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AD147

1. 10dB 100Hz MF 15dB 2k8Hz HF 10dB 10kHz 15dB MAX 30Hz VARIABLE TURNOVER Q 1 2 PEAK amp DIP RECIPROCAL 15dB MAX 30kHz VARIABLE SLOPE 3dB 110Hz 12dB OCTAVE REFER TO CURVE lt 0 03 1kHz 0dBm OUTPUT lt 0 15 40Hz to 20kHz 15dBm OUTPUT ILLUMINATES AT 15dB AT THE PRE FADER POINT lt 70dB 40Hz to 15kHz INTERCHANNEL amp INTERGROUP MIC lt 126dB EIN 20Hz to 20kHz 200R SOURCE WITH RESPECT TO THE INPUT LINE 70dB SNR 20Hz to 20kHz THRESHOLD 8dB RATIO 7 1 ATTACK 2 SETTINGS INTERNALLY SWITCHABLE 1 4ms 2 0 8ms RELEASE 2 SETTINGS INTERNALLY SWITCHABLE 1 250ms 2 80ms POSITION 1 IS SET AT FACTORY MECHANICAL SIZE 6 I P 8 I P 10 I P 12 VP A 350 411 482 533 B 325 386 447 508 ALL DIMENSIONS IN MILLIMETRES WEIGHT ei P 8VP 10V P 12VP 7 4 8 7 10 0 11 3 ALL WEIGHTS IN KILOGRAMS EQUALISATION CURVES AD 147 HIGH AND LOW EQ 10 100 1000 10000 100000 Frequency AD 147 MID AND HPF EQ dB 0 10 100 1000 10000 100000 Frequency 10 This page is blank CONNECTOR PANEL 12 All input and output impedances and levels are to be found in the TECHNICAL SPECIFICATION All inputs to and ou
2. FLEX EQ our industrial strength equaliser and wish to be able to use it when making original recordings Being latter day converts we have included circuitry to take full advantage of all M S techniques even shuffling in both production and post production AD149 is Audio Developments tribute to and celebration of the genius of Alan Blumlein We appeal to all AD149 users to break with tradition and just on this occasion study the manual to reveal all the mixer s secrets THIS IS ESSENTIAL Well we HAD every intention that AD149 would complete the 140 series We d reckoned however without the persistence nay insistence of our customers for a mains operated version of the AD146 with four auxiliaries we ve called it AD144 INTRODUCTION Unpacking If there are any signs of damage to the outside of the carton please notify us or your supplier immediately regardless of the unit s apparent physical condition This is in case a claim has to be made at a later date because of previously undetected transit damage The packaging material should not be discarded until the mixer has been acceptance tested and a suitable transit storage case is available for secure safe storage Visual Inspection Identification please make a separate note of the serial number for your own capital equipment records Ensure that it agrees with the number on the invoice packing note The serial number label is on the back cover adjacent
3. I AUX OPs MIX L M o M 5 M o 24 l S Zd L 3 L o R i x si R i S 14990601 1a 2a 3a a recording made in the M S domain is ready for the application of all possible post production techniques This diagram also illustrates the manner in which it is possible to create an auxiliary output in the opposite domain from the main L R output 34 POWER SUPPLY UNIT TYPE AD100 09 The AD100 09 mains POWER SUPPLY UNIT is suitable for driving most of AUDIO DEVELOPMENTS range of portable audio mixers This PSU is a single rail device providing 500mA of current at 14v DC potential and is used as a substitute for battery power with mixers containing an internal DC DC converter The AD100 09 may be powered from either a 110 120v AC source or a 220v 240v AC source Ensure that the AC Voltage Selector Switch on the front panel is in the correct position for the source in use Operating the equipment at the wrong voltage could be hazardous Care must be taken to connect the LIVE NEUTRAL and EARTH pins of the PSU s IEC mains connector to the corresponding terminals associated with the AC source The ON OFF switch contains an indicator that illuminates when the PSU is operational FOR SAFETY REASONS AD100 09 POWER SUPPLY UNIT MUST BE CONNECTED TO MAINS EARTH Any maintenance to the PSU or its mains cable assembly should be per
4. M S microphone is set up with incorrect orientation of the S microphone changing the phase of the S microphone channel will rectify the situation without having to disturb the microphone Mixing in the M S domain is a legitimate technique any X Y microphone will first have to be matrixed to the M S domain and simultaneous mixing in the M S and L R domains is possible with AD147 Conversion facilities may be introduced into signal paths where they are most effective the switches labelled MTX 6 and 17 on the output module introduce a matrix amplifier into the main mixer output and across the auxiliary outputs The flexibility and capabilities of the monitor module are also increased by an order of magnitude with the inclusion of a matrix amplifier Eg for any L R stereo signal appearing on the monitor module MTX 10 will reveal mono compatibility M on monitor 1 left and out of phase components S on monitor 1 right Both of these signals may be isolated using the monitor BAL control 17 perhaps in conjunction with the MONO switch 11 Again restricting the range of the balance control compromises these facilities in that the M amp S signals cannot be individually isolated Blumlein s microphone techniques have advantages over all others X Y and A B such that it is worthwhile using M S microphones even when mixing is to be done in the L R domain For example the M microphone will be placed in the optimum position for a mono im
