U1127 User`s Manual
Contents
1. Hz and 20 kHz gain remains constant with a 0 005 dB tolerance and phase remains constant with a 1 tolerance When omnidirectional microphones are used the extent of the bandwidth allows a pick up of infra bass sounds generally produced by air conditioning of large halls or by wind during outdoor recording Even though these sounds are outside the audible range they can overload the input stage of the preamplifier or the equipment to which it is connected Whatever the frequency of these signals the overload led lights up at least 6 dB before overload of the preamplifier But they are no use to detect overload of equipment connected after the preamplifier Thus is may be necessary to use a low cut filter or to use pressure gradient microphones which hardly transcribe bass signals carried directly through the air However these transducers are very sensitive to both low frequency mechanical vibrations transmitted by contact and to air turbulence 20 Hz 80 Hz 140 Hz Positions In order to attenuate low frequencies three low cut filters can be used Depending on the position of the selector frequencies below 20 Hz 80 Hz or 130 Hz are attenuated by a first order filter This filter uses an active electronic circuit and is based on a substractive principle This system keeps a very high signal to noise ratio even when a filter is activated Overload led may light up if the signal at the output of the filter is great even in the2. FRONT PANEL 6 G GAIN 6 8 Gain selector 8 GENERALITIES 2 H Headroom 8 INA 6 IN B 6 INPUT AND OUTPUT LEVELS 8 Input protection system 8 L LEMO 13 Lithium battery 11 Low cut filter 9 14 M Maximum input level 8 Maximum output level 8 N Nickel Cadmium battery 11 Nominal output level 8 ON 6 9 Option 8 Oscillator 8 OUT A 7 OUT B 7 Output Level 8 Overload 6 8 Phantom power 10 Phantom power switches 10 Phase rotation 9 POWER ADAPTER 13 R REAR PANEL 7 Replace batteries 11 U U8111 13 X XLR connector 6 7 Z Zinc Carbone batteries 12 MCN AUDIO U1127 MICROPHONE PREAMPLIFIER MCN AUDIO On line WWW INCN AUU000 com Document Code UM EV U1127A V4 15
3. MCN AUDIO 1127 STEREO MICROPHONE PREAMPLIFIER USER S MANUAL OPTIONS Standard Oscillator 1000 Hz Standard Oscillator 12 dB Option 01 Oscillator 800 Hz Option 02 Oscillator 0 dB ACCESSORIES 08111 SERIAL NUMBER External Power Block 12 V 1 A MCN AUDIO U1127 MICROPHONE PREAMPLIFIER TABLE OF CONTENTS GENERAL WARRANTY SPECIFICATIONS SCHEMATIC FRONT PANEL REAR PANEL INPUT AND OUTPUT LEVELS GAIN OSCILLATOR BANDWIDTH PHANTOM POWER 10 BATTERIES 11 BATTERY LIFE 12 POWER ADAPTER 13 INDEX 14 O 0000 CO PD Due to permanent technical improvements specifications listed here can change Without prior notification MCN AUDIO U1127 MICROPHONE PREAMPLIFIER 2 GENERAL The U1127 is a high quality compact microphone preamplifier designed for professional use It can handle dynamic or electrostatic microphone level signals For the later a 12 V or 48 V phantom power can be supplied The low impedance of the floating balanced outputs allows the use of long cables without signal loss This unit is the ideal complement of a DAT recorder or a Betacam camera for which it is an alternative to high performance input stages The extended bandwidth the high signal to noise ratio and the precision of the calibrated gain make it useful for acoustic measurements MCN AUDIO U1127 MICROPHONE PREAMPLIFIER WARRANTY This equipment is warranted against defects in material and workm
4. ONE PREAMPLIFIER 11 BATTERIES To replace batteries Open the battery compartment using a coin to turn the lock Remove the compartment lid Insert 8 1 5 Volt LR6 AA AM3 alkalin batteries in the compartment Place the ribbon beneath the batteries it will aid the easy removal of the batteries Putthe lid back on the compartment using gentle pressure and turn the lock To remove the batteries use the ribbon to extract the first ones Replace the 8 batteries at the same time Do not use Nickel Cadmium or Lithium batteries if their nominal voltage is different to 1 5 V Observe batteries polarity However inverting the polarity of a battery will not cause any damage to the preamplifier When the preamplifier is not going to be used for a long period or if it is run on an external power source remove the batteries It is advisable to remove the batteries to keep them from discharging or to avoid electrolyte leakage which could corrode the electronic circuits MCN AUDIO U1127 MICROPHONE PREAMPLIFIER 12 BATTERY LIFE A set of 8 alkaline batteries should last a minimum of 8 hours of continuous use at a 20 C room temperature If used one hour a day the cumulative battery life is of 9 hours Should the battery voltage be insufficient the ON led will flash on the front panel of the preamplifier When this led starts flashing there are 15 minutes of power left Using the preamplifier in very cold conditions reduces bat
