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Tube Stage Drive and Peak LEDs. 

 
These LEDs indicate the drive level to the tube, or valve, stage. The Drive LED is a 
variable  intensity  indicator,  starting  to  glow  when  the  tube  harmonic  distortion  is 
around 1%, and being fully illuminated at approximately 5% harmonic 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. 
 

Output Peak LED. 

 
Each  channel  has  an  output  Peak  LED  adjacent  to  the  VU  meter.  These  LEDs 
complement the average reading VU meter, and are useful for monitoring the output 
prior to sending to a DAW, for example. The Peak LEDs illuminate at an output level 
of +19dBu. 
 
 
 
 

 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 

Summary of Contents for Ebony A1

Page 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...

Page 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...

Page 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...

Page 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...

Page 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...

Page 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...

Page 7: ...6 BLOCK DIAGRAM...

Page 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...

Page 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...

Page 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...

Page 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...

Page 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...

Page 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...

Page 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...

Page 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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