User Guide Mode d'emploi
Contents
1. 212. 1 192kHz C ow w Lee eme nese AS 2 ew sw ew ew sw EESTI E SS REIS CN nee use eau fasse ner EE exo ono wc ne ves sw ness St LBE 3m 17929 3x7 3 Fs ono end nD s esse aesa sos sors ass SPor se 24 bit 192kHz ADAT interface operation Jumpers disabled default ProTools ProTools Compatible The card provides digital outputs for all eight ISA 828 channels which operate over the sample frequency ranges 44 1 192kHz The card features two ADAT type lightpipe output connectors For speeds up to 48kHz both connectors transmit all 8 channels simultaneously However ADAT type connectors are bandwidth limited at sample rates 88 2kHz and 96kHz each audio channel uses two ADAT digital channels to accommodate the increased quantity of data SMUXII At sample rates 176 4kHz and 192kHz each audio channel uses four ADAT digital channels to accommodate the increased quantity of data SMUXIV The ADAT output connectors operate as follows 44 1 48kHz sample rates Connector 1 channels 1 to 8 in parallel Connector 2 channels 1 to 8 in parallel identical to connector 1 88 2 96kHz sample rates Connector 1 channels 1 to 4 Connector 2 channels 5 to 8 176 4 192kHz sample rates Connector 1 channels 1 and 2 Connector 2 channels 3 and 4 ADAT lightpipe cables are available from you
3. active on the instrument input In this case pressing the Z In switch toggles between High and Low impedance settings The impedance values are as follows Low 470 kO High 2 4 MO Metering The vertical columns of LEDs indicate the peak signal levels of channels 1 8 in one of two modes defined by the state of the Meters Pre ADC switch on the front panel Mode 1 Meters Pre ADC switch disengaged This is the default state and the mode to use when no digital output card is installed Meters 1 to 8 indicate the analogue level directly after the Gain stages set on the front panel OdBFS reached when the red LED is lit indicates that a signal level of 22dBu is present at the analogue output 18dBFS unless recalibrated on the rear panel see description on page 8 therefore indicates that there is a signal level of 4dBu at the analogue output Mode 2 Meters Pre ADC switch engaged This is the mode to use when the analogue input signals are being routed to other hardware devices such as dynamics processors using the analogue outputs ADC Input on the rear panel acting as sends returns before converting to digital Obviously the optional digital output card should be installed if wanting to use this mode Meters 1 to 8 indicate the peak level of channels 1 8 received at the ADC Input OdBFS reached when the red LED is lit indicates that a signal level of 22dBu is present at the ADC Input connector 18dBFS unless recalibrated on the
4. external word clock source connected to the word clock input on the rear panel Selecting 256x allows the ISA 828 to be slaved to an external clock running at 256 times faster than the sample frequency and enables connection to systems such as the Digidesign Superclock or other 256x slave clock devices Both options have LEDs to indicate selection with neither LED illuminated the 828 will synchronise to its own internal clock Lock LED When lit LOCK indicates that the unit is successfully synchronised to an external clock Note When using 256x external clock no lock indication is given if audio can be heard in this mode then 256x clock is locked Applications Mic Pre amp Input Impedance A major element of the sound of a mic pre is related to the interaction between the specific microphone being used and the type of mic pre amp interface technology it is connected to The main area in which this interaction has an effect is the level and frequency response of the microphone as follows Level Professional microphones tend to have low output impedances and so more level can be achieved by selecting the higher impedance positions of the ISA 828 mic pre amp Frequency response Microphones with defined presence peaks and tailored frequency responses can be further enhanced by choosing lower impedance settings Choosing higher input impedance values will tend to emphasise the high frequency response of the microphone connected all