5. Then select the limiter function and adjust VR1 until the output signal starts to fall typically 0 2dB The DC voltage at PIN 12 of IC 1 should be approximately 2 0v After setting VR1 adjust the output signal to just greater than 8dBu with the limiter deselected Introduce the limiter and adjust VR2 until the output signal falls to 8dBu This is the THRESHOLD setting If a different threshold setting is required alter the signal levels accordingly The DC voltage at PIN 10 of IC 1 should be approximately 0 6v different from that at PIN 12 23 The right output can be set using the above procedure but the preset and IC numbers change to correspond with the output being calibrated 24 The link function has no individual setting of its own To ensure this works within specification it is important that L and R outputs are set up as a pair After following the above procedure the DC voltages at PINS 10 and PINS 12 of the ICs should be identical Tolerance 0 05v with typical figures at PIN 10 of 2 6v and PIN 12 of 2 0v There are two DIL switches associated with the attack and release times one for the left output the other for the right The diagram below illustrates the two settings for each function ie a fast and slow time for both attack and release The factory setting is the SLOW position in both cases NOTE WHEN DIL SW IN ON POSITION SET 0 AS ATT AND REL IN FAST MODE 6 For correct tracking of the
6. best in the best of possible worlds Voltaire Pre Fader Listen When designing AD146 space was always at a premium but almost non existent when we had to do piffle sic and monitoring Compromise was in the air but a compromise which became one of the most elegant features of the AD146 This compromise is now included in AD147 Very simply the monitor 1 output whether stereo or mono is fed to the headphones ie monitor 2 amplifier which also has its own level control 18 via the headphones logic Once the correct level has been set for monitor 1 output the level of this signal to the headphones can be further adjusted by the monitor 2 level control 18 The talkback return signal is fed to the PFL mix busses which also have their own ganged potentiometer 19 to control the level to the headphones When PEL is engaged on a channel or if the talkback return is in use logic changes the source of monitor 2 from monitor 1 to the PFL mix busses The internal microphone 20 can be routed TB 12 to the 6 pin XLR connector mixed into the L R output 13 and mixed into auxiliary 1 amp 2 outputs 14 Microphone level is set by potentiometer 15 prevent feedback when the microphone is routed to the main and auxiliary outputs monitor 1 output is 29 automatically dimmed by 20dB When TB 12 is selected the microphone signal replaces any other signal present on TB SEND M S NOTES The M S techniques propo
7. in its portable guise We wish you many trouble free hours of use from your mixer As a company we are fully committed to BS EN ISO 9001 Should you have any problems or require any further information on FLEX EQ or the M S microphone technique please do not hesitate to contact us on 01543 375351 or by fax on 01543 361051 WARNING IMPORTANT SAFETY INSTRUCTIONS The user of electrical products must be familiar with their potential dangers and fundamental precautions must always be taken Please read the following text carefully Power supply units manufactured by Audio Developments Ltd are not user serviceable There are no user serviceable parts associated with any such power Supply unit THE OUTER COVERS MUST NOT BE REMOVED Such a power supply unit is solely for use with audio mixers and sound processors hereafter called the equipment manufactured by Audio Developments Ltd Always use a cord set accepted by a National Approved Body EARTHING GROUNDING When using an external power supply unit that is connected to the mains supply to drive the mixer it must be CONNECTED TO EARTH In certain types of malfunction or breakdown earthing provides a path of least resistance for electric current and considerably reduces the risk of electric shock DANGER Incorrect connection of the equipment grounding earthing conductor can result in the risk of electric shock Where possible obtain a pre wired mains lead from a reputable supplie
8. will be centred and the S switch selected on the S channel to create a matrix across the M and S channels With CH 1 selected on the monitor module MON on the M channels will now audition an M microphone on monitor 1 L amp R and headphones L amp R outputs When setting up M S microphones the S channels may be monitored in the same manner BEFORE the S switch is selected After selecting the S switch on the S channels only the complete M S stereo microphones may be monitored automatically in L R stereo The potential of these microphones may be checked by changing the M S relationship ie by varying the input gain of the S channels Spot microphones will be panned to their correct position in the final L R image Monitor BAL 17 can be used on L R STEREO 4 to steer the stereo signal to confirm matching with a visual image Earlier we mentioned conflicting monitor requirements a problem arises when monitoring an S channel after its S switch has been selected In this case S would appear on the left and S on the right not very useful To overcome this difficulty swing the monitor BAL control 17 hard left and select MONO 11 thus isolating the in phase signal from the S channel Alternatively and particularly if the engineer has requested a restricted swing on the BAL control 17 selecting MTX 10 and MONO 11 will achieve the same result When mixing in the M S domain and using M S microphones M channels will b
