Ultravox Custom Mini-Moog

Ultravox Mini-Moog

Overview I came across a picture of the Mini-Moog that was customized by Roy Gwinn for Ultravox and was intrigued by what the changes were for and how they were implemented. The actual Mini-Moog has long since been scrapped, as it had a very hard life touring and then being painted grey. It was in use from 1980 to 1983, until the later songs used Billy Curries bigger collection of synths and Chris increasingly focused on playing bass guitar.

The modifications were aimed at two limitations of using the Mini-Moog live in 1980; reproducing tight bass lines locked to the drums, and the tuning instability. The  modifications were quickly obsoleted by the introduction of MIDI in 1983 and digital synths.

The custom Mini-Moog was a key part of the revised Ultravox band and sound from June 1980 and the Vienna album. It featured in the bass lines of the album and was played by Chris Cross. I cannot be 100% sure about the modifications but I have collated as much information from the Internet as possible. Big thanks to Roy Gwinn for creating these modifications in 1980!

There are three visible modifications to the Minimoog;

• Left Hand Side – Toggle switches, red push button, input jack and LCD display.
• Lower Front – Extra potentiometer and a 7 segment display.
• Env Generators – Toggle switches.

VCO3 Voltage

Early photographs show only two toggle switches on the left hand panel and no jack socket or red button. The displays are Digital Multi Meters that measure voltages and not music values such as tempo (bpm) or pitch (note values).

Trigger Sequencer This was a modification to the Mini-Moog and used to pump out a steady stream of eighth-notes, which could be transposed up the keyboard by Chris. By keying different notes, a bass line was produced with the unwavering perfect tempo of the machine.  This rock solid tempo had a hypnotic effect to it, which was an important part of the new Ultravox sound, which also used early Roland drum machines like the CR-78.

It looks like VCO3 was used as a LFO to drive the trigger sequencer using the external gate input, then switched into the filter and loudness envelope generators by the toggle switches in the Modifier section. The LFO/sequencer was not in sync with the drum machines and Warren simply played along with acoustic drums. Later on the drum machines were sync’d up as the clock source and the control panel further modified. The CR-78 does have a trigger out for this.

The first incarnation has only two toggle switches on the left panel, possibly external CV and Gate on/off. The second incarnation (1983?) has an extra push button, switch and input jack socket, which I presume is for an external clock from a drum machine, with the extra switch and push button controlling the clock in. This setup would have been easier to use on stage with Warren switching on the drum machine and Chris bringing in the clock on the Mini-Moog to create the bass sequence.

VCO1 & 2 Voltage

DDM Readouts There are two DDM displays; the LCD on the left shows the voltage going into VCO3 and therefore the trigger sequencer tempo, and four 7-segment LED displays show the voltage going into VCO1 and VCO2 – with an extra potentiometer (green cap) marked OSCS Find Tune, to the left of the display.

When VCO3 is switched to LFO mode for sequencing, it is disconnected from both master tune, pitch wheel and the keyboard. It is therefore totally independent and not affected by other pitch controls. The extra fine tune control is connected into the Tune CV output which goes to VCO1 and VCO2.

This voltage is monitored by the DDM before the keyboard and pitch wheel CV’s are added. You can see a display of 52, which might be +5.2V! This would be correct as the Tune control varies from 0 to +10V and its usually set mid way.

I wouldn’t be surprised if the 7-segment display predated the LCD display, as tuning would have been a big issue and LCD’s came out later. Early Mini-Moog’s were renowned for temperature instability and even later ones would have struggled in the hot conditions of a live stage. You can see Chris adjusting the tuning and checking the readout at the start of songs, like All Stood Still.

Env Generator Switches These are unmarked toggle switches, which I think switch the gate input on/off for the filter and loudness envelopes, and therefore whether they are driven by the trigger sequencer.

Replicating Today With the advent of MIDI sequences the Ultravox Mini-Moog trigger sequencer is redundant and its really easy to recreate the 1/8th note sequences on a DAW or MIDI sequencer. If you are into old school CV and Gate and have a Behringer Model D, you can patch the on board LFO to the Gate inputs of the VCF and VCA, to recreate the same effect. Unfortunately this is not possible on the Behringer Poly D, as even though there is a 4th VCO which can be set as a LFO it does not have an external output.

A better approach is to use a 8-step trigger sequencer with toggle switches (e.g. Nosie Engineering – Bin Seq), and drive this from a MIDI clock or analog clock. This delivers the driving 8th notes but with skips and rests, which is probably the way I will go.

Pitch instability of VCO’s is still with us on analog synths, but generally they are more stable than the early Mini-Moog’s. So there is not much call for an onboard fine tune pot and a DDM these days, although your DAW can use tuner plugins to get to the same result, or there are euro rack modules that do the same.