5. level inputs There are also 2 25 pin D type connectors one for the analogue outputs and another for sending an external signal to the optional ADC most likely if using the Insert switches on the front panel and returning the mic line inst signals from additional processing for digital conversion Lastly there are digital connections if the optional ADC is fitted and a voltage switching power socket to connect to the internal power supply Q Should balanced connectors be used with the ISA 828 A Yes where possible Alternatively if using an unbalanced instrument source you can connect to the four unbalanced 1 4 inputs on the front panel Q Is there an optional digital input card A No because the ISA 828 is primarily a front end product In other words the only devices that are likely to be connected to the 828 s inputs are analogue sound sources such as microphones guitars etc Q Why is the 24 bit 192kHz specification important A An A D converter works by sampling the audio waveform at regular points in time and then quantizing those values into a binary number which relates to the number of bits specified The quantized signal must then be passed through a D A converter before it becomes audible In simple terms the D A essentially joins the dots plotted by the A D converter when the signal was first converted to digital The number of dots to join combined with how little those dots have been moved determines how acc
6. mode switch With the switch in channels 1 8 are available as S PDIF and AES formats number of channels available in AES format is dependent on wire mode switch See the table on page 11 for pinout details 1 Wire 2 Wire AES mode switch For sample rates from 88 2 to 192kHz a dual wire mode is available for connecting to older equipment with AES inputs which can only receive speeds up to 192kHz by using both digital channels of a single AES connection known as 2 wire Engaging this switch splits the digital signal and activates dual wire mode which means that half the number of channels are transmitted down the same number of wires Transmitting channels 1 8 in 2 wire mode requires all of the pins of the DB25 connector Therefore if the S PDIF mode is selected only channels 1 4 can be transmitted as AES format See the table on page 11 for pinout details 10 In single wire mode switch out the AES channels 1 8 can be transmitted at sample rates up to 192kHz using only 8 AES connections Therefore channels 1 8 are always available in AES format regardless of the S PDIF switch setting ADC Card DB25 Pin Out Configurations Jumpers disabled Jumpers enabled Jumpers enabled S PDIF Jumpers enabled Single Jumpers enabled S PDIF Dual Wire Mode amp witch Dual Wire Wire Mode 44 1 192kHz Switch In Single Wire 88 2 192kHz i Dual Wire Mode Mode 88 2 192kHz Compatible 44 1 96kHz P 08 2 192kHz Mode 44
7. pin connector on the rear panel routes to the digital output card if connected rather than the direct mic line or instrument signal Note that the mic line or instrument signal will still route to the analogue output on the rear panel with this switch active This switch is designed to allow the input signal to be routed to other hardware for processing out of the analogue output and then back into the 828 using the ADC input for digital conversion The Meters Pre ADC switch on the front panel allows the return signal level to be viewed on the LED strip meters before conversion see the Metering section below for details HPF Pressing the HPF switch makes the High Pass Filter for that channel active in the audio path This is useful for removing any unwanted bass caused by proximity effect or rumble The filter provides a 75Hz knee frequency with 18dB octave roll off Input Impedance Pressing the Z In switch steps through each of the four transformer pre amp input impedance values as indicated by the corresponding LEDs By selecting different values for the impedance of the ISA 828 transformer input the performance of both the ISA 828 pre amp and the microphone connected can be tailored to set the desired level and frequency response The impedance values are as follows Low 600 Q ISA 110 1k4 O Med 2k4 O High 6k8 O A guide to setting input impedance is available in the Applications section The impedance switch is also
8. signal is very useful for two reasons When high gain is required Using trim in conjunction with the mic gain of 60dB gives a total of up to 80dB of pre amp gain making it very useful for getting good digital recording levels from very low output dynamic and ribbon microphones Gain adjustment during recording When small amounts of gain adjustment are needed to correct performance level variations during recording use the trim knob rather than the stepped mic line gain knob as switching the 10dB gain steps would be much too intrusive It is therefore good practice to apply some Trim gain before using the 10dB stepped gain knob to find the optimum recording level so that the Trim control can be used to gently add or take away gain later if so required 48V Pressing the 48V switch provides phantom power suitable for condenser microphones to the rear panel XLR microphone connector This switch does not affect the other inputs If you are unsure whether your microphone requires phantom power refer to its handbook as it is possible to damage some microphones most notably ribbon microphones by providing phantom power Phase Pressing PHASE inverts the phase of the selected input to correct phase problems when using multiple microphones or when incorrect wiring polarity has occurred Insert In Activating the INSERT switch illuminated when active breaks the signal path of the channel so that the signal connected to the ADC Input 25
