Page 1: Table Of Contents
CONTENTS SCENARIO INTRODUCTION UNPACKING VISUAL INSPECTION SPECIFIC POINTS IMPORTANT SAFETY INSTRUCTIONS POWERING TECHNICAL SPECIFICATION EQUALISATION CURVES BLOCK DIAGRAM CONNECTOR PANEL CONNECTIONS INPUT MODULE OUTPUT MODULE ADJUSTMENTS AND CALIBRATIONS AD100-09 POWER SUPPLY UNIT CUSTOMER NOTES AND FACTORY MODIFICATIONS TECHNICAL LIBRARY SCENARIO...
Page 2 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.
Page 3 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.
Page 4: Introduction
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.
Page 5 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.
Page 6: 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.
Page 7: Powering
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.
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Page 9: Technical Specification
TECHNICAL SPECIFICATION - ELECTRICAL REFERENCE 0dB=775mV at 1kHz unless otherwise stated. MAX GAIN 80dB LINE 50dB MAX INPUT LEVEL MIC @ MAX GAIN -44dB @ MIN GAIN + 6dB LINE @ MAX GAIN -14dB @ MIN GAIN +20dB STEREO-RETURN +18dB TB RETURN +18dB INPUT IMPEDANCE...
Page 10  10dB @ 100Hz MF:  15dB CENTRE FREQUENCY 2k5Hz Q=1.2 HPF: PRE-TRANSFORMER 12dB/OCTAVE -3dB @ 150Hz -3dB @ 90Hz OUTPUT LIMITER THRESHOLD +8dB RATIO ATTACK 2 SETTINGS INTERNALLY SWITCHABLE 0.8mS RELEASE 2 SETTINGS INTERNALLY SWITCHABLE 250mS 80mS FACTORY SETTING: SLOW CURRENT CONSUMPTION 180mA (6 INPUT)
Page 11: Equalisation Curves
TECHNICAL SPECIFICATION - MECHANICAL SIZE 6 I/P 8 I/P 10 I/P 12 I/P ALL DIMENSIONS IN MILLIMETRES WEIGHT 6 I/P 8 I/P 10 I/P 12 I/P ALL WEIGHTS IN KILOGRAMS EQUALISATION CURVES...
Page 12 AD 245 HIGH AND LOW EQ 1000 10000 100000 FREQUENCY AD 245 MID EQ AND HPF 1000 10000 100000 FREQUENCY...
Page 13: Block Diagram
BLOCK DIAGRAM...
Page 14: Connector Panel
CONNECTOR PANEL (1) Mono output XLR (2) Stereo output XLRs (L & R) (3) Mic/Line input XLRs (4) Headphone monitor jack (5) External DC power input (6) Off/On switch (internal and external) (7) Stereo-return jacks (L & R) and calibration preset (8) Subsidiary connector (9) Reverse talkback preset...
Page 15 All input and output impedances and levels are to be found in the TECHNICAL SPECIFICATION. All inputs to, and outputs from AD245 are to be found on the connector panel. Module connector (3) accepts balanced microphones and balanced line-level inputs. XLR (input &...
Page 16 External powering of the mixer is via a 4-pin XLR (5). Pin 1 Pin 3 Pin 2 Charge Pin 4 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.
Page 17: Input Module
MICROPHONE/LINE INPUT MODULE (1) Microphone power (2) Line input (3) Input-gain control (4) Phase change (11) High-frequency control (5) High-pass filter (12) Mid-frequency control (6) EQ Selector (13) Low-frequency control (7) Panoramic potentiometer (8) Pre-fade listen (9) PFL indicator LED (10) Overload indicator (14) Channel fader...
Page 18 PICO - selector switch (6). Because of the inherent inaccuracy of the centre-detent mechanism, it is not Audio Developments’ practice to fit such devices to equaliser amplitude controls - HF (11), MF (12), LF (13).
Page 19: Output Module
OUTPUT MODULE (4) Mixer ON LED (5) Battery indicator (1) Meter 1 (6) Meter illumination (7) L-R or MON to meters (8) Line-up tone (9) 1kHz or 10kHz line-up tone (2) Meter 2 (10) Limiter link (11) Limiter LEDs (12) Output limiters (13) Direct or Return to HP (14) Left only Matrix...
Page 20 This module controls the level of main and monitor output signals and metering of the output and monitor signals (including PFL). Calibration is achieved when the output faders (3) are at maximum. The upper meter (1) reads left output, the lower meter (2) right output when switch (7) is in its L-R position.
Page 21 Line-up tone, when selected (8), replaces the normal signals on the main output. The frequency of the line-up tone may be selected between 1kHz and 10kHz (9). Line-up tone is calibrated on the (BBC-scaled) meters to PPM4, giving a line-output level of 0dBu with the output faders set to maximum.
Page 22: Adjustments And Calibrations
ADJUSTMENTS AND CALIBRATIONS Meters - are to broadcast specification and either a VU or a PPM may be selected. A choice of 3 scales is available for the PPM: BBC, N10, SDR. Line-up-tone oscillator - the preset (VR6) that adjusts its level at the output of the mixer is mounted on the output module printed circuit board.
Page 23 BBC scale - using the tone generator and millivoltmeter as described above, adjust mixer levels for a reading of 0dBu, on the millivoltmetez, from a main output. Select the meters to L-R and adjust VR1 for a reading of 4. Increase the output signal to +8dBu and adjust VR2 for a reading of 6.
Page 24 Main-output limiters - calibration involves two presets per output. Using the 'L' output as the example … Biasing and threshold are adjusted as follows: VR5 biases the limiter circuit to the point of correct operation and VR4 sets the threshold. (Labelled SET 0 and THR respectively.) With no signal present, VR5 should be adjusted to give a reading in the...
Page 25: Customer Notes And Factory Modifications
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.
Page 26: Technical Library
TECHNICAL LIBRARY...

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