prismsound DA-2 - Test and Measurement
Contents
1. 15 6 3 Connectortable 16 7 SPECIFICATION ia AAA 17 Ae Digital InpUls AA qase eoa hc eva 17 fad Se lie id ie kean OR N N IA Soe tae eU 20 7 3 Digital Outputs 21 7 4 Analogue Outputs 24 7 5 Performance Specification 25 1 6 PONELIS RE iia Secs et texto na a aT Ena ate teste e EN EHE 27 Tuli Physical DIMGNSIONS ss ese EERDER SR AAA AAA 27 8 INTERNAL CONFIGURATION OPTIONS AND FUSES 28 Colle EE ME AR EER ME eating OR es 28 0 2 FEB IUMDEFIRKE SR GOS OE AS OER Paes eee SES 28 8 3 Mains transformer voltage selection 29 Issue 1 0 Prism Media Products Limited 25 August 1998 Page 2 of 30 Prism Media Products Limited Dream 2 4 2 Operation Manual 9 ELECTROMAGNETIC COMPATIBILITY 29 10 REFERENCES mii 30 Manual Revision History 25 August 1998 Issue 1 0 Original Issue Product Revision History August 1998 Hardware revision A Prism Media Products Limited William James House Cowley Road Cambridge CB4 4WX UK Phone 44 0 1223 424988 Fax 44 0 1223 425023 Email tech support prismsound com Web http www prismsound com Issue 1 0 Prism Media Products Limited 25 August 1998 Page 3 of 30 Prism Media Products Limited Dream 2 4 2 Operation Manual 1 INTRODUCTION2. 4 4 2 Master mode sampling rate selection DI Source In Set Master mode if the DA 2 is Select N AES8 opt RA Boso Configured as a clock master then the DIT Di2 DIB Di4 DI5 DI6 DIT e o gt o ee e e sampling frequency can be changed by pressing the Select button 4 2 1 12 18 22 28 Rate This action cycles between the available sample rates which are displayed by 48kHz the 32kHz 44 1kHz and 48kHz LEDs and also the X2 LED which is used HIKO to qualify 88 2kHz and 96kHz modes If not configured as clock master then the gie Select button has no effect NOTE 64kHz sampling is not supported Mastori P Press SET to leave Set Master mode and return to normal mode Issue 1 0 Prism Media Products Limited 25 August 1998 Page 12 of 30 Prism Media Products Limited Dream 2 2 Operation Manual 5 FRONT PANEL INDICATORS 5 1 Input selection or maximum output level setting indicators The horizontal bank of seven green LEDs on the left side of the front panel performs three functions 5 1 1 Selected input indication In Normal mode the SET control not illuminated one of the LEDs will be illuminated to show the currently selected input It will flash if that input is not present or is incorrect On receipt of single errors it will briefly extinguish In certain special modes more than one indicator may be lit as follows C Split96 2 wire mode for inputs 2 amp 3 see section 4 2 1
3. 40kHz 3dB fs 88 2kHz 5 Hz 31 7 kHz 0 05 dB 0 1Hz 37kHz 3dB Note relaxed roll off filters are deliberately specified for 88 2kHz and 96kHz operation to minimize audio band time domain dispersion effects pre and post echoes Stop band Begins at fs 2 for all sampling rates Group delay fs 96 kHz 34 5 samples 0 36 ms fs 88 2 kHz 37 samples 0 42 ms fs 48 kHz 61 5 samples 1 28 ms fs 44 1 kHz 63 3 samples 1 44 ms fs 32 kHz 63 3 samples 1 98 ms Phase linearity error 0 8E within the following frequency ranges 5 Hz 22kHz fs 96 kHz 5 Hz 20kHz fs 88 2 kHz 5 Hz 20kHz fs 48 kHz 5 Hz 18kHz fs 44 1 kHz 1 6E over 2 5 Hz 20 kHz 5 Hz 15kHz fs 32 kHz Inter channel phase deviation without de emphasis lt 0 5E with de emphasis 0 5E Issue 1 0 Prism Media Products Limited 25 August 1998 Page 25 of 30 Prism Media Products Limited 2 Operation Manual Absolute phase Correct unless nvert function on Note Unless invert is on negative digital inputs produce a negative analogue output This makes the pin 2 of the output connector negative with respect to pin 3 This is in accordance with the standards IEC268 12 1969 and AES14 Crosstalk 100 dB 20 Hz to 20 kHz Sampling jitter rejection High precision clock used if clock within 0 1596 of standard frequencies Jitter attenuation slope 80dB per decade Corner frequency approx 80Hz Attenuation above 500Hz gt
4. 60dB Wide range clock used if clock outside normal frequency tolerances Jitter attenuation slope 40dB per decade Corner frequency approx 800 Hz Attenuation above 8kHz gt 30dB Maximum output signal level Gain is adjustable so that the output level for OdB FS full scale input can be preset from 5 dBu to 28 dBu in 1dB steps with fine trim in steps of 0 05dB At sample rates below 44kHz the maximum level is 25dBu This is made up from four analogue gain settings corresponding to 12 dBu 18 dBu 22 dBu 28 dBu and a variable attenuation in the digital domain As the digital attenuator reduces the maximum level without lowering the noise floor it has the effect of lowering the dynamic range For optimum dynamic range the digital attenuation should be minimised The digital attenuation is inactive at level settings of 12 dBu 18 dBu 22 dBu and 28 dBu For samples rates below 44kHz the four analogue gain settings are 3dB lower so the digital attenuation is inactive at settings of 9dBu 15dBu 19dBu and 25dBu However the final gain is shown correctly unless the gain is set to more than the maximum of 25dBu Gain error lt 0 05 dB for all settings Gain trim step size 0 05 dB Level dependent logarithmic gain linearity lt lt 3dB at 144dB FS Note This is a measurement of the output level of a 996 115Hz tone with respect to the input level The output level at 997Hz is measured using 32 averages of an 8192 point F
5. The Dream DA 2 is a 24 bit 96KHz capable digital to analogue converter intended for professional audio use in applications where a very high performance is required for monitoring for example in the production of high quality masters or for conditions such as live recording where a large headroom may be required The Prism Sound Dynamic Range Enhancement DRE system is also incorporated for use in monitoring and or decoding a DRE encoded source 2 SUMMARY OF DA 2 FEATURES e 24 bit input resolution Sampling rates to 96kHz 114 dB A weighted dynamic range Less than 104 dB THD N at full scale 0 000696 Flat low frequency response 0 05 dB at 5 0 Hz Floating balanced outputs Calibrated maximum output level adjustment 5 dBu to 28 dBu in 1 dB steps Fine trim in steps of 0 05dB DRE decoding to analogue and digital outputs e Input selection from seven stereo inputs Digital inputs in AES3 AES3 Split96 SPDIF Optical AES 3ID coax and SDIF 2 formats e Digital outputs in AES3 SPDIF Optical and SDIF 2 formats simultaneously also AES3 Split96 capability e Digital interface format conversion Mute control on front panel e Invert control on front panel De emphasis of emphasised signals Both CD and J17 characteristics e Low jitter high precision clock with Capture range better than IEC958 specification 1500ppm Excellent jitter tolerance gt 200ns at 2kHz Excellent jitter rejection 60dB at