9. IRE SPDIF TRIM IN WORD CLOCK OUT f DIGITAL OUTPUT i e J ANALC IUE AESISPDIF Focusrite Mains IEC connector Analogue Outputs Balanced Line Inputs Mic Inputs 1 8 XLR 1 8 25 pin D type 1 8 TRS Jack Analogue Inputs On the rear panel there are 8 XLR inputs for connecting microphones and 8 1 4 TRS inputs for line level sources Each one is numbered accordingly and corresponds to the relevant section on the front panel All 3 pin XLR balanced audio connectors are wired as follows Pin 1 Screen Chassis Pin 2 Audio 0 Pin 3 Audio 180 All 1 4 balanced jack connections are wired as follows Tip Audio 0 Ring Audio 180 Sleeve Screen Chassis Analogue Outputs Eight balanced analogue outputs are transmitted via a 25 pin connector that utilises the DB 25FM Tascam Pro Tools pinout as follows Pin out for TASCAM DB25 8 Channel Balanced Connector 1 LE BE LE SE GE CE SE GCHGCHGCHGCHGCHGCHGCHGCH 220 4O BO 20 nO 2O 9O vO 50 H HOT C COLD G GROUND ADC Input An additional 25 pin connector also following the Tascam Pro Tools standard allows 8 analogue channels to be sent to the digital card if installed for conversion This means that any or all of the 8 input signals mics lines instruments could have their Insert switches engaged and be sent to additional audio processors using the analogue outputs then be returne
10. ISA 828 User Guide Mode d emploi ED _ Focusrite ocusrite co WARNINGS amp CAUTIONS THE APPARATUS SHALL NOT BE EXPOSED TO DRIPPING OR SPLASHING AND NO OBJECTS FILLED WITH LIQUIDS SUCH AS VASES SHALL BE PLACED ON THE APPARATUS VENTILATION SHALL NOT BE IMPEDED BY COVERING THE VENTILATION OPENINGS WITH ITEMS SUCH AS NEWSPAPERS CLOTHS CURTAINS ETC NO NAKED FLAME SOURCES SUCH AS LIGHTED CANDLES SHOULD BE PLACED ON THE APPARATUS MAINS LEAD THIS EQUIPMENT MUST BE EARTHED AND FITTED WITH THE CORRECT LEAD FOR THE COUNTRY OF OPERATION THIS WILL NORMALLY BE ACHIEVED FROM THE CORRECT MAINS SUPPLY SOCKET DO NOT USE A DAMAGED OR FRAYED POWER CORD IF THE MAINS PLUG SUPPLYING THIS APPARATUS INCORPORATES A FUSE THEN IT SHOULD ONLY BE REPLACED WITH A FUSE OF IDENTICAL OR LOWER RUPTURE VALUE SHOULD THE APPARATUS OR SUPPLY CORD BECOME PHYSICALLY DAMAGED THEN IT SHOULD NOT BE POWERED AND ADVICE SOUGHT FROM SUITABLY QUALIFIED PERSONNEL THIS UNIT MUST BE EARTHED BY THE POWER CORD UNDER NO CIRCUMSTANCES SHOULD THE MAINS EARTH BE DISCONNECTED FROM THE MAINS LEAD This unit is capable of operating over a range of mains voltages as marked on the rear panel Ensure correct mains voltage setting and correct fuse before connecting mains supply Do not change mains voltage settings while mains supply is connected To avoid the risk of fire replace the mains fuse only with the correct value fuse as marked on the rear panel The internal power s
11. T Selects 1 wire or 2 wire mode for ADATTM Outputs 1 8 across both connecting a 176 4 or 192kHz AES 44 1 48kHz 1 4 then 5 8 a 88 2 96kHz signal to older equipment and 1 4 0 176 4 192kHz Digital Outputs AES S PDIF A 25 pin Tascam DB 25FM connector allows up to 8 channels of 24 bit digital audio AES or S PDIF to be transmitted to a DAW or other digital storage medium The card can be configured using jumpers on the card and using two push button switches on the rear panel The table on page 11 shows the pinout details for all available configurations Below is a brief description of the overall functionality available Jumper position The digital card has four jumpers movable plastic clips that can be positioned so as to disable AES outputs 5 8 and therefore make the 828 pin to pin compatible with a Pro Tools HD 192 interface using a standard 25 pin to 25 pin cable With the jumpers in the disabled position default channels 1 8 are available at 44 1 96kHz and channels 1 4 at 176 4 192kHz Depending on the position of 1 wire 2 wire switch See Appendix 1 for details of the cable pinout for recording all 8 channels to Pro Tools at 192kHz jumpers are enabled in this case AES S PDIF switch This switch selects whether the signal is professional AES or consumer S PDIF digital format With the switch out channels 1 8 are in AES format and are duplicated across the connector allowing 16 outputs dependent on wire