9. CONTENTS SCENARIO INTRODUCTION UNPACKING VISUAL INSPECTION SPECIFIC POINTS IMPORTANT SAFETY INSTRUCTIONS POWERING TECHNICAL SPECIFICATION EQUALISATION CURVES CONNECTOR PANEL CONNECTIONS MODULE LAYOUT AND FUNCTIONS MIC LINE INPUT MODULE OUTPUT MODULE ADJUSTMENTS AND CALIBRATIONS MONITOR MODULE M S NOTES AD100 09 POWER SUPPLY UNIT CUSTOMER NOTES AND FACTORY MODIFICATIONS TECHNICAL LIBRARY Co Co CO 34 35 SCENARIO Time was when it became necessary to update the ubiquitous AD145 PICO mixer Our survey showed two main requirements as well as Audio Developments build and audio qualities narrower and shorter modules were required and the simple but effective equaliser from PICO had to be retained By this time 4 track recording equipment had begun to trickle into the marketplace Nagra D etc so we decided to give the new mixer four outputs Because of the lower noise floor of modern digital recorders the level of input signals may be reduced We have taken advantage of this fact and lowered the slope ratio of the limiters to 7 1 By so doing not only is signal distortion greatly reduced but also the artefacts associated with limiters become much less noticeable or objectionable Also sixty years after the event sound engineers have come to realise the potential of Blumlein s M S techniques to this end facilities have been incorporated to take advantage of these techniques The result is A
10. D146 a four output mixer This was followed by AD148 edit mixer Based on AD146 two comprehensive left and right monitor modules have been added for editing purposes lf a mic line module is included for commentary or voice over purposes its input gain switch can be changed to a potentiometer and its gain structure changed to ensure consistent level matching with a fixed mechanical point of reference Unfortunately this way of working does reduce headroom and also compromises a mixer s noise performance After AD146 AD148 it was back to the drawing board Our customers were still demanding a two output mixer as a true replacement for the PICO and with the PICO s simplicity Despite past assurances to the contrary T powering is still required And could we incorporate auxiliaries And could we possibly bring it to market at entry level We have and we have and that s MERCURY AD147 AD149 completes the 140 series of mixers and has a repertoire of party tricks not to be found in any other mixer not even for ready money The design team took as its starting point our list of all the ideas and suggestions presented to us over the past few years Many of these requests came from film sound recordists a sub set of recordists we have unintentionally neglected in the past Since the days of R amp D for AD146 channel insert points suddenly became de rigueur transpires that many sound engineers have experienced the power of
11. age whereas mixing to mono the signals from an X Y stereo pair introduces phase anomalies When using M S microphones we suggest for convenience that M microphones are inserted in odd numbered channels and the corresponding S microphones are inserted in the next channels above Any M S microphone will be in the M S domain at the pre and post fader auxiliary points M signals may be mixed on AUX1 and S signals on AUX2 then matrixed to L R on the auxiliary outputs Alternatively a L R signal may be recorded from the main output and an M S signal from the auxiliary outputs Spot microphones would be added only to the AUX 1 mix Many are the tricks one can perform in the M S domain but the only one considered here is the possibility of changing the width of a L R stereo signal Should readers wish to investigate further M S techniques they are invited to request a copy of the M S Handbook written for our PORT A FLEX units AD066 11 M S stereo microphone amplifier and AD066 12 M S post production matrix amplifier The L R domain and M S domain can be combined to produce eight possible mixing paths Of these eight the following three are the most commonly used A mixture of X Y and M S inputs may be mixed either in the L R domain or the M S domain When all inputs are in X Y form mixing will normally be done in the L R domain 31 When mixing in the L R domain and using one or more M S stereo microphones the panpots on M and S channels
12. ash when the internal batteries become dangerously low Discharged to 10v Meter illumination 9 should not be used indiscriminately Overuse will cause internal batteries to discharge much quicker Switches 10 11 12 are interlocked and select the signal to be metered With no switches selected the main left and right outputs appear on meters 1 and 2 respectively Switch 10 selects auxiliary 1 and 2 to the meters Switch 11 routes monitor 1 left and right signals to the two meters and overrides switch 10 Switch 12 routes PFL to both meters and overrides switches 10 and 11 Matrix selector 6 see later in M S NOTES Switch 13 selects the frequency of continuous line up tone 1kHz or 10kHz to L R output when 15 is selected and to auxiliary outputs when 16 is selected In both cases the line up tone replaces any signal which may be present on the outputs If interrupted 14 is selected continuous tone replaces the signal on the right outputs and three second bursts of tone replace the signal on the left outputs If desired interrupted tone can be directed to the right outputs by following the instructions on page 24 Matrix selector 17 see later in M S NOTES Auxiliary output levels are controlled by potentiometers 20 and 21 The faders 18 19 control the level of the main left and right outputs The calibration point of the various output level controls is where they are fully open The limiter