6. Internally set for 90 120V nominally 110V or 195 250V nominally 230V operation The supply voltage is indicated on the rear panel 7 6 2 Consumption 30W 7 7 Physical Dimensions Weight 8 8 Ib 4 Kg Width 19 inch 483mm rack mountable Height 1U 44mm Depth 10 25 inches 260mm Issue 1 0 Prism Media Products Limited 25 August 1998 Page 27 of 30 Prism Media Products Limited Dream 2 4 2 Operation Manual 8 INTERNAL CONFIGURATION OPTIONS AND FUSES Other than the external mains fuse the following parts can only be accessed by removing the equipment top cover This should only be undertaken by qualified personnel There are no user serviceable parts inside this unit 8 1 Fuses There is one mains fuse in the IEC320 mains inlet If this fuse is blown it should be replaced by a similar value and type 20x5mm 250V 2AT anti surge There are seven fuses internal to the unit If these fuses have blown a fault has occurred and the unit should be returned to the manufacturer or agent for service The fuse types and application are F1 Digital processing input and output Type 2AT Wickman TR5 subminiature type no 19372K 2A F5 F6 F7 F9 Analogue output channel A F2 F3 F4 F8 Analogue output channel B Type 0 5AT Wickman TR5 subminiature type no 19372K 500mA 8 2 PCB jumper links Factory setting Main board PREVO51 1 Option select not used No links fitted Not fitted Not fitted Future compat
7. Manual 7 2 2 Clock master synchronization Clock accuracy 10 ppm Reference to input timing variation from ideal before sample slip 75 of sample period Sample slip hysteresis 50 of sample period Note The AES11 1991 synchronization standard 2 requires an input synchronization window of 25 of a sample period without hysteresis The Dream DA 2 exceeds this specification This is to allow it to work properly with equipment that does not conform with the AES11 standard This hysteresis avoids the possibility of repeated sample slips which can occur as a result of small timing variations about some static offset 7 3 Digital Outputs The digital outputs provide the same audio data as present on the selected digital input except when DRE decode is active The output channel status data is not copied from the input but is regenerated by translating from the input format to the output format This means that the various output connectors always have the appropriate data format for the connector style NOTE The input format is determined by the data content at the input and not the connector Therefore when connecting an AES3 data format but consumer SPDIF electrical format signal to the RCA coaxial input then the signal channel status format will be translated to consumer format at the RCA coaxial output and remain in professional format at the XLR output This means that the Dream D 2 is also a digital audio format converter and
8. corrector 7 3 1 Jitter characteristics common to all digital outputs Jitter peaking less than 1dB in both ranges High precision clock Jitter attenuation slope 80dB per decade Corner frequency approx 80Hz Attenuation above 500Hz gt 60dB Wide range clock Jitter attenuation slope 40dB per decade Corner frequency approx 2 kHz Attenuation above 8kHz gt 24dB Intrinsic jitter lt 0 005 Ul pk pk sins at fs 44 1kHz Note Intrinsic jitter is measured using a low frequency cut off of 200Hz see references 5 and 6 for a more detailed explanation of these interface jitter parameters Issue 1 0 Prism Media Products Limited 25 August 1998 Page 21 of 30 Prism Media Products Limited A 2 Operation Manual 7 3 2 Audio data on digital outputs Unless the DRE decoder function is operating all the audio data on the input is passed through to the digital outputs without modification However the SDIF 2 output is limited to a maximum of 20 bits If the DRE decoder function is on then the digital output word length is 18 bits Note To avoid truncation distortion care must always be taken to match the signal word length to the input word length of following equipment If the DA 2 is passing through 24 bit data then truncation distortion will occur in the signal at the SDIF 2 outputs Often equipment is limited to a 16 bit input resolution and further truncation will occur at that equipment if the signal is not re dithered T
9. disabled using 4 2 1 12 18 22 28 MUTE Inputs Inputs DI2 and DI3 the second and third AES3 XLR inputs can be configured as a Split96 input see below If configured for Split96 operation when selecting inputs for enabling or disabling the indicators for DI2 and DIS will operate together 4 2 1 Split96 Sources vure ry Once in SET Inputs mode see above press TER the NV Split96 button to change the mode of aster Inputs Level Split96 inputs 2 and 3 for either Split96 2 wire or normal 1 wire operation Issue 1 0 Prism Media Products Limited 25 August 1998 Page 9 of 30 Prism Media Products Limited Dream 2 4 2 Operation Manual In Split96 mode two AES3 bearers both at 44 1kHz or 48kHz carry a stereo 88 2kHz or 96kHz sampled signal with one channel carried on each bearer as described in ref 8 Split96 or 2 wire AES sources may only be connected to Inputs 2 amp 3 Split96 mode for DI2 amp DI3 only is indicated once in Set Inputs mode by the NV Split96 LED being ON Thereafter inputs DI2 and DIS are treated as a Split96 pair unless the INV Level Split96 button is used again to separate them this is irrespective of the mode expressed in the channel status In Split96 mode input 2 carries the left channel and input 3 carries the right channel Split96 mode is only available on inputs 2 amp 3 and the Split96 indication does not change while in SET Inputs mod