12. ative input response colours Also there are inserts per channel plus fixed 75Hz HPF phase reverse and phantom power Q What s significant about the impedance switching for each pre A Each pre can either be matched perfectly to any microphone vintage or modern or offset to offer a variety of response colours by interacting with any particular microphone The impedance of each preamp is switchable via a single switch labelled Z In between 4 settings original ISA 110 Zobal network influence for the classic Vintage Focusrite sound Low 600 Ohms High 2 4k and Higher 6 8K relatively lively great for room ambience For more information read the impedance guide in the Applications section Q Are insert points featured A Yes switchable in or out of circuit on each of channels 1 8 Q What do the insert switches actually do A Activating an insert switch for an input switches the signal fed to the ADC for that channel to the corresponding one received at the ADC Input on the rear panel This is so that the mic line inst signals can be sent to additional hardware such as compressors using the analogue outputs before being converted by the optional digital card Q What are the four extra inputs on the left hand side of the front fascia for A They are unbalanced inputs that enable you to easily connect unbalanced sources like guitars basses to the unit without the need for an external DI box Q What
13. ble To minimise microphone loading and to maximise signal to noise ratio pre amps have traditionally been designed to have an input impedance about ten times greater than the average microphone around 1 2kQ to 2kQ The original ISA 110 pre amp design followed this convention and has an input impedance of 1 4kQ at 1kHz Input impedance settings greater than 2kO tend to make the frequency related variations of microphone outputs less significant than at low impedance settings Therefore high input impedance settings yield a microphone performance that is flatter in the low and mid frequency areas and boosted in the high frequency area when compared to low impedance settings Ribbon microphones The impedance of a ribbon microphone is worthy of special mention as this type of microphone is affected enormously by pre amp impedance The ribbon impedance within this type of microphone is incredibly low around 0 20 and requires an output transformer to convert the extremely low voltage it can generate into a signal capable of being amplified by a pre amp The ribbon microphone output transformer requires a ratio of around 1 30 primary secondary to increase the ribbon voltage to a useful level and this transformer ratio also has the effect of increasing the output impedance of the mic to around 2000 at 1kHz This transformer impedance however is very dependent upon frequency it can almost double at some frequencies known as the resonance point a
14. ches on the front panel A 2 way switch labelled Power supplies power to the unit providing the supplied IEC mains lead is connected to the input on the rear panel Make sure that the ISA 828 is turned on before powering up any devices connected to the outputs The IEC mains lead supplied with the unit should have the correct moulded plug for your country The wiring colour code used Is For units shipped to the USA Canada Taiwan and Japan Live Black Neutral White Earth Green For units shipped to any other country Live Brown Neutral Blue Earth Green and Yellow Front Panel Switch Input metering to pre ADC when using Inserts for Instrument Inputs Inputs 1 4 external processing of Inputs H He p LA Power switch 70 Focusrite Oc e JO iO Controls for Inputs 1 8 Digital Options for optional card Input Stage Selects the gain of the input in stepped values of 10 Allows an additional 20dB of gain to be applied to a mic or line signal or sets the gain of the instrument to between 10 and 40dB Activates a gain range of 30 60 across the Gain stepped dial the default is 0 30 Phantom Power switch Meter in dBFS Inverts phase of signal Selects input impedance to 600 1k4 2k4 or 6k8 Ohms Activates a high pass filter Routes channel 2 of the ADC Input on the rear panel to the optional digital card instead of th
15. d using the ADC Input The 25 pin connector is wired as follows Pin out for TASCAM DB25 8 Channel Balanced Connector CE LE BE LE SE GE DE eb GCHGCHGCHGCHGCHGCHGCHGCH 50 4O BO 2O 2O WO 170 wO 50 O H HOT C COLD G GROUND Trim The dial labelled TRIM is for calibrating the front panel LED meters peak level The default state is with the knob in a central de tented position where the top red LED lights at 22dBu Rotating the knob will set the value between 18dBu fully anticlockwise and 26dBu fully clockwise IEC mains inlet This socket allows the supplied IEC cable to be connected to enable the 828 to be powered A fused voltage selector is also present with a diagram alongside to indicate the positions that relate to each voltage Optional digital card connections The remaining connections if present are those on the optional digital card and are explained fully in the next section Digital Options The optional ADC can be retrofitted to a standard ISA 828 at any time No engineering experience is required as the card can be fitted easily by the user Full fitting instructions for this option are included along with the ADC AES S PDIF Outputs 1 8 Selects AES switched out 25 pin D type or S PDIF pressed in Word Clock In and Out BNC connectors IWIRE JI AES 3 4 192 Hz 1 2 AES SPDIF 2VVIRE SPDIF 5 8 96k 4z 1 4 1 8 48k 4z 1 8 IN WORD CLOCK OU