13. e panned left S channels will be panned right and spot microphones will be panned left to mix with the M channels only MON on an M channel will audition the M signal on monitor 1 left output and MON on an S channel will audition the S signal on monitor 1 right output By selecting MONO 11 on the monitor module each of these signals will appear on monitor 1 left and right outputs If the M and S channels are selected simultaneously to MON the resultant M S signal is incomprehensible but can be converted to the L R domain by selecting MTX 10 on the monitor module By using the monitor BAL control 17 this L R signal can have its width changed and potential realised without changing channel settings A main output in the M S domain may be monitored in like manner and the M S relationship changed using the monitor BAL control 17 without affecting the main output An M S main mix may be matrixed to the L R domain for the final output from the mixer by MTX 6 on the output module Signals for output monitoring are taken from the final mixer outputs ie after the faders and output matrix amplifiers Monitor module controls are in the following order GAIN BALANCE MTX 32 Monitor 1 left and right outputs may be mixed to mono by selecting MONO 11 an LED indicates when this function is in use The mono signal is fed to both sides of monitor 1 output When the monitor 1 path is not otherwise in use the monitor module can p
14. formed by a qualified engineer CHARGING If nickel cadmium cells are fitted in an AD140 series mixer they may be recharged in situ from AD100 09 power supply whether the mixer is in use or not Maximum current is set at 250mA in addition to the 500mA of current supplying the audio electronics The charging circuit has its own ON OFF slide switch and LED indicator DO NOT ACTIVATE THE CHARGE CIRCUIT UNLESS THE MIXER IS FITTED WITH NICKEL CADMIUM CELLS FUSES Two 20mm ANTI SURGE fuses protect AD100 09 against fault conditions Should either fail it is strongly recommended that the cause be traced Refer to the TECHNICAL LIBRARY Only suitably qualified personnel should service the power supply unit The fuse holder on the front panel contains the mains fuse 250mA HRC TYPE T 240v AC For continued safety the specified fuse link must be fitted in the mains fuse holder when a replacement is required Ensure it is of a type approved by a National Approved Bogy DC OUTPUT XLR PIN 1 Ov PIN 3 NOT CONNECTED PIN 2 CHARGE PIN 4 14vDC DO NOT REMOVE THE OUTER COVERS NOTE The power supply unit should be serviced by a suitably qualified engineer Only genuine spare parts with identical specifications must be used It is dangerous to change the specification or modify the product any way 35 CUSTOMER NOTES AND FACTORY MODIFICATIONS 36
15. gnal sit in the mix By alternating CH 1 and L R STEREO 4 and routeing the appropriate microphone channel to MON the question is easily answered This is a non destructive SOLO IN PLACE SIP use of the monitor 1 path 28 Alternatively a mix separate from the main L R mix may be set up on the monitor 1 path using CH 1 only and independent of the channel L R routeing This could also be a mix minus The identical contribution of any channel to both the mix minus or monitor mix and L R output will be controlled by the channel fader The output from the monitor 1 path and to monitor 2 output is controlled by a ganged potentiometer 16 The matrix selector 10 with its ON LED and monitor 1 balance control 17 are both dealt with in the M S NOTES When the balance control is fully anti clockwise L only the LH signal appears on monitor 1 amp 2 outputs Similarly when fully clockwise R only the RH signal appears on monitor 1 amp 2 outputs Selecting MONO 11 will place these LH amp RH signals on both sides of the monitor 1 amp 2 outputs If a restricted range 10dB has been selected for the balance control these facilities will be compromised A maximum difference of only 20dB would be achievable between the L amp R signal levels Operating on monitor 1 output is the dim control 9 which dims the output by 20dB Dim does not affect a monitor 1 signal that is routed to the headphones All is for the
16. is procedure to obtain an accurate reading at each of these three points Now check the calibration of all meter points 22 SDR Scale with a main output signal level of 6dBu adjust VR1 to obtain a reading of 12 Increase the output signal to 6dBu and use VR2 to obtain a reading of 0 on the meter Lower the output signal to 18dBu and adjust VR3 to give a reading of 24 Repeat the procedure to obtain an accurate reading at each of these three points Now check all points on the scale for calibration Main output limiters calibration involves two presets per output to be found on the output module LH PCB Using the L output as the example Biasing and threshold are adjusted as follows VR1 biases the limiter circuit to the point of correct operation and VR2 sets the threshold Labelled SET 0 and THR respectively on the left hand PCB Determine whether the left hand PCB is issue 3 or below or issue 4 and above If issue 4 read PIN 5 of IC1 instead of PIN 12 of IC1 in the following paragraphs Issue 4 does not indicate an early improvement in circuitry simply a change in layout to make testing simpler With no signal present VR1 should be adjusted to give a reading in the range 1 5v to 2 5v at PIN 12 of IC 1 VR2 should be adjusted to give a reading in the range 2 5v to 3 5v at PIN 10 of IC 1 Apply a signal at 1kHz to the mixer to give a level of 0dBu at L output