5. U1127 preamplifier with an external power source It is connected to the EXTERNAL POWER inlet on the preamplifier rear panel It is not necessary to remove the batteries when the preamplifier is run on external power However if run for prolonged periods or exclusively on external power it is preferable to remove used batteries from their compartment as they may leak and greatly damage the preamplifier s circuit Connecting or disconnecting the power adapter may be done even with the preamplifier running This does not lead to any audible noise at the preamplifier output The U8111 power adapter delivers a constant filtered and stabilized voltage of 12 V 1 A A slight increase in the temperature of the unit when operating is normal If the preamplifier is connected to a different power adapter it should strictly comply to the U8111 specification A polarity inversion is harmless to the preamplifier The male connector used is of the following type LEMO FGG1B304CLAD52 EXTERNAL Connector Pinout POWER Rear view II 1 OV 2 Reserved Do not connect 3 Reserved Do not connect 4 12 VDC 1A Pins 1 2 3 or 4 must not be connected to the ground of the preamplifier as such connection is made internally MCN AUDIO U1127 MICROPHONE PREAMPLIFIER INDEX A A 6 Alkaline batteries 12 B B 6 BANDWIDTH 9 BATTERIES 11 BATTERY LIFE 12 C Connector Pinout 13 E EXTERNAL POWER 7 13 F FILTER 6 Frequency 8
6. absence of a signal at the output of the preamplifier These led light up 6 dB before the active filter maximal output level MCN AUDIO 01127 MICROPHONE PREAMPLIFIER 10 PHANTOM POWER Phantom power integrated in the U1127 preamplifier can be switched to either 12 V or 48 V depending on the microphone used or switched off altogether The factory default is phantom power active and set to 48 V Make sure that the phantom power voltage value is compatible with your microphones before connecting them to the preamplifier Should an electronic circuit be connected to the inputs of the preamplifier it will probably be necessary to switch off the phantom power to prevent damage at the output stage of this equipment t t 12V Y 48v A OFF Y ON The phantom power switches are located inside the battery compartment To change the switches settings use a small screwdriver or a small metallic pin such as a straightened paperclip It is best to change these settings with the power turned off or when the microphones are not connected to the preamplifier When the phantom power is activated the connection or disconnexion of a microphone will cause a transient as high as 30 volts at the output of the preamplifier This phenomenon is normal and unavoidable It is harmless for the preamplifier itself Make sure that the equipment connected to the preamplifier can handle this transient MCN AUDIO U1127 MICROPH
7. anship for a period of five 5 years from date of delivery The warranty will be voided if the unit is tampered with or serviced by unauthorized personnel MCN AUDIO U1127 MICROPHONE PREAMPLIFIER SPECIFICATIONS INPUTS Impedance RF Filter Gain Maximum level Supply Connector OUTPUTS Impedance Protection Nominal level Maximum level Connector TRANSFER Crosstalk A B Gain mismatch A B Bandwidth Low cut filter Phase roll off Common mode rejection Input noise Distortion OSCILLATOR Frequency Level Distortion GENERAL Power supply Battery life expectancy Pilot lights Temperature Case size Weight Transformerless electronically balanced 7710 Ohms 220pF differential included 10 20 30 40 50 60 dB 20 8 dBm 12 Volts peak phantom 48 V or 12 V switchable XLR female Transformerless electronically balanced 600 Ohms minimum against phantom power short circuit to ground 4 dBm 25 dBm under 600 Ohms XLR male gt 85 dB from 0 to 20 kHz lt 0 2 dB from 20 Hz to 20 kHz 10 Hz to 30 kHz 0 1 dB 0 7 Hz to 70 kHz 3 dB selectable 20 Hz 80 Hz 140 Hz first order lt 1 from 20 Hz to 20 kHz no filter selected 60 dB at 20 kHz gain 10 dB 88 dB at 20 kHz gain 30 dB 112 dB gain 10 dB source 150 Ohms 130 dB gain 30 dB source 150 Ohms typical 0 0007 96 at 1 kHz nominal level standard 1000 Hz 3 Hz optio
8. ctive On the OSC position the signal of the oscillator is present at the output of the preamplifier at the reference level The input signal is disconnected from the outputs The Microphone power is still active The blue ON pilot light is lit when the unit is ON It flashes when power is low The green EXT pilot light lights when the preamplifier is powered by an external power source through the connector on the rear panel Channel A overload pilot light This led lights when the signal is 6dB below clipping that is 14 dB at the output or when the signal of the internal filter is 6 dB below clipping Channel B overload pilot light This led lights when the signal is 6 dB below clipping that is 14 dB at the output or wher the signal of the internal filter is 6 dB below clipping MCN AUDIO U1127 MICROPHONE PREAMPLIFIER 7 REAR PANEL OUT A Channel A output 1 Ground 3 pin male XLR connector 2 Hot Pin 1 is connected to the metallic frame 3 Cold OUT B Channel B output 1 Ground 3 pin male XLR connector 2 Hot Pin 1 is connected to the metallic frame 3 Cold EXTERNAL External power supply connector POWER Connects to the U8111 power supply MCN AUDIO U1127 MICROPHONE PREAMPLIFIER 8 INPUT AND OUTPUT LEVELS The maximum input level is 20 8 dBm Above this level the input protection system limits the signal In this mode the input impedance drops to about 200 Ohms This system is designed to limit the transient that
