Pro-One close-up

Pro-One demos

Unease: Pro-One Bass Demo.mp3
Two pulse waves with PWM one octave apart.
Tweaked: Envelop Amount, Filter Resonance,
Filter Envelope Attack/Decay/Sustain, LFO Frequency (speed of the PWM).

Unease: Pro-One Sync Demo.mp3
Osc A is synchronized to by Osc B.
Both oscillators with pulse waveforms.
Tweaked: Osc A Frequency, Pulse Width of both oscillators via the modulation matrix, Filter Resonance, Filter Cut-off.

Unease: Pro-One FM Demo.mp3
Two pulse waves. Osc B is modulating both
Osc A Frequency and Filter Cut-off via the modulation matrix. Tweaked: Amount of
modulation of Osc A Freq and Filter Cut-off,
Filter Cut-off, Filter Resonance, Noise Level.

Unease: Don't Go replica.mp3
All sounds made by the Pro-One including the drums, only reverb is added. The lead and the "whrooau" sound is doubled to get really fat.

Unease songs with Pro-One

The Pro-One has been used on the two Unease songs "Absinthe" and "Misled", listen at either or

Pro-One patch sheets

These patches are Unease' interpretations of the ones used by Vince Clarke in the song "Don't Go":

Unease: Don't Go Bass.jpg

Unease: Don't Go Lead.jpg

Unease: Don't Go Arpeggio.jpg

Unease: Don't Go Whrooau.jpg

Mail us and ask for Yazoo's "Only You" patches.

Pro-One Mainboard

Pro-One Mainboard

Pro-One Mainboard

Pro-One Mainboard

Copyright ©1998-2007 Unease.
The images, mp3s and text on these pages may not be used anywhere else without written permission.

Sequential Circuits Pro-One

The Sequential Circuits Pro-One is by many held as one of the most powerful sounding monosynths together with the MiniMoog and the Arp Odyssey. Although most people think the MiniMoog is unrivalled when it comes to deep bass sounds, the Pro-One is more versatile having a small modulation matrix with two busses. With the modulation matrix the filter envelope, oscillator B and/or the LFO can modulate oscillator A/B frequency, oscillator A/B pulse width or filter cut-off. The modulation can be routed either direct or via the modwheel. This may sound complex but is really straightforward to use.

The Pro-One was brought out on the market as a scaled down and cheaper version of the Prophet 5. The build quality is not in league with the Prophet 5, lacking the beautiful woodwork etc of its big brother. Its keyboard is notorious for its bad action and for being in constant need of service. This is much worse with the later versions using the membrane type keyboard. The membrane keyboard was used in the Pro-Ones with serial number over 8500 and seems to be very hard to service. The small membranes used as contacts for every key usually start producing double trigged notes or lost notes when getting old. Most Pro-Ones however (roughly 10 000 were made) have the much better J-wire type keyboard. The J-wire keyboards are pretty common in other synths and are pretty easy to fix when starting to act strange. Another concern with many of the earliest Pro-Ones, serial numbers under 1500, is that the power supply is mounted on the main board. The weight of the power supply can damage the main board if the synth is dropped etc. Many of the early ones were sent back to the factory for a fix and the ones produced later have the power supply mounted on the chassis instead.

When I bought my Pro-One the pots were very noisy from oxide and its keyboard was in pretty bad shape. I opened it up and cleaned the keyboard, fixed the keys so they were at the same height and started turning the bad pots back and forth to remove some oxide. Now it works very well with only some noise from some pots that I don’t use that frequently. The keyboard also works well even though it still feels very plastic and clicky. The amplitude sustain pot is broken off, but it still works.

The sound of the Pro-One can be described as very raw and gritty but still warm. The lead sounds often have a certain brassy quality to it. It’s not as bass heavy as the Waldorf Pulse but capable of producing really deep and solid bass. With some added EQ I think it is in the same league as the Pulse. The oscillators sound very alive and with PWM they are really massive! Comparing it to the Pulse again, it sounds so much more interesting when fully opening up the filter. The oscillators sound more physical and life full than the Pulse’s DCO:s. The filter can self-oscillate and produce interesting seagull like sounds when on the edge. The envelopes are well known for being extremely fast and snappy, which makes the Pro-One ideal for percussive sounds.

Perhaps the most famous user of the Pro-One is Vince Clark. He used it on Depeche Mode’s first album “Speak and Spell” (1981), but it was on the two album with Yazoo (1982-83) he really got the most out of it. In particularly the first album “Upstairs at Eric’s” the Pro-One dominates heavily with several songs solely made with the Pro-One. At least the first single “Only You” is well known to be an “all Pro-One song” since Vince published the patches in the Electronics and Music Maker magazine. In fact you can replicate most of the leads and bass sounds from this album with your Pro-One. Listen to the short MP3 demo where I have copied the sounds from the other single “Don’t Go”. On this page you will also find the patches I have used. It should be mentioned that the drums probably were made on another system [ARP 2600], other than that it is an all Pro-One song. You may judge for your self.

Other Pro-One artist are Nitzer Ebb, Bronski Beat, Front Line Assembly, Tangerine Dream and Die Krupps.

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