17. iser section The high frequency control 19 has an amplitude of 10dB at 10kHz with variable slope The mid frequency control 20 has an amplitude of 15dB at 2k8Hz with a proportional Q of 1 2 The low frequency control 21 has an amplitude of 10dB at 100Hz with variable turnover Despite modules being narrower and shorter than those of the PICO we have been able to incorporate an auxiliary section The two auxiliaries are independent of each other each has its own on off switch 7 and 9 pre post fader selector 8 and 10 and level control 22 and 23 The level controls act purely as attenuators when set at 10 and sourced post fader the auxiliary outputs track with and are at the same level as the L R outputs from the module The auxiliary on off switches are independent of the channel on off switches even when the channel L R routeing is switched off pre and post fader auxiliary outputs are still available For additional flexibility separate switches control the left 12 and the right 13 outputs from the module the panoramic potentiometer 24 routes the signal proportionately to the left and right mix busses The monitor 1 path is the true output from the module independent of any other routeing and is derived from the output of the panpot and S switch 11 if selected 17 In conjunction with CH 1 and MONO 11 on the monitor module MON 14 can be used for AFL after fader listen monitoring or SIP s
18. ition X Y M Sin isolation Similarly facilities must be provided to monitor main and auxiliary outputs whether they are in the M S or L R domain Itis a bonus to be able to determine the potential of these various signals in their after life ie in post production The signal s to be auditioned on the left and right unbalanced outputs of monitor 1 and monitor 2 is are selected from the bank of switches 1 to 8 These switches are not interlocked in order that any desired mix of signals may be achieved Switch 2 selects the main left output from the mixer to monitor 1 amp 2 left and right outputs Switch 3 selects the main right output from the mixer to monitor 1 amp 2 left and right outputs Switch 4 selects the L R STEREO output from the mixer to monitor 1 amp 2 Switch 5 routes the stereo return to monitor 1 amp 2 The return will probably be the signal from the playback head of the tape recorder By alternating adjacent switches 4 and 5 A B comparisons to and from tape may be made Switches 6 7 8 provide the same functions for the auxiliaries as switches 2 3 4 do for the main L R output CH 1 operates in conjunction with the MON switch on the channels This MON signal is the same as that which drives the left and right mix busses If MONO 11 is also selected the monitored signal becomes a true mono AFL after fader listen signal from the channel How does a microphone si
19. limiters FAST Z when linked ri together the DIL switch settings RH DUTPUT should identical 25 The diagram below illustrates the procedure for placing interrupted line up tone on the RH output and AUX 2 Lo MARKER TONE TO CHANGE IDENT TONE TO RIGHT OUTPUT P Es S Remove through pin 510 gt lt N SR R45 e COMPONENT SIDE VIEW Remove through pin from Y2 as indicated Cut track between X2 and Y1 Add link between X1 and X2 Add link between Y1 and Y2 NOTE Only make connection to component side pad of Y2 RKUN 14991101 26 MONITOR MODULE 27 This section should be read in conjunction with M S NOTES We at Audio Developments believe a monitor section that tells less than the whole truth is nothing worth Our designers therefore devote as much care to the monitor paths as they do to the main signal paths With two minor changes the monitor module is identical with the AD146 monitor module which has been tried and tested in the field and studios It is necessary to be able to audition in left right stereo ie a form the human brain understands an X Y A B stereo microphone and an M S stereo microphone whether the channel panpots are set centrally or hard left and hard right thus creating conflicting monitor requirements It is also necessary to be able to aud
20. nd crosstalk Powering 48v phantom or 12v tonader may be selected before or after the microphone is connected to the module Module fix screws Hexagon head screws are used to fix the modules and back cover The size being 1 5mm HEX A F with a 2 5M thread If it becomes necessary to remove modules or back cover it is strongly advised using a good quality hexagonal head driver Use of a screwdriver however desperate is not recommended Surfaces every working surface is covered by a hard plastic membrane which is printed on the reverse side These surfaces may be cleaned by most solvents and without fear of the legends being erased Connectors for convenience the connector panel is labelled for reading from above All connectors are in line with their corresponding module Every input module is mechanically shielded against radio frequency interference Abbreviations PPM peak programme meter VU volume unit VR variable resistor X Y coincident stereo microphone A B spaced apart stereo microphone M S middle side techniques and microphone described by A D Blumlein PCB printed circuit board HPF high pass filter Finally may we draw your attention to our range of portable battery operated audio toys called PORT A FLEX AD066 which will complement your new mixer No 1 broadcast quality compressor limiter Nos 3 7 8 10 distribution amplifiers for microphone and line level signals No 13 the aforementioned FLEX EQ