9. is cause when the microphones are connected or disconnected while the phantom power is active The output nominal level of the preamplifier is 4 dBm 0 dBm 0 775 V The maximum output level is 20 dBm and clipping occurs at about 25 dBm The overload led light 6 dB before maximum output level that is 14 dBm Thus the headroom before clipping is 11 dB GAIN The nominal output level of the preamplifier is 4 dBm The real gain value is the value shown on the gain selector plus 4 dB Switch Position Actual Gain 10 dB 14 dB 15 dB 19 dB 20 dB 24 dB 25 dB 29 dB 30 dB 34 dB 35 dB 39 dB 40 dB 44 dB 45 dB 49 dB 50 dB 54 dB 55 dB 59 dB 60 dB 64 dB The gains are adjusted to a 0 3 dB tolerance The gain difference between channel A and B is less than 0 2 dB OSCILLATOR The frequency of the oscillator is adjusted to a 3 Hz tolerance The nominal output level of the preamplifier being 4 dBm the output level of the oscillator is increased by 4 dB A 1 5 distortion is normal Frequency standard 1000 Hz 3Hz option 01 800 Hz 3Hz Output Level standard 12 dBm actual level 8 dBm option 02 0 dBm actual level 4 dBm MCN AUDIO U1127 MICROPHONE PREAMPLIFIER 9 BANDWIDTH ON Position When no low cut filter is active the bandwidth of the U1127 is deliberately very large so as to minimize gain differences phase rotations which normally occur at the end of the audible range In this mode between 20
10. n 01 800 Hz 3 Hz standard 12 dBm option 02 0 dBm typical 0 5 96 8 alkaline battery 1 5 V AA LR6 External 12 V 400 mA on LEMO connector minimum 8 hours permanent use according to the type of the microphones connected and temperature ON EXT external supply PEAK 6 dB before saturation BATTERY LOW battery exhausted 30 C 60 C 105 x 45 x 205 mm 1150 g batteries included MCN AUDIO U1127 MICROPHONE PREAMPLIFIER 5 SCHEMATIC OSCILLATOR OUTPUT OUT A INA HF STAGE OUT B INB FILTER PREAMPLIFIER 20Hz 80Hz 140Hz bd OVERLOAD FILTER DETECTION MICROPHONE POWER 412V 48V DC DC CONVERTEUR OFF lt 7 EXTERNAL POWER BATTERIES channels are identical MCN AUDIO U1127 MICROPHONE PREAMPLIFIER 6 FRONT PANEL IN B GAIN ON FILTER FILTER Channel A input 1 Ground 3 pin XLR connector 2 Hot Pin 1 is connected to the metallic frame 3 Cold Channel B input 1 Ground 3 pin XLR connector 2 Hot Pin 1 is connected to the metallic frame 8 Cold Gain selection applied to the input signal Rotary selector ON OFF OSCillator On the OFF position the unit is turned off On the ON position is turned on Microphone power is active No filter is active On the 20 Hz position the 20 Hz filter is active On the 80 Hz position the 80 Hz filter is active On the 130 Hz position the 130 Hz filter is a
11. tery life Using Zinc Carbone batteries instead of alkaline batteries significantly reduces the autonomy of the preamplifier NiCad rechargeable batteries which have a 1 25 V voltage per cell have a short life expectancy Note that using the U8111 external power adapter does not recharge the batteries placed in the battery compartment The power converter circuit inside the U1127 preamplifier has been designed to run normally until the batteries are completely drained Thus used batteries should not be left inside the preamplifier as the could leak and greatly damage the circuits of the preamplifier Life expectancy is determined by the type of the microphones connected to the preamplifier Therefore the higher the microphone consumption the shorter the battery life expectancy Values are given for two 48 V 4 mA microphones The power converter circuit inside the U1127 preamplifier has been design to run normally until the batteries are completely drained Thus used batteries should not be left inside the preamplifier as they could leak and greatly damage the circuits of the preamplifier When replacing the batteries please dispose of the used batteries in appropriate waste bins Even discharged batteries can be partially recycled Respect the environment Do not throw away batteries in the country side whatever their type MCN AUDIO U1127 MICROPHONE PREAMPLIFIER 13 U8111 POWER ADAPTER The U8111 power adapter allows use of a
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