Configuration of the Ring Modulator
Please note: This procedure has not been verified by Black Corporation, it is purely my suggestion based on the trimming of similar ring modular
designs.
Remember, the RM controls for Attack, Decay, Sustain, Release should only be heard when the Depth slider is moved from minimum to maximum.
The Depth slider controls the amount those four controls add to the modulation.
The Modulation slider: When at the top or at minimum, only the source should he heard when a key is pressed. Sliding the Modulation control
down increase the amount of modulation introduced.
The Speed slider increases the frequency of the modulation: (0 to about 200Hz)
Sustain I & II
Envelope controls: Attack, Decay, Sustain and Release are much more enhanced or noticeable when this slider (right hand side of control panel) is
pushed from Min (bottom) to Max (Top). This control enables MIDI messages to be sent, so the expander should be connected between the
controller and the Deckard’s Dream. Calibration does not require this.
Calibration Process:
Setup:
Scope on pin 14 of IC2 (REF Signal Sine wave) and Pin 10 of IC1 (Triangle wave)
Plug headphones into the expander or use an amp
Set the volume up a bit (under headphones it can get loud so watch it)
SIG trim did not require much trimming.
REF Trim
:
The idea is that a Ring Modulator or Sonic Multiplier should only respond (with the REF signal), only when an audio signal is present on the SIG
channel. If there is no source there should be no sound.
Disconnect any source from the input jacks.
Set Modulation slider to max (all the way down)
Set Speed Slider to max.
Adjust REF trimmer until you can minimally hear any sound (you may not get rid of it all)
After all... multiplying anything by zero, should be zero. No SIG signal, no sound.
1) Low Frequency trim (0.2Hz trimmer)
Connect Keyboard (MIDI) to Decker’s Dream
Plug in a Deckard’s Dream into the Expander Audio input
Set Speed to Max
Set Modulation to Max
The frequency of the Sine wave and Triangle wave should be adjusted by the LF trim to about 200Hz
Moving Speed to Min results in a frequency of about 1 cycle over 4 seconds.
Note, even pressing a key on the MIDI keyboard, should not change the frequency, it should stay at about 200Hz when at Max.
2) High Frequency Trim (2.5KHz trimmer)
Keeping Speed and Modulation on Maximum
set RM Depth to Max
Set RM Sustain to Max
Press a key on the keyboard and hold it.
The frequency of the Sine wave and Triangle wave should be adjusted by the HF trim to about 2.5KHz
Now release the MIDI Key. The Frequency should drop back to 200Hz
You need to keep adjusting both trimmers until you get a good approximation of these two values.
Mine was finally set to LF = 210Hz, HF = 2.27KHz
Note Sliding the RM Sustain or Depth back to min puts the frequency back to about 200Hz
Keeping RM Sustain or Depth on Max and sliding the Speed back to min, results is a Frequency of about 2 cycles per second.
The minute a key is released, all current effects from the ring modulator should stop, or (depending on how close to the maximums are), the
envelopes, etc should decay back to silence fairly quick. This gets a little more pronounced when the added MIDI effect of the Sustain I or II is
added to this mix. Without any Sustain I or II, there is still some amount of signal seep when all the RM controls are maxed, and I have not yet
figured out how to stop it