21. noise high gain amplifier designed for AD146 An input pad or attenuator is rendered unnecessary because the available 40dB gain change is achieved with a single potentiometer acting on the feedback alone This has the advantage of not degrading signal to noise performance as the gain is lowered The reverse log law potentiometer ensures low sensitivity high resolution control without all the gain occurring in a small angular deviation A DC voltage is available for 48v phantom powering 1 and 12v tonader powering 2 of condenser microphones These two switches are interlocked with tonader power taking precedence over phantom power The line input is isolated from the microphone power and no damage can be done to external equipment if either or both of the power switches remain selected Such is the isolation between signal paths a microphone input Conn 1 and a line input Conn 2 may simultaneously be connected to a channel With line selected 3 the input gain control at MIN and the fader set at 0dB the mixer has unity gain with 10dB gain in reserve All output faders must be set at OdB Phase change 4 follows the mic line selector and is therefore active on both inputs The high pass filter 5 follows the input amplifier and is as above active on both inputs The filter has a 12dB per octave slope and is 3dB at 110Hz This filter is independent of the equaliser The EQ selector switch 6 routes the signal through the equal
22. olo in place monitoring procedures which are fully described in the monitor module section When monitor 1 is not in use for monitoring per se it may be set up to create another mix or perhaps a mix minus Monitor 1 output automatically appears on monitor 2 headphones output PFL 15 routes the signal at the fader input to monitor 2 ie the headphones output jack LED 16 indicates when PFL has been selected PFL takes precedence over any other signals that might be present on the headphones output monitor 2 The overload LED 17 illuminates 3dB before clipping at the input to the channel fader The fader is calibrated 10dB down from its fully open position allowing the operator to work with 10dB of gain in reserve Faders on adjacent modules can be coupled for stereo operation by the use of standard ganging clips S matrix selector 11 creates a matrix amplifier across an adjacent pair of input modules See also monitor and M S sections 18 This page is blank OUTPUT MODULE 20 The meters are to broadcast specification with switchable functions PPM and VU movements are available to choice The upper meter 1 reads battery status BATT 8 left and auxiliary 1 output levels monitor 1 left output level and PFL The lower meter 2 reads right and auxiliary 2 output levels monitor 1 right output level and PFL The monitor 1 signal will be the one or mix selected on the monitor module The mixer ON LED 7 will fl
23. r with the correctly fitted mains connector for the type of mains outlet in use otherwise one correctly wired and checked by a qualified electrical engineer lf your mains lead is not suitable for the mains outlet have the correct plug fitted by qualified personnel The MAINS PLUG of this equipment is the primary disconnect device Therefore in the final application ensure it remains close to the equipment and easily accessible POWERING The mixer may be powered from either internal cells or an external DC power source The integral battery compartment requires a total of 10 size C cells Access is gained via a captive lid which is retained by two 90 degree turn buckles The lid hinges outwards 45 degrees from the back panel When installing new cells the row nearest the hinge should be fitted first Either conventional dry or rechargeable nickel cadmium cells may be used NICADs may be recharged in situ through the 4 pin POWER IN connector The circuit for recharging is already incorporated within the mixer A voltage in the range 15v to 24v DC 250MA is required on PIN 2 of the POWER IN XLR When driving the mixer from an external power source PIN 1 is the Ov connection and a voltage in the range 12v to 15v DC should be supplied to PIN 4 The power source should be capable of delivering approximately 400mA allowing some capacity for phantom powering If an external power supply unit PSU is to drive the mixer and simultaneo
24. roduce a mono mix of the main left and right outputs or a mono mix of the AUX1 and AUX2 outputs by selecting MONO 11 and 4 or 8 as appropriate If required it can also produce a composite mix of the main and auxiliary outputs a mix that follows the output level controls When mixing in the L R domain without M S microphones X Y A B microphones will be panned hard left X and hard right Y and any spot microphone will be panned to its correct position in the final L R image CH 1 on the monitor module and MON selected on both channels of an X Y pair auditions each stereo microphone which prior to recording can be checked for steerability using the monitor BAL control 17 on a spot microphone is solo in place usage of the monitor system On page 29 a way was suggested for changing the width of the image from an X Y microphone Unfortunately this is not possible with AD147 nor in the author s experience with any other mixer However what is possible with AD147 is the capability of checking the effect of changing the spacing of an X Y microphone without actually doing so at the set up stage Route the X signal to auxiliary 1 and the Y signal to auxiliary 2 and introduce the matrix across the auxiliary outputs Monitoring AUX STEREO 8 plus MATRIX 10 BAL 17 will reveal the effect of angular changes which may be made upon the X Y microphone 33 OUTPUT LIMITER METER amp MONITOR OUTPUT FADER