16. e Audio Engineering Ltd ADAT is a registered trade mark of Alesis Corporation Inc Pro Tools and 192 HD are registered trademarks of Digidesign Inc Tascam is a registered trademark of TEAC Corporation Inc Appendix 1 Recording AES Outputs 1 8 to Pro Tools HD at 192kHz To record all eight channels digitally to Pro Tools HD at 192kHz all eight AES channels need to be enabled on the ISA 828 default jumper positions shown on Appendix 2 and 2 Digital cards must be fitted in the HD192 interface A 25 pin to two 25 pin cable must then be used with the following pinout s so sw w 5 e nes 20 Appendix 2 Digital Card Jumper Positions Disabling AES Outputs 5 8 Four jumpers on the digital card can be made to disable channels 5 8 on the AES Output This is so that a standard 25 pin to 25 pin Pro Tools cable can be used to record channels 1 4 at 192kHz Half of the connections on the Digidesign Digital Input are used for receiving and the other half for transmitting For more information consult the relevant section of the Pro Tools User Guide As shown on the card with the jumpers in the lower position on the bottom two pins outputs 5 8 are enabled Removing the jumpers and placing them in the upper position on the top two pins disables outputs 5 8 as shown AES Outputs 5 8 enabled qeu ridens AES Outputs 5 8 disabled Ne T DN
17. e direct mic line inst signal for input 2 Selects type of input Eight numbered sections are included on the front panel for setting up each of the eight analogue inputs Input Pressing Input steps through each of the three inputs as indicated by the corresponding LEDs When the Mic LED is lit the microphone input is active etc Hence a mixture of microphone line and instrument inputs may be selected across the eight channels simultaneously Note that only inputs 1 4 can be used for instruments however XLR inputs for microphones and TRS 1 4 inputs for line level sources are available on the rear panel TS 1 4 inputs for instruments are available on the front panel inputs 1 4 only Mic Input Gain With the Mic input selected the user has access to the full gain range in 10dB steps from OdB to 60dB yellow legend The gain range is split between two gain modes depending upon the status of the 30 60 switch see description on page 6 Mode 1 Mic Gain Range 0 30 With the 30 60 switch off the stepped gain dial operates over a gain range of OdB to 30dB the level of gain chosen being indicated on the front panel by the outer arc of yellow numbers around the gain knob Mode 2 Mic Gain Range 30 60 With the 30 60 switch on illuminated the stepped gain dial operates over a gain range of 30dB to 60dB the level of gain chosen being indicated on the front panel by the outer arc of yellow numbers around the gain knob An addi
18. nd tends to roll off to very small values at low and high frequencies Therefore as with the dynamic and condenser microphones the mic pre amp input impedance has a massive effect on the signal levels and frequency response of the ribbon microphone output transformer and thus the sound quality of the microphone It is recommended that a mic pre amp connected to a ribbon microphone should have an input impedance of at least 5 times the nominal microphone impedance For a ribbon microphone impedance of 300 to 1200 the input impedance of 6000 Low will work fine For 1200 to 2000 ribbon microphones the input impedance setting of 1 4 ISA 110 is recommended Impedance Setting Quick Guide In general the following selections will yield these results High mic pre amp impedance settings Will generate more overall level Will tend to make the low and mid frequency response of the microphone flatter Will improve the high frequency response of the microphone Low pre amp impedance settings Will reduce the microphone output level Will tend to emphasise the low and mid frequency presence peaks and resonant points of the microphone Signal Connections Recording from Analogue Outputs to the DAW DAW Interface Soundcard Synth Line out 4dBu lt Microphone Focusrite _ Recording with Inserts Focusrite Compounders Stereo Compression x 4 vm Qi 2 ADC INPUTS u Focusrite Digital Storage Medi
