­ the same happens to the basic noise of the unit! User's Guide OctaMic © RME 6 7. The ADC Module The ADC Module replaces the analog D-sub output by a high quality digital converter card. The card includes clock generation, clock recovery (SteadyClock) and AD-conversion. 7.1 DIP Switches The DIP switches are used to configure the ADC Module. The following diagram, also printed on the back of the unit, shows the function controlled by each switch. DIP Switch 1 2 3 4 5 6 Function External synchronization source AES (D-sub) or word clock (BNC) Clock internal (Master) or external (Slave) Internal Clock 44.1 kHz or 48 kHz Activates Double Speed Mode* Activates Quad Speed Mode* AES output signal Professional or Consumer *Note on DIP switch 4/5: At internal clock, the switches DS and QS multiply the value set with switch 3 by a factor of 2 or 4. So if switch 3 is set to 48 kHz, switch 4 will turn it into 96 kHz, switch 5 turns it into 192 kHz. At external clock switch 3 is of no meaning, because the unit is synchronized to the incoming clock. However, switch 4 and 5 define the frequency range between Single Speed, Double Speed and Quad Speed. For example if the OctaMic shall operate at 176.4 or 192 kHz, switch 5 has t ...