10. is reduced by 5dB compared with the 18dBu setting Issue 1 0 Prism Media Products Limited 25 August 1998 Page 11 of 30 Prism Media Products Limited Dream 2 2 Operation Manual Press SET to leave Set Level mode and return to normal mode 4 4 Set Master mode Set Master mode is used to set the DA 2 to be clock master and change the sample rate it uses when master As a clock master the DA 2 requires incoming data to be synchronized to the DA 2 internal clock Any of the DA 2 digital outputs can be used as a synchronization reference to the source of the data To enter Set Master mode the DA 2 must first be DRE in normal mode i e if the SET control is not already illuminated While holding the SET nputs Level Master Split96 button down press the DRE Masterbutton This mode is indicated by both the DRE Master and the SET LEDs being lit 4 4 1 Setting master or slave synchronization Rate 48kHz 44 1KHzZ 32kHz x20 Master 0 In Set Master mode pressing the DRE Master button toggles between master internal and external synchronization This is indicated by the amber Master light situated beneath the frequency lights at the left of the front panel If this light is on then the DA 2 is synchronized to a precise free running internal oscillator otherwise it is synchronized externally If it is flashing then one of two error states is indicated as described in section 5 4
11. jitter remover 3 4 Dynamic Range Enhancement DRE DRE is a process designed for the increasing the dynamic range of 16 bit recording channels such as DAT CD R or 1630 U matic when further post processing is required It requires an encode process on recording and a decode process on playback It is suitable for applications where 20 bit dynamic performance is desired of the recorder but only a 16 bit recorder is available and where the requirement for a decode process is acceptable The Prism Sound Dream AD 2 and AD 124 analogue to digital converters can encode DRE signals from digital or analogue sources and can also decode them in digital to digital mode to transfer the high resolution signal encoded on a 16 bit tape onto a 20 bit digital audio workstation The Dream can be used with the AD 2 or AD 124 to provide analogue monitoring of the encoded signal as well as to perform the digital to digital decoding function required for transfers to the linear or non DRE domain Issue 1 0 Prism Media Products Limited 25 August 1998 Page 7 of 30 Prism Media Products Limited Dream 2 2 Operation Manual 4 OPERATION There are five control buttons In normal use they operate in isolation to Se ect the digital source MUTE the output NVert the output and turn on the DRE decode function When setting up the unit the configuration settings which are intended to be set and then left alone can be modified from one of
12. return all the DA 2 settings to the factory defaults then switch the unit on Issue 1 0 Prism Media Products Limited 25 August 1998 Page 6 of 30 Prism Media Products Limited 2 Operation Manual while pressing all four of the right hand buttons during the whole of the start up cycle this takes approximately ten seconds In the default configuration the indicators for the four right hand side controls should not be on If the set button indicator is on then press the button to leave set mode If any of the other control button indicators are on then press the respective control buttons to toggle them off If you are still having problems setting the unit into the standard configuration described above then refer to the descriptions of the set inputs section 4 2 or set master section 4 4 controls 3 3 DA 2 product concept and capabilities The Dream DA 2 is designed to provide a very high quality of digital to analogue conversion without sampling jitter or data truncation whatever the resolution or timing accuracy of the source Two other useful features are also provided These are a set of jitter filtered digital outputs and a Dynamic Range Enhancement DRE decoder The digital outputs normally provide the same data as present on the selected digital input translated into the appropriate format and any incoming jitter is filtered off This means that the Dream DA is also a digital audio format converter corrector and
13. the screen connecting to the chassis of the analogue input The DA 2 should be connected to an unbalanced input using only pins 1 and 2 of the output XLR Pin 2 should connect to the signal input and pin 1 should connect to the input ground Using this method the signal level is half the nominal value NOTE It is possible to drive unbalanced inputs from pins 2 and 3 of the DA 2 analogue output but because the connection has been unbalanced this will give slightly worse performance However if the output is connected in that way it is important that pin 1 is not connected at the unbalanced input end as this will short circuit one leg of the floating output driver 6 2 Interconnect screens the pin 1 conditions Screen connects directly to the chassis for the digital XLR and BNC connectors The RCA digital coaxial connections are transformer isolated with the screen coupled to the chassis using a capacitor at the connector The analogue output screens are the mid points of the floating differential outputs They are coupled to the chassis using a capacitor from pin 1 to the chassis Issue 1 0 Prism Media Products Limited 25 August 1998 Page 15 of 30 Prism Media Products Limited Dream DA 2 Operation Manual 6 3 Connector table Viewed from the rear the connectors are as follows LeftHand Side iEC3o0 Mains powerinet Analogue Outputs Analogue out right B XLR Female DI2 AES3 Left channel for Split96 2 wir
14. the three set modes Set Inputs Set Level and Set Master The SET button is illuminated to indicate one of these modes All the control settings are saved in permanent memory so that they are retained when the unit is off 4 1 Normal mode controls The following functions apply to the MUTE MUTE INV fore INV and DRE controls only if the SET control is off This indicates normal mode npuS ONA p Vaier and is the power on state Split96 4 1 1 MUTE This mutes the analogue output Digital outputs are unaffected 4 1 2 INV This inverts the polarity of both analogue outputs Digital outputs are unaffected 4 1 3 DRE This control is used to switch on the DRE decoding function on the digital input DRE is described in section 3 4 Both the analogue and digital outputs are affected by this control 4 1 4 Select input vm Pressing this button causes the Select lt AES OT RCA NCISOF selected digital input to switch to eee ee oo the next enabled input see section 4 2 NOTE If this control does not seem to operate correctly it may be because some inputs have been disabled Refer to the description of the Set Inputs control section 4 2 to change this Issue 1 0 Prism Media Products Limited 25 August 1998 Page 8 of 30 Prism Media Products Limited Dream 2 2 Operation Manual 4 1 5 SET Holding this button down while pressing one of the three adjacent switches puts the unit i
