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OPERATION. 

 

Microphone Input 

 

The 2 XLR mic inputs are at the rear of the Ebony A1. Virtually any low impedance 
professional  microphone  can  be  used.  Condenser  microphones  will  require  the  48V 
phantom power button to be engaged for correct operation, but before using Dynamic 
and Ribbon microphones ensure that the phantom power is switched off.     
 

Instrument Input 

  
The  front  panel  instrument  input  socket  is  suitable  for  low  level  sources  such  as  hi 
impedance microphones, pick ups or passive guitars, and higher level sources such as 
active guitars and keyboards, as it is switchable to high or low sensitivity. 
 

Input Gain.  

  
The gain of the mic preamp stage is variable from +16 to +60dB. This is a very wide 
range, to cater for all types of microphone and recording situations, but care must be 
taken not to apply large, sudden changes in gain that may result in unexpectedly large 
output  signals.  It  is  quite  normal  to  have  to  apply  larger  amounts  of  gain  for  less 
sensitive  microphones,  such  as  dynamic  types,  and  similarly  apply  much  less  input 
gain  for  high  output  condenser  mics:  some  of  which  may  even  need  the  30dB  pad 
activated when recording very loud sources. 

 

30dB Pad Switch.  

  
Occasionally - when using sensitive condenser microphones - the source signal may 
be  too  loud  for  the  input  preamp.  In  this  situation,  to  avoid  any  overloading  or 
distortion of the mic preamp stage, the 30dB pad can be used to reduce the input gain 
to a more manageable level. The 30dB pad only applies to the microphone input.  
  

Phantom Power. 

 
+48V  phantom  power  is  available  at  the  mic  socket,  selected  by  a  front  switch. 
Phantom power should only be used in conjunction with suitable microphones. 
 

CAUTION:

   Operation of the phantom power switch, or plugging a microphone in or 

out with phantom power applied, may cause a click or thump in your loudspeakers.  
To prevent this happening, ensure that the system gain is set to minimum (e.g. on your 
mixing console fader or power amplifier), before operating the switch or plugging in a 
microphone. 

Содержание Ebony A1

Страница 1: ...T L Audio User Manual Ebony Series A1 Dual Pre Amp TL Audio Limited Letchworth England Tel 01462 492090 Fax 01462 492097 www tlaudio co uk email info tlaudio co uk...

Страница 2: ...7 Audio Inputs 7 Instrument Inputs 8 Outputs 8 Ventilation 8 OPERATION 9 Microphone Input 9 Instrument Input 9 Input Gain 9 30dB Pad Switch 9 Phantom Power 9 Tube Stage Drive and Peak LEDs 10 Output...

Страница 3: ...fers superior analogue processing to accompany a digital world Why Class A Class A circuits are designed with a constant current flowing through all of the transistors which is sufficient to drive the...

Страница 4: ...phase connections which form a differential pair independent of the ground or earth connection Noise particularly mains hum and high frequency interference can often be present in unbalanced systems d...

Страница 5: ...d a dedicated valve input stage Phase reverse and high pass filter switches are provided affecting both mic and instrument inputs The tube stage has a variable drive control with the signal level indi...

Страница 6: ...rved All mains wiring should be installed and checked by a qualified electrician Ensure the mains operating voltage stated on the rear panel is correct before connecting to the mains supply Never oper...

Страница 7: ...6 BLOCK DIAGRAM...

Страница 8: ...taken to an approved service centre Alternate supply voltages may also require a different power cable or mains plug If in doubt consult local electrical regulations Warning attempted operation on the...

Страница 9: ...as follows Pin 1 Ground screen Pin 2 Signal Phase or hot Pin 3 Signal Non Phase or cold If an unbalanced output is required pins 1 and 3 should both be connected to ground Ventilation The unit generat...

Страница 10: ...normal to have to apply larger amounts of gain for less sensitive microphones such as dynamic types and similarly apply much less input gain for high output condenser mics some of which may even need...

Страница 11: ...nic distortion The distortion is predominately second harmonic unless very high drive levels are used in which case the tube is eventually pushed into harsher saturation indicated by the tube Peak LED...

Страница 12: ...hould now start to hear some sound and as the output is increased the red signal LEDs will start to illuminate Set the output level to a comfortable level so that you are getting a good metered level...

Страница 13: ...Distortion THD Noise 0 025 20Hz to 20KHz 40dB gain Noise EIN 127dBu unweighted 22Hz to 22KHz 150 ohm source termination Instrument Input Tube input stage plus discrete Class A circuitry to output Gain...

Страница 14: ...Bu on output VU Meter Switchable to Channel 1 or 2 and Input or Ouput Nominal calibration 0VU 4dBu 10dB switch calibration 0VU 14dBu Power Requirements Internally set to 230V 50Hz or 115V 60Hz operati...

Страница 15: ...hip will be repaired free of charge The warranty excludes damage caused by deliberate or accidental misuse tampering operation on the incorrect mains voltage or without the correct type and value of f...

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