19. owing you to get improved ambient information and high end clarity even from average performance microphones Various microphone ISA 828 pre amp impedance combinations can be tried to achieve the desired amount of colouration for the instrument or voice being recorded To understand how to use the impedance selection creatively it may be useful to read the following section on how the microphone output impedance and the mic preamp input impedance interact Switchable Impedance In Depth Explanation Dynamic moving coil and condenser microphones Almost all professional dynamic and condenser microphones are designed to have a relatively low nominal output impedance of between 1500 and 3000 when measured at 1kHz Microphones are designed to have such low output impedance because the following advantages result They are less susceptible to noise pickup They can drive long cables without high frequency roll off due to cable capacitance The side effect of having such low output impedance is that the mic pre amp input impedance has a major effect on the output level of the microphone Low pre amp impedance loads down the microphone output voltage and emphasizes any frequency related variation in microphone output impedance Matching the mic pre amp resistance to the microphone output impedance e g making a pre amp input impedance 2000 to match 2000 microphone still reduces the microphone output and signal to noise ratio by 6dB which is undesira
20. ptional cable to use either of the A D cards A Yes Standard Tascam Pro Tools and ADAT optical cables are available from many sources 17 Specifications Mic Input Response e Gain range OdB to 60dB in 10dB steps e Input Impedance variable as follows Switched Impedance setting Equivalent Input Impedance at 1kHz o ISA 110 1400 Q Med Medium 24000 High 6800 Q EIN equivalent input noise 126dB measured at 60dB of gain with 150 Ohm terminating impedance and 22Hz 22kHz bandpass filter Noise at main output with gain at unity 0dB 97dBu measured with a 22Hz 22kHz bandpass filter e Signal to noise ratio relative to max headroom dBu 106dB e THD at medium gain 30dB 0 000896 measured with a 1kHz 20dBu input signal and with a 22Hz 22kHz bandpass filter e Frequency response at minimum gain 0dB 0 5dB down at 10Hz and 3dB down at 110kHz Frequency response at maximum gain 60dB 3dB down at 16Hz and 3dB down 85kHz e CMRR 1 8dB Channel 1 1kHz maxiumum gain e Crosstalk Channel to Channel with 10dBfa1kHz input to chA chB output 102dBrA With 10dB a10kHz input to chA chB output 84dBrA Line Input Response e Gain range 20dB to 10dB in 10dB steps Input Impedance 10kQ from 10Hz to 200kHz e Noise at main output with gain at unity 0dB 26dBu measured with a 22Hz 22kHz bandpass filter e Signal to noise ratio relative to max headroom 24dBu 120dB e Signal to noise ratio
21. r local dealer or in the UK from Studiospares tel 44 0 20 74821692 stock number 585 510 Word Clock In and Out The internal ADC can be synchronised to an external word clock By pressing the front panel Ext switch the synchronisation mode can be switched between standard external word clock and 256x external word clock Both types of external word clock should be connected to the ISA 828 ADC card at the Word Clock In BNC connector The Word Clock Out BNC connector either regenerates the external word clock connected at the Word Clock In BNC connector or transmits the internal sample frequency of the ADC card Where the ISA 828 is being used as a slave device within a larger digital system the Word Clock Out BNC connector can be used to pass on the external word clock signal to the next device When the unit is not slaved to another device and is in internal clock mode the Word Clock Out BNC connector outputs the sample frequency selected on the ISA 828 front panel Digital Output Front Panel Controls Selects sample rate Selects the ADC to lock to an external source connected to the word clock input on the rear panel either standard word clock or 256x Lock LED indicates when a successful synchronisation is achieved Clock Select Pressing this switch allows the user to select between sample frequencies of 44 1kHz 48kHz 88 2kHz 96kHz 176 4kHz and 192kHz Ext Select Pressing EXT allows the ISA 828 to be slaved to an
22. rear panel see description below therefore indicates that there is a signal level of 4dBu at the ADC input connector Meter Calibration A Trim dial on the rear panel allows the meters to be calibrated so that a different peak level is set See the TRIM section on page 9 for details Instrument Inputs Instrument sources may only be connected via the front panel Four unbalanced Instrument input connectors are located to the far left of the front panel and are numbered 1 4 relating to analogue inputs 1 4 These connectors are used primarily for connecting low level unbalanced signals such as those from passive guitars and basses or from active instruments such as keyboards and electro acoustic guitars The high and low impedance settings available on the instrument input allow a better match to be achieved with different output impedances of various instruments All 1 4 unbalanced jack connections are wired as follows Tip Audio 0 Sleeve Screen Chassis Sample rate and clock select The last section allows the sample rate and clock source of the digital output card if fitted to be selected See the Digital Options section on page 10 for details Rear Panel TRIM dial Calibrates the ADC Inputs 1 8 25 pin D type meters on the front panel each input is activated by Insert switches on the front panel Optional digital card connections Analogue Inputs ADC INPUTS 7 5 METER 2W