15. 2 4 2 Operation Manual Pin 1 of the XLR connector is connected to the chassis via a capacitor and the signal is presented differentially across pins 2 and 3 NOTE XLR inputs 2 and 3 may be jointly configured as a Split96 input allowing stereo 88 2kHz and 96kHz sampled inputs with one channel on each bearer This format is described in ref 8 7 1 3 Optical input D14 This input is physically compatible with the Toshiba TosLink fibre optic connector and data encoded according to professional AES3 1992 or consumer IEC958 formats is correctly decoded 7 1 4 Coaxial RCA consumer input DI5 Input impedance 75S This conforms to the coaxial specification of IEC958 and for improved isolation has transformer isolation with the screen capacitatively coupled to the chassis Data encoded according to professional AES3 1992 or consumer IEC958 formats is correctly decoded 7 1 5 Dual function coaxial BNC professional inputs DI6 DI7 Input impedance 75S The connectors either operate as coaxial AES3 AES 3ID or SDIF 2 inputs An auto detection algorithm decides which format to use as follows If the unit is in clock master mode Master light on If a valid SDIF signal is detected on the selected input then both inputs will be treated as SDIF 2 format If a valid AES or IEC958 signal is detected on the selected input then that input will be decoded as that format Otherwise if the unit is not in clock master mod
16. 500Hz e Clock master mode Issue 1 0 Prism Media Products Limited 25 August 1998 Page 4 of 30 Prism Media Products Limited Dream 2 4 2 Operation Manual 3 GETTING STARTED It is not necessary to read all the manual before being able to use the Dream DA 2 This section contains all the information required for you to get going straight away 3 1 Unpacking your DA 2 Check that you have the following items and that they are undamaged Dream DA converter unit Dream operation manual this book IEC320 type mains lead with appropriate plug for your supply Check that your unit carries a label on the rear panel indicating the correct mains voltage for your application area and that the plug fitted to the mains lead is of the correct type If not DO NOT CONNECT THE MAINS SUPPLY but contact your distributor Please keep the packaging for re use in the event that the unit should be shipped to another location or in the event that it should ever need to be returned to the manufacturer for repair or upgrade 3 2 Using the DA 2 for the first time Connect a digital audio source to one of the inputs on the DA 2 3 2 1 AES or SPDIF sources Source equipment operating at any of the standard rates from 32kHz to 96kHz may be connected to any of the inputs including the BNC connectors 3 2 2 Higher sampling rate sources using Split96 or 2 wire format For Split96 2 wire sources you must use inputs 2 and 3 in the DA 2 Split9
17. 6 mode as only these inputs can handle this format Input 2 will be routed to the left output channel and Input 3 will be routed to the right channel 3 2 3 SDIF 2 format If the source is in the Sony Digital Interface Format SDIF 2 then the three BNC inputs labelled L R and WCK need to be used The L amp R inputs are dual function and auto sensing so SDIF 2 AES3 ID and SPDIF signals can be connected Note For more information about configuration of DA 2 inputs refer to section 4 2 Issue 1 0 Prism Media Products Limited 25 August 1998 Page 5 of 30 Prism Media Products Limited A 2 Operation Manual 3 2 4 Output connector wiring The analogue outputs of the DA 2 are wired as follows pin 1 Screen and mid point of balanced output pin 2 Balanced output Hot or pin 3 Balanced output Cold or Conventional connections to a balanced analogue input should use a screened twisted pair lead The DA 2 output pins 2 and 3 should be wired to the two conductors of the pair and pin 1 to the cable screen The other end of the cable should be connected in a similar manner 3 2 5 Connecting the DA 2 to unbalanced inputs For optimum performance the DA 2 should be connected to an unbalanced input using only pins 1 and 2 Pin 2 should connect to the signal conductor and pin 1 should connect to the ground or return The signal level is then halved NOTE Use of output pin 3 instead of 2 will result in phase inversion I
18. Dream Seres da Professional D A converter Operation Manual Issue 1 0 25 August 1998 M Vi WSN A nfl Consultant engineers fm DSP real tie contro Prism Media Products Limited Dream 2 4 2 Operation Manual CONTENTS 1 INTRODUCTION S Soi ER EE e er a plo an Sok el die oe eed 4 2 SUMMARY OF DA 2 FEATURES 4 3 GETIINGSTABTED SS x ueri oad r AA E Ue 5 3 1 Unpacking your DA 2 5 3 2 Using the DA 2 for the first time 5 3 3 DA 2 product concept and capabilities 7 3 4 Dynamic Range Enhancement DRE 7 4 OPERATION aiea turae Ra EE E cU Mn oui E US GER QUAM ACRAS T eens 8 4 1 Normal mode controls 8 4 2 Setinpuismode 9 43 ebbevel mode AA Ata AA AA AAA VR WE WE 11 44 SetMastermode 12 5 FRONT PANEL INDICATORS 13 5 1 Input selection or maximum output level setting indicators 13 5 2 32kHz 44 1kHz and 48kHz indicators 13 53 X2 MGIC OR scettr neat Ip ed WAWA uv aig sale oad ML ML Mu 14 5 4 Master indicator 14 6 CONNECTORS UA IAA 15 6 1 Analogue output connectors 15 6 2 Interconnect screens the pin 1 conditions
19. FT with a rectangular window This method has much higher resolution than the test in AES17 which specifies a third octave band pass filter to eliminate noise Even so the signal level measurements are still dominated by the noise floor at 144dB FS Issue 1 0 Prism Media Products Limited 25 August 1998 Page 26 of 30 Prism Media Products Limited Dream 2 4 2 Operation Manual Harmonic distortion and noise 104dB 997 Hz at 1dB FS Intermodulation distortion 90dB Note The intermodulation test from AES17 uses 18kHz and 20kHz signals at 6 03dB FS each The result is the ratio of the total output rms signal level to the rms sum of the 2nd and 3rd order modulation products at 2kHz and 16kHz Dynamic range or signal to noise ratio gt 111dB CCIR RMS gt 114dB A weighted RMS gt 111dB unweighted RMS Note Measured at output settings of 18 22 and 28dBu at a level of 60 dB FS Idle channel noise lt 111dB FS CCIR RMS 114dB FS A weighted RMS lt 111dB FS unweighted RMS Note Measured at output settings of 418 422 and 28dBu All Spurious levels lt 110dBFS full scale signals 125dBFS signals below 20dBFS lt 131dBFS signals below 60dBFS Note Highest level of any spurious frequency component including harmonic components Aharmonic spurious levels lt 125dBFS full scale signals Note Highest level of any spurious frequency component excluding harmonic components 7 6 Power 7 6 1 Mains voltage