25. s on the main left and right outputs are switched into circuit as a pair 4 and may be linked for stereo operation 5 The limiter LEDs 3 indicate when limiting is taking place On the left hand PCB of the output module are two DIL switches one for each limiter These switches affect the attack and release times of the two limiters fast or slow When linked the limiters should have the same settings for attack and release Threshold and ratio are set at the factory Technical details of the limiters are to be found in the SPECIFICATION 21 ADJUSTMENTS AND CALIBRATIONS Refer to component location diagrams in TECHNICAL LIBRARY Line up tone oscillator the preset VR4 that adjusts its level at the outputs of the mixer is mounted on the right hand PCB of the output module and can be adjusted from the copper foil side of the board Low battery indicator the preset VR3 associated with this facility is mounted on the right hand PCB of the output module The low reading is set at the factory and corresponds to a set of batteries having discharged to 10v Ona VU meter low volts is at OVU On a PPM meter it is indicated by a separate marking yellow on a BBC scale and red on an N10 and SDR scale Meters either a VU or a PPM may be selected A choice of 3 scales is available for the PPM BBC N10 SDR VU meter there is one preset on the VU meter PCB for meter adjustment Set an input module for a line input and introduce a 1kHz
26. sed by Alan Blumlein in the early nineteen thirties have recently been re discovered These techniques fall into two parts those used during original recordings and those used in post production The way to change the width of the image from an X Y stereo microphone without physically moving it or from an existing L R recording is to convert to the M S domain in order that the M S relationship can be altered Because the human brain is incapable of unscrambling signals in the M S domain all M S signals must be returned to the L R domain These conversion procedures can be achieved electronically or by the use of a specially designed transformer and are called encoding or is it decoding In order to overcome any possible ambiguity we refer to the encoding and decoding processes as matrixing since they involve a matrix amplifier This matrix amplifier will accept a L R input and convert it to an M S output or an M S input and convert it to a L R output hence the confusion The matrix is a sum and difference amplifier which adds in phase the two input signals to produce a left signal M S L it also adds the two input signals in anti phase to produce a right signal M S R Similarly L R M and L R S MATRIX AMP Increasing the S signal widens the L R stereo image decreasing the S signal makes the stereo image narrower 30 Changing the phase of an S signal swaps over the left and right outputs of the matrix Thus if an
27. t Pin 5 Ret Balanced return at line level Pin 6 Control The talkback send output has a low output impedance with a capability of driving headphones of 25 ohms impedance or greater The internal talkback microphone is routed to the talkback send when the TALKBACK switch is selected otherwise a mono mix of Monitor 1 is fed to this output This function is set at the factory but may be disabled by the DIL switch on the left hand printed circuit board of the monitor module The return signal from an external source feeds onto the PFL line This is initiated by grounding the control line PIN 6 at the external source Thus for example a two way conversation can take place between mixer and boom operator with the boom operator being able to listen to programme when no communication is taking place A three position rocker switch BATT EXT 10 selects either internal batteries or an external DC power source Power to the mixer is confirmed by the MIX ON LED on the output module This LED flashes when the supply voltage falls below the safe operating level of 10v External powering of the mixer is via a 4 pin XLR 11 XLR Pint Ov Pin2 Charge Pin3 NC Pin4 12 15v DC A suitable external power supply is Audio Developments AD100 09 but any external DC source must be capable of delivering 750mA at 12v 14 This page is blank MIC LINE MODULE 16 The discreet microphone amplifier is a transformerless version of the ultra low
28. ternal Battery DC Supply Supply Until the mixer has been acceptance tested we strongly recommend that modules are not removed for adjustment If adjustments are necessary refer to the section on adjustments and calibration All customer functions are external except the following Limiter threshold is set at the factory at 8dBu PPM 6 but an internal preset potentiometer allows adjustment to any other level above 0dBu The limiters are to be found on the left hand PCB of the output module Reverse talkback output is set at the factory to provide a mono mix of monitor 1 left and right outputs rather than mute when the main talkback switch is released This function can be disabled by the DIL switch to be found on the left hand PCB of the monitor module Line up tone at 1kHz and 10kHz is calibrated on the meters to PPMA giving a line output level of 0dBu with L R and AUX 1 2 controls set to maximum NOTE PPM4 refers to the mark on a BBC PPM Scale Other meter scales have a different mark at OdBu level Alternative calibration levels are possible via the internal preset LH output ident as an alternative to continuous tone on both left and right outputs and AUX 1 2 outputs the LH and AUX 1 outputs can be pulsed with tone for three seconds Microphone powering the mixer will remain unconditionally stable if the powering on unterminated input channels is switched off this also improves the noise performance a
