Future Retro Revolution Owner Manual - Manual (Page 42)

CALIBRATIONS
TUNING AND CALIBRATING THE REVOLUTION
The Revolution provides three access holes on its front panel for calibrating the CV output and
tuning the oscillator. These trimmers are set at the factory but may need to be adjusted over time.
To make adjustments to these trimmers, we recommend using a 5/64” flat-blade screwdriver.
Before making any adjustments, turn the unit’s power on and let it warm up for at least 15 minutes.
CV OUT – T1
T1 is the trimmer for adjusting the control voltage generated by the sequencer and sent to the CV
OUT jack. Please note that if adjustments are made to this setting, you will need to recalibrate the
Scale, and Offset trimmers described below.
First create two different patterns, each containing only one note. The first pattern should be
programmed to play a pitch of C1, the second pattern should play a pitch of C6. If you have a
voltmeter, plug a short 1/4” cable into the CV OUT jack and connect the leads of your voltmeter to
the other end of the 1/4” cable. Play the pattern containing C1 and check the voltage being generated.
Play the pattern containing C6 and adjust T1 until the voltage generated is 5 volts higher than that of
C1. You may need toggle back and forth a few times checking the voltage of C1 and then adjusting
for C6 until the difference is exactly 5 volts.
If you don’t have a volt meter, connect the CV OUT and Gate OUT to a 1V/Oct synthesizer which is
properly calibrated. Play the two patterns containing C1 and C6 while adjusting T1 until the external
synthesizer plays the correct scaling. Note: This method is not as accurate as using a voltmeter.
OSCILLATOR SCALE – T2
To calibrate the oscillator’s scale you should first make sure that CV OUT is calibrated properly. If
you have an oscilloscope, connect a short 1/4” mono cable to the filter’s CV IN jack. Notice that this
jack is a stereo connector, and you will first plug the 1/4” cable all the way into this jack and then
pull it out until you feel it click once. The cable will then be plugged only half way into this jack.
Connect the probe of your oscilloscope to the other end of the 1/4” cable. You should now see the
oscillator’s waveform on the scope. You may need to increase the amplitude setting of your scope to
properly sync and view the waveform. You may also want to set the sequencer’s tempo to a range of
approximately 50 B.P.M.. Play a pattern containing only the pitches C1 and C2, and then adjust
trimmer T2 until the waveform generates a 2:1 ratio. Next play a pattern containing only the pitches
C1 and C3, and adjust T2 until the waveform generates a 4:1 ratio. Play another pattern containing
C1 and C4, and again adjust T2 until the waveform generates an 8:1 ratio. Use this same method for
C1 and C5 (16:1 ratio) and C1 and C6 (32:1 ratio) until they generate perfect octaves.
If you don’t have access to an oscilloscope, you can use a digital tuner to monitor the output pitch
while making adjustments so that the oscillator produces perfect octave changes.
OSCILLATOR PITCH OFFSET – T3
Trimmer T3 is used to offset the pitch produced by the oscillator. First make sure that the oscillator’s
Tune control is set to the mid position. Use a digital tuner to monitor the main output of the
Revolution. Play a pattern containing only a single note, let’s say with a pitch of C3. While this
pattern plays, adjust trimmer T3 until the oscillator produces a true C note. Make sure that the
transpose setting in the sequencer is set to 0 when making adjustments.
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