20. and section 7 1 2 C SDIF 2 format using inputs 6 amp 7 see section 7 1 5 5 1 2 Enabled inputs indication In Set Inputs mode the SET and nputs controls being illuminated the LEDs corresponding to the enabled inputs will be illuminated The LEDs corresponding to the disabled inputs will be off One LED will be flashing to indicate the input that will be enabled or disabled if the nputs control is pressed See section 4 2 5 1 3 Peak output level indication In Set Level mode the SET and Level controls being illuminated the LEDs give an indication of the output level corresponding to peak code This level in dBu is calculated from the sum of the illuminated LEDs When connecting to an unbalanced input as described in section 3 2 5 7 4 1 the output level is 6dB less than this value For example 20dBu is shown by only the 22 and 2 LEDs being illuminated 28dBu is shown by only the 28 LED being illuminated A typical consumer unbalanced level of 8dBu which is equivalent to balanced 14dBu needs to be indicated by the 18 and 4 LEDs being indicated 5 2 32kHz 44 1kHz and 48kHz indicators If the operating sample rate is within the capture range of the high precision PLL then one of these indicators will indicate the sampling frequency possibly in conjunction with the X2 indicator to show 88 2kHz or 96kHz operation as described in the following section The appropriate indicator s will flash if the unit has lost the so
21. by 6dB 4 3 1 Setting the maximum output level DI Source To set the maximum output level press As opt Ra Becso the Select button repeatedly until the o DIt DI2 DIS Did DI5 DI6 DIT eee ee ee desired level is reached 4 2 1 12 18 22 28 Each press will raise the level by 1dB until 28dBu beyond which the level will return to 5dBu 4 3 2 Fine output level adjustment To make a fine level adjustment hold down the NV Level control while pressing the Select button Each time Select is pressed a level adjustment of 0 05dB is applied until 0 95dB beyond which the trim returns to zero The trim value is not displayed If the trim is active NV Level will flash when in Set Level mode The fine trim can be cleared by pressing the Select button once in Set Level mode The INV Level LED will then cease flashing and remain lit Subsequent operations of Select will apply the normal 1dB gain step for setting the maximum output level Note that the best dynamic range is achieved when one of the standard levels 12 18 22 28 is used and the other LEDs 4 2 1 are not illuminated The latter LEDs show the amount of digital attenuation that has been applied As this attenuation lowers the maximum level but not the noise floor it reduces the dynamic range by that amount For example with a level setting of 13 dBu the analogue level is set to 18dBu with a digital attenuation of 5dBu Therefore the dynamic range
22. e Master light off If a valid word clock signal is present on the WCK input then both inputs will be treated as SDIF 2 format Without a valid WCK then any signal on the selected input will be treated as AES3 or IEC958 format Issue 1 0 Prism Media Products Limited 25 August 1998 Page 18 of 30 Prism Media Products Limited 2 Operation Manual 7 1 5 1 DI6 DI7 operating as AES3 or IEC958 format inputs These conform to the AES 3ID recommendation Ref 7 However data encoded according to professional AES3 1992 or consumer IEC958 formats is correctly decoded 7 1 5 2 DI6 DI7 operating as SDIF 2 Sony format inputs The input selection indicators for DI6 and DI7 both illuminate if the inputs are being handled in this format If one of the inputs is not present then that indicator will flash In this mode the inputs conform with the interfaces initially used by the Sony PCM 1610 1630 PCM encoder The signal on DI6 is the left channel and on DI7 is the right channel Note Signals in this format are D C coupled at TTL levels and transmitted most significant bit MSB first in non return to zero NRZ format A synchronization pattern identifies the start of a new sample word Some implementations of this interface do not use the synchronization pattern to identify the sample word boundary Such equipment will often require delays to be carefully matched before they will work correctly The Dream DA 2 uses a rugged algorithm
23. e 96kHz XLR Female DI3 AES3 Right channel for Split96 2 wire 96kHz OPTICAL Digital DI4 IEC958 optical RCA phono Inputs DI5 IEC958 coaxial L SDIF 2 input left A H SDIF 2 input right B Digital Outputs XLR Male DO1 AES3 output 1 Right Hand Side XLR Male DO2 AES3 output 2 XLR wiring conventions for both analogue and digital connections are pin 1 Screen pin 2 Balanced input or output Hot or pin 3 Balanced input or output Cold or Issue 1 0 Prism Media Products Limited 25 August 1998 Page 16 of 30 Prism Media Products Limited 2 Operation Manual 7 SPECIFICATION The following specification offered in good faith is subject to change without notice Errors and omissions excepted 7 1 Digital Inputs All inputs can handle sources with sampling rates from 32kHz to 96kHz Some inputs have special functions such as inputs 2 amp 3 Split96 or 2 wire mode and inputs 6 amp 7 AES3 ID or SDIF 2 7 1 1 General except SDIF 2 Jitter Tolerance Above 12kHz 0 5UI This is 88 6ns at fs 44 1kHz 50Hz to 12kHz Increases with falling jitter frequency e g 0 75Ul at 8kHz 30 UI at 200Hz Below 50Hz gt 128UI 22 7 us at fs 44 1kHz Note Jitter tolerance is a measure of the ability of a receiver to correctly decode a digital interface signal which has jitter Like most other jitter parameters it is normally measured in unit intervals A unit interval UI corresponds to the smallest nom