23. relative to OdBFS 22dBu 118dB e THD at unity gain 04 0 001 measured with a OdBu input signal and with a 22Hz 22kHz bandpass filter Frequency Response at unity gain 0dB 0 3dB down at 10Hz and 3dB down at 122kHz Instrument Input Response Gain range 10dB to 40dB continuously variable e Input Impedance High gt 1MQ Low gt 300kQ e Noise at minimum gain 10dB 90dBu measured with a 22Hz 22kHz bandpass filter e Noise at maximum gain 40dB 62dBu measured with a 22Hz 22kHz bandpass filter e THD at minimum gain 10dB 0 002 measured with a 10dBu input signal and with a 22Hz 22kHz bandpass filter e Frequency Response at 10dB gain with 10dB input 10Hz 200kHz 0 6dB e Frequency Response at 40dB gain with 40dB input 2 5dB down at 10Hz and OdB at 200kHz High Pass Filter Roll off 18dB per octave 3 pole filter e Fixed Frequency 75Hz measured at the 3dB down point Input Meter e Calibrated in the detent position for OdBFS 22dBu and indicates the level after the High Pass Filter and before the Insert Send output LED levels are as follows 0 22dBu 2 20dBu 6 16dBu 12 10dBu 18 4dBu 42 20dBu Calibration is adjustable to allow OdBFS to equal 10dBu to 26dBu 18 Warranty All Focusrite products are covered by a warranty against manufacturing defects in material or craftsmanship for a period of one year from the date of purchase Focusrite in the UK or its authorised distribu
24. s the specification of the A D option A AES both single and dual wire specs S PDIF and ADAT formats sample rates selectable between 44 1 48 88 2 96 176 4 and 192kHz ADAT above 48kHz is of course via 2 ports internal or external word clock and 256X clock S N Ratio better than 121dBFS A weighted to AES17 Connections are via a 25 pin D type connector and standard lightpipes word clock is via BNC in and out Q Does the ISA 828 s A D option feature word clock as standard A Yes word clock may be fed in via a BNC connector on each A D to allow the 828 to synchronise to any word clock master source Q Why do I need word clock anyway A When using multiple pieces of digital equipment it is necessary to make sure that their bit streams are all in sync In order to do this all equipment needs to be synchronized to a common word clock system Somewhere in this system a word clock master must be dictating the word clock for the rest of the equipment word clock slaves to follow Failure to sync all pieces of digital equipment to a common word clock source will result in audible clicks and glitches in programme material Note that the 828 regenerates word clock at its BNC output further boosting word clock stability Q How many rack spaces does ISA 828 take up A The ISA 828 is a 2U device Q What rear panel connections are featured A The ISA 828 has 8 XLRs for connecting microphones and 8 1 4 TRS Jack line
25. tional 20dB of gain can be applied to the signal after the mic line Gain knob using the Trim knob See the Trim control text below for a full explanation Line Input Gain With the line input selected the user has access to gain settings ranging from 20dB to 10dB indicated on the front panel by the arc of white numbers around the gain knob The 30 60 switch is inactive when the line input is selected as the gain range for Line level inputs is restricted to 20dB to 10dB in 10dB steps An additional 20dB of gain can be applied to the signal after the mic line gain knob using the Trim knob See the Trim control text below for a full explanation Instrument Input Gain With the instrument input selected inputs 1 4 only gain is applied to the input signal by using the trim control only which allows 10dB to 40dB of gain range The level of gain chosen is indicated on the front panel by the outer arc of yellow numbers around the gain knob This input is suitable for high impedance sources such as guitar or bass pickups which may be connected directly without the need for an external DI box or vintage synthesizers with high impedance outputs Trim The Trim control provides additional variable gain of OdB to 20dB when mic or line inputs are selected The level of gain chosen is indicated on the front panel by the inner arc of white numbers around the gain knob The additional 20dB of gain that can be applied to the mic or line
