Studer A1 - Page 16

A Series Active Monitor Speakers
E0/2 Contents Date printed: 29.02.00
4.4 A3 Service....................................................................................................................................................E4/13
4.4.1 A3: Settings on the PCB ........................................................................................................................E4/14
4.4.1.1 A3: Required Test Tools...................................................................................................................E4/14
4.4.1.2 A3: Initial Settings ...........................................................................................................................E4/14
4.4.1.3 A3: Powering Up..............................................................................................................................E4/14
4.4.1.4 A3: Supply Voltages.........................................................................................................................E4/14
4.4.1.5 A3: Input Gain Check and EQ Preadjustments..................................................................................E4/15
4.4.1.6 A3: Input Common Mode Rejection Ratio (CMMR) .........................................................................E4/16
4.4.1.7 A3: Quiescent Current Setting..........................................................................................................E4/16
4.4.1.8 A3: Woofer Amplifier Output...........................................................................................................E4/17
4.4.1.9 A3: Tweeter Amplifier Output..........................................................................................................E4/18
4.4.1.10 A3: Limiter Threshold......................................................................................................................E4/19
4.4.1.11 A3: Overheat Protection Check.........................................................................................................E4/19
4.4.2 A3: Checks on the assembled Unit.........................................................................................................E4/20
4.4.2.1 A3: Required Test Tools...................................................................................................................E4/20
4.4.2.2 A3: Initial Settings ...........................................................................................................................E4/20
4.4.2.3 A3: Insulation Check........................................................................................................................E4/20
4.4.2.4 A3: Measurement Setup in the Anechoic Room ................................................................................E4/21
4.4.2.5 A3: SPL and EQ Fine-Adjustment....................................................................................................E4/22
4.4.2.6 A3: Distortion Check........................................................................................................................E4/22
4.4.2.7 A3: Polarity Check ..........................................................................................................................E4/23
4.4.2.8 A3: Overall Phase Check..................................................................................................................E4/23
4.5 A5 Service....................................................................................................................................................E4/24
4.5.1 A5: Settings on the PCB ........................................................................................................................E4/25
4.5.1.1 A5: Required Test Tools...................................................................................................................E4/25
4.5.1.2 A5: Initial Settings ...........................................................................................................................E4/25
4.5.1.3 A5: Powering Up..............................................................................................................................E4/25
4.5.1.4 A5: Supply Voltages.........................................................................................................................E4/25
4.5.1.5 A5: Input Gain Check and EQ Preadjustments..................................................................................E4/26
4.5.1.6 A5: Input Common Mode Rejection Ratio (CMMR) .........................................................................E4/27
4.5.1.7 A5: Quiescent Current Setting..........................................................................................................E4/28
4.5.1.8 A5: Woofer Amplifier Output...........................................................................................................E4/28
4.5.1.9 A5: Mid-range Amplifier Output......................................................................................................E4/29
4.5.1.10 A5: Tweeter Amplifier Output..........................................................................................................E4/30
4.5.1.11 A5: Limiter Threshold......................................................................................................................E4/31
4.5.1.12 A5: Overheat Protection Check.........................................................................................................E4/31
4.5.2 A5: Checks on the assembled Unit.........................................................................................................E4/32
4.5.2.1 A5: Required Test Tools...................................................................................................................E4/32
4.5.2.2 A5: Initial Settings ...........................................................................................................................E4/32
4.5.2.3 A5: Insulation Check........................................................................................................................E4/32
4.5.2.4 A5: Measurement Setup in the Anechoic Room ................................................................................E4/33
4.5.2.5 A5: SPL and EQ Fine-Adjustment....................................................................................................E4/34
4.5.2.6 A5: Distortion Check........................................................................................................................E4/34
4.5.2.7 A5: Polarity Check ..........................................................................................................................E4/35
4.5.2.8 A5: Overall Phase Check..................................................................................................................E4/35
4.6 Appendix: Frequency Response Measurements .........................................................................................E4/36
4.6.1 General..................................................................................................................................................E4/36
4.6.2 Standing Waves, Reflections, and Smoothing.........................................................................................E4/36
4.6.3 MLS Technology for Frequency Response Measurements ......................................................................E4/37
4.6.4 Quasi-Anechoic Measurements and Low-Frequency Limitations............................................................E4/38
4.6.5 MLS Advantages ...................................................................................................................................E4/39
5 Diagrams ......................................................................................................................................E5