24. e if other inputs are selected for enabling ro disabling NOTE When XLR inputs DI2 and DI3 are configured for Split96 operation the digital XLR outputs DO1 and DO2 are automatically set to provide Split96 output if the DA 2 is operating at 88 2kHz or 96kHz Output channel status in this mode is in accordance with the proposed recommendations in ref 8 Press SET to leave Set Inputs mode and return to normal mode Issue 1 0 Prism Media Products Limited 25 August 1998 Page 10 of 30 Prism Media Products Limited Dream 2 2 Operation Manual 4 3 Set Level mode Set Level mode sets the maximum analogue output level for a full scale digital input Range is from 5dBu to 28dBu in either 1dB steps or fine steps of 0 05dB To enter Set Level mode the DA 2 must first be in INV El normal mode i e if the SET control is not already Inputs Level Master illuminated While holding the SET button down Spiit96 press the NV Level button Set Level mode is indicated when both NV Level and SET LEDs are lit In this mode the seven selector lights at the left hand side will show a pattern that relates to the output level The text in red under the LEDs indicates the value of each LED The maximum output level in dBu is calculated by adding the value of all the LEDs that are on Remember that when connecting to an unbalanced input as described in section 3 2 5 7 4 1 the output level will be attenuated
25. e taken to ensure that the digital source supplying the input signals is locked or synchronized to the DA 2 7 2 1 Clock slave synchronization The Dream DA 2 will normally be used synchronized with an external clock source In this slave configuration the internal clocks will be derived from the input signal or in the case of SDIF 2 from the WCK input The Dream DA 2 can operate as a slave if the incoming sample frequency is within one of the capture ranges of the high precision clock If the external clock is not within one of the high precision ranges then the DA 2 can also operate as a slave but without the same jitter attenuation performance over the 30kHz 50kHz and 60kHz 100kHz ranges High precision clock capture range 0 15 Nominal Minimum Range 32 kHz 31 96 to 32 04kHz 44 1 kHz 44 03 to 44 17kHz 48 kHz 47 93 to 48 07kHz 64kHz 54 40 to 73 60kHz 88 2 kHz 88 06 to 88 34kHz 96 kHz 95 86 to 96 14kHz Normal low rate clock capture range 40kHz 25 Non std 30 0 50 0kHz Normal high rate clock capture range 80kHz 425 Non std 60 0 100 0kHz Lock up time Signal present on output 0 1s High precision PLL locked 2 s Digital input to digital output timing difference 196 of sample period Note This is referred to the first transition of an AES3 or IEC958 frame or the rising edge of word clock Issue 1 0 Prism Media Products Limited 25 August 1998 Page 20 of 30 Prism Media Products Limited 122 Operation
26. his can be done by setting the output word length of the source device appropriately or by using a proprietary re dither or noise shaping device For example the Prism Sound SNS 4 Super Noise Shaper or the Prism Sound Dream AD 2 or AD 124 The latter are analogue to digital converters which can also operate as re ditherers or noise shapers when fed with a digital source 7 3 3 Balanced AES3 AES EBU professional format DO1 and DO2 These conform with the professional interface AES3 1992 with transformers for improved isolation Pin 1 of the XLR connector is connected to the chassis and the signal is output differentially across pins 2 and 3 Output impedance 110 S 20 Output level 4 V 10 terminated Rise fall time 20 ns 20 terminated A professional channel status pattern is generated for these outputs carrying the emphasis and word length information transcoded from the input and other appropriate information dependent on sample frequency or operating mode NOTE When the XLR inputs DI2 and DI3 are configured for Split96 operation the digital XLR outputs DO1 and DO2 are also automatically configured to provide Split96 output whenever the DA 2 is operating at 88 2kHz or 96kHz Output channel status in this mode is in accordance with the proposed recommendations in ref 8 Valid and user data bits are passed through from the selected digital input not present in SDIF 2 Reception errors are indicated by setting the val
27. ibilit Link pins 15 16 17 18 Sub Board PREV047 3 Option select not used Not fitted Issue 1 0 Prism Media Products Limited 25 August 1998 Page 28 of 30 Prism Media Products Limited Dream 2 4 2 Operation Manual 8 3 Mains transformer voltage selection The mains transformer has a tapped primary to allow operation at nominal voltages of 230V or 110V The brown lead is connected to the lower terminal on the mains inlet The upper terminal is connected as follows 110V Connect red primary lead to the upper terminal of mains inlet 230V Connect orange primary lead to the upper terminal of mains inlet The unused primary lead terminal should be firmly secured to the other primary leads If the mains operating voltage has been changed then the rear panel label should be changed to reflect this 9 ELECTROMAGNETIC COMPATIBILITY This equipment is intended for use in an electromagnetically controlled environment To maintain the performance specification it should not be subject to strong magnetic fields such as in the immediate vicinity of a power amplifier or cathode ray tube and all connections should be terminated as described below This is also required to ensure that emissions are within applicable norms and that it does not interfere with other equipment All coaxial connections should be made using a properly screened 75S cable with the screen connected to the outer of the connector at both ends All XLR connections shou
28. idity flag Issue 1 0 Prism Media Products Limited 25 August 1998 Page 22 of 30 Prism Media Products Limited Dream 2 4 2 Operation Manual 7 3 4 Optical consumer format This output is physically compatible with the Toshiba TosLink fibre optic connector If the selected input carries consumer format channel status and the unit is not set to clock master mode then that status is passed through Otherwise a consumer channel status pattern is generated carrying the emphasis information transcoded from the input Note In IEC958 there is no category code for DAC so with a non consumer status input the category code transmitted in the consumer channel status output is set to ADC Valid and user data bits are passed through from the selected digital input not present in SDIF 2 Reception errors are indicated by setting the validity flag 7 3 5 Coaxial consumer format IEC958 This conforms with the unbalanced interface defined in IEC958 clause 5 3 and carries consumer format channels status information as defined in IEC958 clause 4 4 2 This output is floating with the screen capacitatively coupled to the chassis Output impedance 75S 10 Output level 0 5V 10 terminated Rise fall time 22 ns 20 terminated The data carried on this output is identical to the data on the optical consumer format output See above 7 3 6 Coaxial SDIF 2 Sony format L and R These outputs conform with the interfaces initially used b
