Korg Prologue 8 square wave "jittery"
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Korg Prologue 8 square wave "jittery"
Hi everyone, I point out what I think is an anomaly on my korg prologue 8 (but not only that, there are other people who complain about the same "defect"), purchased last July. The strange behavior occurs on the square wave of the VCOs, that is most of the time (not always) it sounds as if there was a vibrato, tremolo type modulation on the pitch of the oscillators, very annoying. Of course I have zeroed and disabled any modulation on the oscillators, including the effects built into the musical instrument. Some instability is normal, but this square wave behavior is something else.
There is a wobble on all waveforms, you even see it in display that it's not all perfect still image. I see it and I hear it.
For me it's a little bit more as Prologue just is powered up, and diminish in 20 minutes or so when fully warm. But fully audible all the time.
If you don't like this - get a digitally controlled oscillator synth - DCO based.
Which often in turn have settings to emulate VCO wobbliness - funny isn't it.
It's a desired feature getting all analog with VCO.
Mixing oscillators which each has a wobbliness is part of creating the phat sound you don't get from digitally controlled oscillators where everything is in phase according to a clock.
- compare a bit to what happends as you detune oscillators, but in a dynamic random fashion.
- you are getting harmonics not there otherwise
DeepMind, Roland SH-32 and others I had/have have settings to create wobbliness. Osc-drift and rate.
From DeepMind manual
"OSC-DRIFT - This option allows you to recreate the oscillator tuning drift
that vintage analog synthesizers have.
As you increase the OSC-DRIFT value, the pitch of the oscillators will be slowly modulated at random.
OSC-DRIFT is applied to both OSC 1 and OSC 2.
The OSC-DRIFT range is from 0 to 255, and the default setting is 0 (no drift).
• PARAM-DRIFT - This option allows you to recreate the drift that many
parameters in a vintage analog synthesizers have.
As you increase the PARAM-DRIFT value, the drift distances will increase.
Note: The parameters which DRIFT is applied to are:
• OSC1 PITCH MOD, OSC1 PWM, OSC2 PITCH MOD, OSC2 TONE MOD,
• VCF FREQ, VCF RES, VCF ENV DEPTH, VCF LFO DEPTH, VCA ENV DEPTH,
• MOD ENV DEPTH
The PARAM-DRIFT range is from 0 to 255, and the default setting is 0.
• DRIFT-RATE - This controls the RATE at which the OSC-DRIFT and
PARAM-DRIFT operate. It is important to note that each voice has
independent random DRIFT generators for the OSC-DRIFT and the
PARAM-DRIFT, to more closely replicate the characteristics of a
vintage synthesizer.
The rate is controlled by a random timer which generates a ramp between
a multiplier of 1x and a multiplier of 2x the rate set by the DRIFT-
RATE parameter.
The OSC-DRIFT range is from 0 (25 ms-50 ms) to 255 (2.5 s-5.0 s). The default
OSC-DRIFT setting is 0.
To summarize, if the DRIFT-RATE is at 0, each “drift” will be a random time
between 25 and 50 ms, and then the parameter drifts to another random
value. At 255, each “drift” will be a random time between 2.5 s and 5.0 s and
then the parameter drifts to another random value."
For me it's a little bit more as Prologue just is powered up, and diminish in 20 minutes or so when fully warm. But fully audible all the time.
If you don't like this - get a digitally controlled oscillator synth - DCO based.
Which often in turn have settings to emulate VCO wobbliness - funny isn't it.
It's a desired feature getting all analog with VCO.
Mixing oscillators which each has a wobbliness is part of creating the phat sound you don't get from digitally controlled oscillators where everything is in phase according to a clock.
- compare a bit to what happends as you detune oscillators, but in a dynamic random fashion.
- you are getting harmonics not there otherwise
DeepMind, Roland SH-32 and others I had/have have settings to create wobbliness. Osc-drift and rate.
From DeepMind manual
"OSC-DRIFT - This option allows you to recreate the oscillator tuning drift
that vintage analog synthesizers have.
As you increase the OSC-DRIFT value, the pitch of the oscillators will be slowly modulated at random.
OSC-DRIFT is applied to both OSC 1 and OSC 2.
The OSC-DRIFT range is from 0 to 255, and the default setting is 0 (no drift).
• PARAM-DRIFT - This option allows you to recreate the drift that many
parameters in a vintage analog synthesizers have.
As you increase the PARAM-DRIFT value, the drift distances will increase.
Note: The parameters which DRIFT is applied to are:
• OSC1 PITCH MOD, OSC1 PWM, OSC2 PITCH MOD, OSC2 TONE MOD,
• VCF FREQ, VCF RES, VCF ENV DEPTH, VCF LFO DEPTH, VCA ENV DEPTH,
• MOD ENV DEPTH
The PARAM-DRIFT range is from 0 to 255, and the default setting is 0.
• DRIFT-RATE - This controls the RATE at which the OSC-DRIFT and
PARAM-DRIFT operate. It is important to note that each voice has
independent random DRIFT generators for the OSC-DRIFT and the
PARAM-DRIFT, to more closely replicate the characteristics of a
vintage synthesizer.
The rate is controlled by a random timer which generates a ramp between
a multiplier of 1x and a multiplier of 2x the rate set by the DRIFT-
RATE parameter.
The OSC-DRIFT range is from 0 (25 ms-50 ms) to 255 (2.5 s-5.0 s). The default
OSC-DRIFT setting is 0.
To summarize, if the DRIFT-RATE is at 0, each “drift” will be a random time
between 25 and 50 ms, and then the parameter drifts to another random
value. At 255, each “drift” will be a random time between 2.5 s and 5.0 s and
then the parameter drifts to another random value."
MIDI gear: Sequential REV2.16, Prologue-8, Hammond XK-3C, Kawai MP7SE piano, Nord Lead 2X, Roland D-05
I also have the minilogue and it's normally unstable, and that's fine! I know perfectly well the difference between VCO and DCO. On the prologue it is different, yes it does on all waveforms, but you notice a lot more on the square. It's a very fast tremolo, it's not the classic thermal drift of voltage controlled oscillators
The stabilizing parts of circuitry is tuned to behave optimal when warm.
I find nothing disturbing on my machine at least regarding this.
Assuming you run latest v2.10 firmware.
Could be you have to have machine serviced somehow. Analog circuit components have tolerances and all a bit different. Maybe production were a bit sloppy having machines run warm before releasing for delivery.
Mine is clearly less wobbly as fully warm.
I find nothing disturbing on my machine at least regarding this.
Assuming you run latest v2.10 firmware.
Could be you have to have machine serviced somehow. Analog circuit components have tolerances and all a bit different. Maybe production were a bit sloppy having machines run warm before releasing for delivery.
Mine is clearly less wobbly as fully warm.
MIDI gear: Sequential REV2.16, Prologue-8, Hammond XK-3C, Kawai MP7SE piano, Nord Lead 2X, Roland D-05
Yes, I have updated the firmware to version 2.10. I'll go to the shop where I bought it and try another one. From this forum and the gearslutz forum
http://www.korgforums.com/forum/phpbb2/ ... bbce6d782a
https://www.gearslutz.com/board/electro ... e-164.html[/img]
http://www.korgforums.com/forum/phpbb2/ ... bbce6d782a
https://www.gearslutz.com/board/electro ... e-164.html[/img]