29. to the battery compartment Configuration check that the correct number and combination of input modules have been installed If for any reason you wish to change the positions of the modules do not do so until after completion of any acceptance tests Any tests then made will be to a known configuration and can be compared with our factory records Temperature check the meter glasses for condensation If the package has been in transit during cold weather leave the mixer for at least 12 hours to allow it to return to normal room temperature Any measurements or subjective tests then made will be to a known temperature reference Specific Points Battery compartment the mixer has an integral battery compartment to accept 10 size C cells and is formed as part of the bottom transversal extrusion This helps to lower the centre of gravity as well as adding to the rigidity of the frame DC DC converter is mounted on the top side of the battery housing and is underneath the fader section of the output and last four input modules In order to facilitate the testing and calibration of all modules a set of two extender modules is available from the factory Fuses to protect the mixer and internal power supply are mounted on the power supply converter board Access is gained by removing the output module 20mm 1A ANTI SURGE HRC fuses are used one for the internal battery power supply and one for the external DC supply FUSES Ex
30. tone from an audio signal generator Adjust levels to achieve a reading of 4dBu at a main output on an AC millivoltmeter measured across pins 2 amp on the output XLR Switch the appropriate meter to the selected output and adjust the preset to give a reading of OVU PPM the driver PCB has three calibration controls presets VR1 adjusts the reference level VR2 and VR3 adjust the law of the meter VR2 adjusts the upper sector of the scale and VR3 adjusts the lower sector To initiate calibration set each preset to its mid position BBC Scale using the tone generator and millivoltmeter as described above adjust mixer levels for a reading of OdBu on the millivoltmeter from a main output Switch the appropriate meter to the selected output and adjust VR1 for a reading of 4 Increase the output signal to 8dBu and adjust VR2 for a reading of 6 Decrease the output signal to 8dBu and adjust VR3 for a reading of 2 Repeat this procedure until an accurate set of readings is obtained without further adjustment to any of the presets being required Now check all points 1 to 7 on the scale to determine whether they are within specification N10 Scale for a meter calibration of TEST 0dBu With a main output signal of 6dBu adjust VR1 to give a meter reading at 6 Increase the signal to 6dBu and adjust VR2 to obtain a meter reading at 6 Lower the output signal to 18dBu and adjust VR3 to obtain a meter reading at 18 Repeat th
31. tputs from AD147 are to be found on the connector panel Module connector 1 accepts balanced microphones Module connector 2 accepts balanced line level inputs XLR Pin 1 Shield Pin 2 Signal Pin 3 Signal In the case of an unbalanced line input pins 1 amp 3 should be connected Main 6 and auxiliary 5 outputs are electronically balanced and are at line level When driving unbalanced loads the mixer outputs may be safely unbalanced by connecting pins 1 amp 3 This will not lead to a loss of output level XLR Pin 1 Shield Pin 2 Signal Pin 3 Signal The unbalanced stereo return enters the mixer on two standard A type stereo jacks 3 left and right The unbalanced monitor outputs are on two standard A type stereo jacks 4 left and right at line level The monitor 2 headphones output appears on an A type stereo jack 8 This output is capable of driving 25R at OdB BALANCED JACK MONO UNBALANCED JACK STEREO UNBALANCED JACK Tip Signal Tip Signal Tip Left Signal Ring Signal Ring Shield Ring Right Signal Sleeve Shield Sleeve Shield Sleeve Shield SUBI 7 is a subsidiary connector for use with a Nagra IVS TUCHEL Pini ROUT Pin5 NC Pin2 NC Pin6 NC Pin3 LOUT Pin7 Ov GND Pin4 NC The 6 pin XLR connector 9 carries all signals to and from an outstation boom operator director etc The return appears only on the headphones output XLR Pin 1 Audio ground Pin 2 Send Pin 3 Send Pin 4 Re
32. usly charge a set of NICADs a current capability of at least 650mA is required It is poor practice to run a PSU at its limit therefore we recommend a minimum of 750mA Audio Developments AD100 09 PSU is a suitable unit WARNING When NOT using the PSU AD100 09 supplied for the mixer ensure your 4 pin XLR is correctly wired to match the POWER IN connector Failure to do so may result in the breakdown of the internal DC DC converter Make this check even if using a PSU which may have been supplied to you in the past eg AD100 06 AD100 05 PSU is NOT suitable for use with an AD147 mixer and must not be used ELECTRICAL REFERENCE MAX GAIN MAX INPUT LEVEL INPUT IMPEDANCE MIC POWERING MAX OUTPUT OUTPUT IMPEDANCE FREQUENCY RESPONSE EQUALISATION HIGH PASS FILTER HARMONIC DISTORTION OVERLOAD INDICATOR CROSSTALK NOISE LIMITER TECHNICAL SPECIFICATION OdB 775mV at 1kHz unless otherwise stated MIC 85dB LINE 50dB MIC amp MAX GAIN 42dB LINE amp MAX GAIN 7dB MIN GAIN 0 MIN GAIN 30dB RETURN STEREO amp TB 24dB MIG gt 1k5R LINE gt 10kR RETURN gt 100kR STEREO amp TB 48v PHANTOM and 12v TONADER 24dBm 600R LOAD L R amp AUX 1 2 18dBm 600R LOAD MONITOR 1 2 amp TB SEND ELEC BALANCED UNBALANCED 60R L R amp AUX 1 2 lt 20R MONITOR 1 2 lt 20R TB SEND 0 1dB 20Hz to 20kHz MAIN SIGNAL amp AUXILIARY PATHS 0 1 5dB 20Hz to 20kHz MONITOR PATHS 3 BAND LF

AD147

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