One of the nicest things about the MOTM format is that it has become a de facto open standard for modern modular systems. Synthesis Technology’s high standards for their designs, and the way they’ve refined classic designs, has made the format the cadillac of analog synthesis.
Compatible module designs are being made by Oakley Sound, Wise Guy Synth, Tellun Corp, and others. One of the first, and most interesting designs, comes from Encore Electronics. Their Universal Event Generator is a MOTM-compatible module that can serve many purposes within a modular system:
- It can work as an 8-stage envelope generator;
- It can operate as an LFO with customizable wave shape; and
- It works as an 8-step sequencer.
Each stage has an adjustable time and level. There’s also an LED for each stage that indicates the currently active stage, and it’s relative voltage.
The top switch on the UEG determines which of the three modes of operation will be active:
- Loop Only mode makes the UEG act like a LFO. It will cycle continuously, with levels and time dependant on the knob settings.
- One shot mode makes the UEG act like an envelope generator. It will with a gate input, and proceed from one stage to the next, with times and levels dependant on knob settings.
- Gated mode has several sub-options, determined by the second switch. There’s a link on the faceplate tying “Gated” to the second switch, to indicate the sub-level options. There are three gated functions:
- Gated-Step mode turns the UEG into an 8-stage sequencer. In this mode, Level knobs 1-7, and Time knob 8, control the level of the control voltage out.
- Gated-Finish Loop mode lets the UEG act like an envelope generator, but instead proceeding straight-through like in one-shot mode, it loops until the gate is released. Then it will finish the remaining stages and stop.
- Gated-Release tells the UEG to act like an envelope generator with a looped section. In this mode, releasing the gate signal jumps the UEG to stage 8 as soon as the current stage is complete.
There are three additional switches. The first two are used in the Loop Only, Gated-Finish, and Gated-Release mode. The switches tell the UEG to loop, starting at either 2, 3 or 4, and ending at 5, 6 or 7.
The remaining switch is the slope switch. It controls the shape of the output waveform. It can be linear, log, or step, as indicated on the panel.
There are four jacks:
- Gate – controls the speed of steps in Gated-Step mode, so the UEG can be used as a sequencer.
- TCV – the Time Control Voltage input can be used to increase the the length of the time values. This allows the UEG to be used as a voltage-controlled 8-step envelope generator.
- Out – this is the control voltage output.
- Trig out – this sends out a trigger pulse at the end of stage 8. This can be used to start up an event at the end/beginning of a sequence, LFO cycle, or envelope.
The final control is the Manual Gate button. When you push this button, it sends a gate signal to the UEG.
The Universal Event Generator is a complex and powerful module. This can make it a confusing module, unfortunately. Here are some tips for using it:
- Sequences – to use as a sequencer, try patching the output of an LFO square wave into the UEG Gate input. Patch the UEG Out into a 1v/octave FM input of your VCO. This make the output of the UEG control the pitch of your VCO. Adjust the LFO speed to your taste. Then adjust the Level knobs on the UEG to get the sequence you want. You can also patch the UEG output into things like a filter cut off, to have a sequenced filter sweep, or to a VCO’s pulse width mod, to vary the brightness of a sound rhythmically.
- Trig Out can be used to trigger a secong UEG. This can be used to create longer sequences. Another use is to trigger a sound every 8 steps. For example, you could trigger a drum sound at the beginning of each 8 step sequence.
- To use as an envelope generator, just patch a Gate in from a keyboard or other source, and patch the UEG Out to what you want to control, usually a VCA or VCF. The Time knobs will control how long each stage lasts, while the Level knobs will control how high the envelope goes.
- To use as a LFO, put it in Loop Only mode, patch the UEG Out into an oscillator, amplifier, filter or other module. If you patch the UEG into a VCO, the Time knobs will control the time it takes for the LFO to move from one stage to the next, while the Level knobs will control the voltage output at each stage.
There are two minor quibbles with the UEG. The first has to do with the Manual Gate button. This button was intended for manually stepping the sequencer through its stages so that you can easily set levels. It works fine for that. Unfortunately, it sometimes double-triggers. This makes the Manual Gate much less useful for live use, because you can never be sure of what will happen when you press it. Scott Juskiw, of the Tellun Corp, has put together info on a mod to minimize this problem.
The other mark against the UEG is its interface. The large number of knobs and switches makes it cost prohibitive to make a larger module. As a result, Encore had to use smaller knobs and cram a lot of functions into a tiny space. In doing this, they had to break a lot of established MOTM standards. The resulting interface is not as attractive as it could be, and not as straightforward, either. Fortunately, this doesn’t effect the modules functionality.
Overall the UEG is an excellent module. The build quality seems to be very solid, and it the design only minor problems. It has dozens of uses within a modular system, and it’s a pleasure to use.