Samstag, 26. Februar 2005     DIY |  studio |  mail

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UREI 1176 Calibration

Note: There are no user serviceable parts inside the Universal Audio 1176LN. Unit calibration as well as repair should only be performed only by qualified service personnel. These calibration procedures are provided only for use by qualified service technicians.

Q Bias
The compression threshold is set using R59. Under normal circumstances, this control doesnot need to be adjusted. The threshold is dependent upon the specific characteristics of the VVR FET (Q1), and it will be necessary to re-adjust it if Q1 is changed.

The following procedure is used to set Q bias:

  • Select either +4 or +8 output metering
  • Adjust R59 fully counterclockwise (CCW)
  • Apply a sine wave signal to the limiter
  • Use the Input and Output Controls for 0dB output Slowly adjust R59 CW until the output decreases 1.0 dB

Meter Driver Null
A multimeter is needed to perform this calibration procedure.

  • Disconnect any input and output connection on the 1176LN
  • Set multimeter to measure dc volts
  • Depress the Meter GR pushbutton Adjust 0 set potentiometer, R71 (located on the front panel) so that the meter reads near 0 dB
  • Connect the multimeter across R74 ! Adjust R75 for a minimum voltage reading ! Disconnect the multimeter
  • Readjust 0 set potentiometer, R71 so that the meter reads 0 dB

Zero Set
R71, located on the front panel is used to zero the meter.
Adjust this potentiometer if the meter needs to be recalibrated.

Stereo Interconnection
Using the 1176SA, two units may be connected for stereo operation. Use the following procedure to calibrate the 1176 stereo adapter:

  • Remove the signals from both 1176 units
  • Disable the gain reduction on each limiter (rotate both ATTACK controls fully CCW)
  • Connect the 1176-SA to both limiters (This requires two RCA style cables.)
  • Use the METER function pushbutton switches to set both units into GR mode
  • Adjust the potentiometer on the 1176-SA until both meters read 0dB ! If it is not possible to zero both meters, reverse the stereo interconnect cables and repeat the preceding step.