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Behringer CAT Customer Support Bulletin

Behringer CAT Customer Support Bulletin

Legendary duophonic analog synthesizer

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Synthesizers and Samplers
CAT
Legendary Duophonic Analog Synthesizer
with Dual VCOs, 4 Mixable Waveforms,
External Signal Processor, 16-Voice Poly Chain,
and Eurorack Format
User Support Bulletin
Introduction
The unit is carefully calibrated at the factory. The performance may change over time or due to environmental changes,
and the following recalibration procedures can be used to bring it back to its factory settings. If you do not feel comfortable
doing these calibrations, then we recommend they are done by an experienced audio service technician. This is especially true
for those units that need to be opened to gain access to voltage test points and calibration potentiometers.
CAUTION: Incorrect calibration or damage to the delicate adjustment potentiometers may lead to the unit
becoming inoperable.
Note: Although re-calibration will not invalidate the warranty, any damage caused during re-calibration may invalidate
the warranty.
Equipment required
1. Small insulated trimmer screwdriver.
2. Small Phillips screwdriver.
3. A flat sheet of cardboard or another insulator as wide as the unit. (This will help prevent damage to the top panel when it is
inverted and resting on the bottom chassis).
4. Digital DC Voltmeter with a scale that can display accurately to 0.001 V.
5. Guitar tuner
6. An external MIDI keyboard of at least 6 octaves including A1 and A7.
7. MIDI cable.
8. Pair of headphones or a sound system to monitor the main output.
Important Note:
Leave the unit turned on for approximately 30 minutes. This will allow the circuits time to warm up and the components and
performance to stabilize with temperature. Without this warm-up time, the calibrations will be inaccurate.
985-40000-01170 Rev.A
page 1 of 6
2021-02-02
Confidential, for internal use only. Not to be reproduced.

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Summary of Contents for Behringer CAT

  • Page 1 Synthesizers and Samplers Legendary Duophonic Analog Synthesizer with Dual VCOs, 4 Mixable Waveforms, External Signal Processor, 16-Voice Poly Chain, and Eurorack Format User Support Bulletin Introduction The unit is carefully calibrated at the factory. The performance may change over time or due to environmental changes, and the following recalibration procedures can be used to bring it back to its factory settings.
  • Page 2 Synthesizers and Samplers Preparation Follow all steps in the order in which they are presented. Remove all cables and connections to the unit. Remove the 8 screws holding the top panel to the chassis. Turn over the top panel to gain access to the bottom surface of the printed circuit board (pcb). Be careful not to strain the ribbon cables.
  • Page 3: Calibration Procedure

    Synthesizers and Samplers Calibration Procedure Oscillator Calibration using a guitar tuner: The positions of knobs and switches are shown in red on Figure 1. Connect a guitar tuner to the rear panel main 1/4" output. Please pay special attention to the FREQUENCY knobs of VCO1 and VCO2. Note that a pitch within 2 to 3 cents of the target frequency should be fine.
  • Page 4 Synthesizers and Samplers Figure 2 On your external keyboard, press the A5 key and adjust the VCO1 SCALE trimmer (VR41 on the bottom side) while observing the tuner display (A5-880Hz). Repeat steps 2 and 3 above until both notes are correct in the display. This may need to be repeated several times to get right.
  • Page 5 Synthesizers and Samplers Repeat steps 2 and 3 above until both notes are correct in the display. This may need to be repeated several times to get right. Turn off the VCO2 SAW fader. OCTAVE Calibration (factory mode) This calibration is done after the oscillator calibration. The positions of knobs and switches are shown in red on Figure 1.
  • Page 6 Technical specifications, appearances and other information are subject to change without notice. All trademarks are the property of their respective owners. Midas, Klark Teknik, Lab Gruppen, Lake, Tannoy, Turbosound, TC Electronic, TC Helicon, Behringer, Bugera, Oberheim, Auratone and Coolaudio are trademarks or registered trademarks of Music Tribe Global Brands Ltd.