29. inal time interval in the interface signal for the AES3 or IEC958 interface formats there are 128 unit intervals per sample Therefore at a sample frequency of 44 1kHz the unit interval is 177 ns References 5 and 6 explain interface jitter in more detail Digital Input Resolution Word Length 24 bits The Dream DA resolves all the data bits of the digital interface formats Input signals are not truncated and hence truncation distortion does not occur For example a sine wave modulating only the lowest 4 bits of the 24 bit interface signal is reproduced at the correct amplitude Note that in conformance with the digital audio interface specifications all signals with consumer channel status and a Category Code indicating a 16 bit or 20 bit device and signals with professional channel status that indicate that the auxiliary audio data bits do not carry the main audio signal will have the lower 4 bits masked off to avoid non audio data adding to the audio The SDIF 2 format is also limited to a maximum resolution of 20 bits for the audio data 7 1 2 Balanced AES 3 XLR inputs DI1 DI2 DI3 Input impedance 110S These conform with the professional interface AES3 1992 Ref 1 with transformers for improved isolation However if the data is encoded according to the consumer format of IEC958 Ref 4 it is also decoded correctly Issue 1 0 Prism Media Products Limited 25 August 1998 Page 17 of 30 Prism Media Products Limited Dream
30. ing equipment will eliminate any common mode component on the output without introducing significant cable screen currents 7 4 1 Connecting the DA 2 to unbalanced inputs For optimum performance the DA 2 should be connected to an unbalanced input using only pins 1 and 2 Pin 2 should connect to the signal conductor and pin 1 should connect to the ground or return The signal level is then halved NOTE Use of output pin 3 instead of 2 will result in phase inversion It is possible to drive unbalanced inputs from pins 2 and 3 but this unbalances the output and can lead to hum In any case do not connect any of the three output pins to each other Differential output impedance 47S 1S pin 2 to pin 3 Single ended output impedance 24 S 15 pin 1 to 2 or 3 Coupling impedance to chassis 4 7 kS chassis to pin 1 2 or 3 Common mode range 70 V Issue 1 0 Prism Media Products Limited 25 August 1998 Page 24 of 30 Prism Media Products Limited Dream 2 4 2 Operation Manual 7 5 Performance Specification Specifications quoted in this section are to AES17 1991 ANSI S4 51 1991 Ref 3 at 48kHz with output level set to 22dBu for digital full scale input except where stated Frequency response Pass band fs 48kHz 5 Hz 20 kHz 0 05 dB 0 1Hz 21 7kHz 3dB fs 44 1kHz 5 Hz 20 kHz 4 0 05 dB 0 1Hz 20 8kHz 3dB fs 32kHz 5 Hz 14 5 kHz 0 05 dB 0 1Hz 15kHz 3dB fs 96kHz 5 Hz 35 kHz 0 05 dB 0 1Hz
31. ld use a screened twisted pair cable with the screen connected to pin 1 of the XLR connector at both ends In the case of the digital XLR connections this cable should be of 110S impedance Issue 1 0 Prism Media Products Limited 25 August 1998 Page 29 of 30 Prism Media Products Limited Operation Manual 10 1 2 3 4 5 6 7 8 REFERENCES AES3 1992 Recommended Practice for Digital Audio Engineering Serial Transmission Format for Two Channel Linearly Represented Digital Audio Data J Audio Eng Soc Vol 40 No 3 pp 147 165 June 1992 AES11 1991 AES Recommended Practice for Digital Audio Engineering Synchronization of Digital Audio Equipment in Studio Operations J Audio Eng Soc Vol 39 No 3 pp 155 162 March 1991 AES17 1991 AES Standard Method for Digital Audio Engineering Measurement of Digital Audio Equipment J Audio Eng Soc Vol 39 No 12 pp 961 975 December 1991 IEC958 Digital Audio Interface International Electrotechnical Commission 1989 Julian Dunn Barry McKibben Roger Taylor and Chris Travis Towards Common Specifications for Digital Audio Interface Jitter Preprint 3705 presented at the 95th AES Convention New York October 1993 Julian Dunn and lan Dennis The Diagnosis and Solution of Jitter Related Problems in Digital Audio Systems Preprint 3868 presented at the 96th AES Convention Amsterdam February 1994 AES 3id 1995 AES info
32. nto one of the following control modes Either Set Inputs Set Level or Set Master as described by the red front panel legends These modes allow the user to modify the configuration of the DA 2 In normal use they are not required 4 2 Set Inputs mode The Set Inputs mode is used to enable or disable the selection of individual digital inputs to avoid cycling through unused inputs when switching between sources Note in this mode the MUTE button has the function of enabling the inputs For that reason it is referred to as the MUTE Inputs control To enter Set Inputs mode the DA 2 must first be m El in normal mode i e if the SET control is not already illuminated While holding the SET button Mee om down press the MUTE Inputs button This mode is indicated by both the MUTE Inputs and the SET LEDs being lit The seven input indicators on the left of the unit illuminate to indicate the inputs that are enabled One or two of the indicators will be flickering to show the input s selected for enabling or disabling Press the MUTE Inputs control to toggle the enable state of this these input s The flickering will toggle between fast mostly on indicating enabled and slow mostly off indicating disabled DI Source Press the Select button to cycle through the other inputs so that they can then be BNC SDIF DI 7 AES3 OPT RCA Ss o DM DI2 DIS Did DI5 l amp DI eee ee e e enabled or
