JBL 5306 Technical Manual

Also see for 5306: Technical manual Technical manual

Service NotesPerformance ChecksA l l performance checks are in-cabinet procedures to be usedfar checking specifications after repair or for incoming qualitycontrol inspection. Note: AM measurements should be madew i t h the 5306 and test equipment power cords connected t oa nominal 120 V A C , 50/60 Hz line voltage.The f o l l o w i n g test equipment is recommended:A u d i o Test Osci I l a t o r - Krohn-Hite model 4 1 0 0 , orequivalent.Harmonic Distortion Analyzer—Hewlett Packard Model3 3 3 A , 3 3 1 A or equivalent.Intermodulation Distortion Analyzer—Crown Model I M A ,or equivalent.A C V o l t m e t e r — H e w l e t t Packard Model 4 2 7 A or equivalent.5. Voltage gain of the system can be checked by substitutingthe values in the formula A (dB) =20Log (-2?-)V 10 e , n6. Input voltage to the system can be measured by connect-ing the A C voltmeter at the input terminal.Total Harmonic Distortion1. Using the test set-up illustrated, replace the AC voltmeterw i t h the harmonic distortion analyzer at the 5306 o u t p u tterminals.•2. With the microphone gain control at maximum andMaster Gain at " 7 , " set the test oscillator at any frequencybetween 30 Hz and 20 kHz. Adjust amplitude t o indicate6.2V RMS (+18 dBm) on the distortion analyzer.3. Total harmonic distortion of the mixer should be less than0.2% on any input channel.OscillatorKrohn-Hite)4100> 150ft JTo MJcchannelundertest5306 MixerAC Voltmeter orHarmonic DistortionAnalyzerT o 4 0 d Bpad and «osci i latorOscilloscopeMicrophone input levels are as indicated for Total HarmonicDistortion levels of 1% and 0.2% at +78 dBm output with theMaster Gain at " 5 . "7 Configuration—Frequency Response and THDFrequency Response1. Connect the test oscillator t o any one of the six micro-phone inputs through a 40-dB pad w i t h a standardmicrophone cable. A pad is not necessary when testingthrough one of the t w o program inputs.Z Connect an AC Voltmeter and a 620-ohm, 1-watt loadresistor across o u t p u t terminals marked " 6 0 0 OBalanced." Note that the t w o center terminals shouldbe strapped.31 With one microphone channel and Master Gain at maxi-m u m , set the test oscillator frequency t o 1000 Hz andadjust its amplitude t o indicate 1.95V RMS (+8 dBm) onthe A C voltmeter.4. Using 1.95V RMS as a reference level, the mixer should bew i t h i n + 1.0 dB f r o m 20-20,000 Hz.Microphone Overload Indicator1. With the test oscillator still connected to any one of thesix microphone inputs, connect the A C voltmeter acrossthe o u t p u t of the oscillator.2. Set the microphone gain control at m a x i m u m , and theMaster Gain at " O " .3. Set the test oscillator frequency to 1000 Hz and increasethe amplitude until the overload indicator starts to flash.The A C voltmeter should read 40 mV nominal.640dB pad Zs=150A CannonXLR-3-12CHewlettPackard427A,333Aor 331AInput(s)Mic ;620• 1WAlternate Oscillator Setup: 2s=600il.Oscillator 40 dB oadKrohn-Hite4100l 6 2 K a•620 aTektronix|561B MainFrame, 3B4 iTime Base,;|3A6 VerticalAmplifierMicrophone Channel Distortion Characteristics—