26. tors worldwide will do their best to ensure that any fault is remedied as quickly as possible This warranty is in addition to your statutory rights This warranty does not cover any of the following Carriage to and from the dealer or factory for inspection or repair Labour charge if repaired other than by the distributor in the country of purchase or Focusrite in the UK Consequential loss or damage direct or indirect of any kind however caused Any damage or faults caused by abuse negligence improper operation storage or maintenance If a product is faulty please first contact the dealer from which the product was purchased If the product is to be shipped back please ensure that it is packed correctly preferably in the original packing materials We will do our best to remedy the fault as quickly as possible Please help us to serve you better by completing and returning the Warranty Registration Card or registering online at http www focusrite com Thank you Accuracy Whilst every effort has been made to ensure the accuracy and content of this manual Focusrite Audio Engineering Ltd makes no representations or warranties regarding the contents Copyright 2007 2008 Focusrite Audio Engineering Ltd All rights reserved No part of this manual may be reproduced photocopied stored on a retrieval system transmitted or passed to a third party by any means or in any form without the express prior consent of Focusrit
27. um Recording from AES Outputs 1 8 to Pro Tools HD at 192kHz Pro Tools HDTM 192 Interface AES EBU 25 pin Inputs requires 2 cards Word Clock Output 1x or 256x ANALOGU Cable pinout according to Appendix 1 ISA 828 Digital Card in 2 wire mode Jumpers in default enabled position FAQs Q What are the basic features of the ISA 828 A Eight Focusrite mic pres eight line inputs four instrument inputs optional 8 channel 192kHz A D conversion Q Which applications is the ISA 828 suitable for A The ISA 828 can be used as a multi channel high quality front end for Digital Audio Workstations allowing multi channel recording to HD Equally it can be used simply as the perfect interface or A D converter for synths other line level devices It also provides additional channels for anyone who has run out of mic pres on their analogue console either live or recording and is especially useful as a source of additional mic pres for digital consoles Q Which Focusrite pre is featured in the ISA 828 A It s the original transformer balanced mic pre that featured in the classic analogue Focusrite consoles in the 1980s This is also the classic pre that features in the ISA 430 MKII and 428 Q Do the pres have the usual phantom power and High Pass Filter controls A Yes and more each pre has switchable mic impedance so that you can match to your chosen mic s impedance or mismatch for cre
28. upply unit contains no user serviceable parts Refer all servicing to a qualified service engineer through the appropriate Focusrite dealer Contents Getting Started and Powering Up 4 Front Panel 5 Rear Panel 8 Digital Options 10 Applications 12 FAOS 16 Specifications 18 Warranty 19 Mode d emploi 22 Getting Started and Powering Up The ISA 828 is a high quality eight channel microphone preamplifier which can be used to record microphone line level or instrument sources Microphones and line level sources for all eight inputs are connected on the rear panel whilst instruments are plugged directly into the front panel inputs 1 4 only The front panel also features level controls and other settings such as phantom power and impedance for each of the eight analogue inputs LED metering is provided on each channel in dBFS to indicate when the level is reaching the digital clipping point with a dial on the rear panel for calibration If wanting to maintain pristine Focusrite quality in the digital domain an optional digital output card can be installed for connecting an AES S PDIF or ADAT signal directly to the DAW With the card fitted the clock sample rate and sync source can be selected with swit
29. urate the final signal will be compared to the original The greater the sample rate and bit rate the more accurate the whole digital process is So 24 bit 192kHz performance will ensure more accurate digital transfer of your audio information compared to the old 16 bit 44 1kHz standards This is especially important if further digital signal processing is to be applied to the signal once converted to digital as any mathematical operations taking place on the data as a result of a gain change or dynamic effect process for example may result in quantization and rounding errors The higher the resolution of the digital data the smaller the audible effect of these errors Q How many digital outputs can use at the same time A It depends on which sample rate you choose At 48kHz or lower 8 AES and S PDIF 2 x 8 ADAT max 32 outputs simultaneously At 96kHz 8 AES and S PDIF 8 ADAT max 24 outputs simultaneously At 192kHz 8 AES and S PDIF 4 ADAT max 20 outputs simultaneously Both AES single wire and split wire configurations are supported split wire will obviously reduce the maximum number of simultaneous outputs ADAT SMUXIV supports sample rates above 96kHz only channels 1 4 are available at 176 4kHz amp 192kHz Q When the A D is used are my analogue outputs available for use A Yes The 8 line outputs can run simultaneously with all of the ADAT AES or S PDIF outputs Q Do need to buy an o
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