33. rmation document for digital audio engineering Transmission of AES3 formatted data by unbalanced coaxial cable J Audio Eng Soc Vol 43 No 10 pp 827 844 October 1995 Draft AES3 1992 Amendment 3 xxxx Serial Transmission Format for Two Channel Linearly Represented Digital Audio Data still in preparation July 1998 FURTHER INFORMATION Enquiries about this product should be addressed to Prism Media Products Limited William James House Cowley Road Cambridge CB4 4WX UK Phone 44 0 1223 424988 Fax 44 0 1223 425023 Email tech support prismsound com Web http www prismsound com Issue 1 0 Prism Media Products Limited 25 August 1998 Page 30 of 30 Prism Media Products Limited William James House Cowley Road Cambridge CB4 OWX UK E mail sales prismsound com Web www prismsound com Tel 44 0 1223 424988 Fax 44 0 1223 425023
34. t is possible to drive unbalanced inputs from pins 2 and 3 but this unbalances the output and can lead to hum In any case do not connect any of the three output pins to each other 3 2 6 Powering up for the first time Connect the mains supply and switch on the DA 2 unit The front panel LEDs should all illuminate momentarily if any of them fails to light it may be faulty If so then check again by turning the unit off and on If the problem is still evident contact your distributor After the unit has initialised one of the seven input selection lights on the left of the front panel will illuminate to indicate the selected input This indicator will be steadily on if the signal at the selected input is being decoded without error It will flash if a signal is not detected and briefly extinguish when individual errors are detected To select a different input press the round select push button on the left hand side of the front panel When you have selected the input you require then if the signal is decoded correctly and the unit is configured to the factory default settings then only the appropriate sample rate indicator and the input selection indicator will be steadily on This indicates that the unit is now operating correctly If the output level needs adjustment refer to section 4 3 NOTE If you are having problems with any of these controls it may be because the configuration has been altered from the factory defaults If you wish to
35. to correctly decode SDIF data independent of delays or phase 7 1 6 Coaxial word clock WCK input This input can be used to lock the DA 2 to a sample rate square wave or word clock It is used in conjunction with the SDIF 2 inputs to synchronize the Dream DA 2 internal clock to the SDIF 2 source equipment Input impedance 75S Input level 200mV to 10V pk pk Mark space ratio 40 60 to 60 40 Sync reference point Rising edge This input is ac coupled so that in addition to operation with the TTL levels typical of SDIF 2 word clock sources it will also work with lower signal levels such as from a double or triple terminated source with an optimum noise margin Note When using WCK synchronization the digital outputs of the Dream DA 2 are timed so that the start of the sample frame is coincident with the timing reference point the rising edge of WCK Specified delay measurements are also made from the timing reference point This input is not required if the Dream DA 2 is configured as clock master Issue 1 0 Prism Media Products Limited 25 August 1998 Page 19 of 30 Prism Media Products Limited Dream 2 4 2 Operation Manual 7 2 Synchronization The Dream DA 2 has two methods of synchronization In almost all applications the device will operate as a clock slave so that it derives its internal clocks from the incoming digital audio signal It can also be operated as a clock master see section 12 In that case care must b
36. urce of synchronization and defaulted to free run from the internal clock If externally synchronized at a non standard rate all indicators are off Issue 1 0 Prism Media Products Limited 25 August 1998 Page 13 of 30 Prism Media Products Limited Dream 2 2 Operation Manual 5 3 X2 indicator This LED will illuminate if the unit is synchronized to a rate between 60 and 100kHz When the X2 indicator is lit the D A converter sampling rate is double that of the normal lower rate indicator 5 4 Master indicator The Master indicator shows several different conditions LED off Sync OK external synchronization selected with no errors LED flashing in time with one of the frequency indicators No Sync external synchronization selected but failed LED on Clock master mode either no input or the input is correctly synchronized to the DA 2 master LED mostly on but occasionally blinking off Sample slipping in master mode each blink corresponds with a missed or repeated audio sample Issue 1 0 Prism Media Products Limited 25 August 1998 Page 14 of 30 Prism Media Products Limited Operation Manual 6 CONNECTORS 6 1 Analogue output connectors Conventional connections to a balanced analogue input should use a screened twisted pair lead The DA 2 output pins 2 and 3 should be wired to the two conductors of the pair and pin 1 to the cable screen The other end of the cable should be connected in a similar manner with
37. y the Sony PCM 1610 1630 PCM encoder and often called SDIF 2 Signals in this format are at TTL levels and transmitted most significant bit MSB first in non return to zero NRZ format A synchronization pattern identifies the start of a new sample word Output impedance approximately 30 S Load impedance 755 Output level 2 8 V 0 5 V when terminated in 75 S Rise fall time 60 ns The embedded flags carried on the SDIF 2 outputs are set as follows C Emphasis Set if CD 15 50us emphasis is indicated on the selected input C Dub prohibit Always clear 7 3 7 Coaxial SDIF 2 Sony word clock format Issue 1 0 Prism Media Products Limited 25 August 1998 Page 23 of 30 Prism Media Products Limited Dream 2 4 2 Operation Manual This output carries a TTL level square wave at the sample rate The rising edge coincides with the start of a sample frame on the digital outputs Electrically it is identical to the SDIF 2 L and R outputs This output is normally used to synchronize equipment that is using the SDIF 2 data outputs but may also be used to synchronize any equipment which will accept a Wordclock ref sync 7 4 Analogue Outputs The analogue outputs are on a three pin XLR connector with positive and negative signal polarities on pins 2 and 3 respectively and the mid point on pin 1 These pins float together with respect to the chassis earth This high common mode impedance means that the pin 1 screen connection to follow
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