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Sequential Prophet-5 & Prophet-10

Polyphonic Synthesizers By Dave Stewart
Published February 2021

Sequential Prophet-5 & Prophet-10

A conquering hero returns to the fray after long years in exile. Does the new Prophet Rev 4 still have the power to take on the world?

Great excitement here at Stewart HQ as a courier drops off an eagerly anticipated package. No reflection on the UPS delivery service, but I’ve been waiting 20 years for this: since reluctantly putting my beloved Prophet‑5 analogue synth out to pasture in 2001 I’d lived in hope of finding a suitable replacement but, despite some promising leads, it never happened. Then out of the blue last summer, an email from the makers: “We are nearly finished with something that I think might interest you. I’ll get back to you soon with details.” Fast forward four months, and Sequential’s new Prophet‑10 Rev 4 analogue synth now occupies pride of place in my music room. The stars have aligned — my trusty musical accomplice is back in the fold, spruced up, fighting fit and ready to rock.

If you’re wondering what all the fuss is about, take a few moments to reflect on this landmark keyboard’s history. The brainchild of US engineer Dave Smith, the Prophet‑5 was the world’s first fully programmable polyphonic synthesizer. Its breakthrough design enabled keyboard players to create their own sounds and play chords to their heart’s content, which had a revolutionary effect on the music of the day. When Smith’s tiny Sequential Circuits company unveiled their new creation in January 1978 it was an instant success: everybody wanted one, Pink Floyd bought eight and Abba ordered 11! Before long Sequential had a backlog of orders stretching far into the future, though the then‑Head of Sales Bob Styles says that Mr Smith (a huge Who fan) made sure Pete Townshend could jump the queue.

With the demand came problems. The SSM chips used in the early units (more on which later) were in short supply and unreliable to boot, and when the first single‑manual Prophet‑10 units (which doubled the Prophet‑5’s polyphony) shipped, they had to be instantly recalled due to tuning problems caused by heat build‑up. Though less severely affected, the early Prophet‑5 Rev 1 and Rev 2 models also suffered from unstable tuning, but happily the rejigged Rev 3 proved more reliable and became a best‑seller until production ceased in 1984. Consequently, most secondhand Prophets on sale nowadays tend to be the Rev 3 vintage.

Meet The New Boss

The new Prophet Rev 4 instruments take over where their predecessors left off, nailing the reliability issues and building on the legacy with a bunch of new features. The Prophet‑5 and Prophet‑10 Rev 4s are physically identical, the only operational differences being that by virtue of its additional voices, the latter takes twice as long to complete its autotune/calibrate cycle and also has a slightly higher maximum power consumption. That said, I’m pleased to report that unlike the original, it doesn’t get hot!

Housed in an all‑steel chassis with a classy black walnut heartwood body and trim matching the look of a vintage Rev 3, the new Prophet uses a five‑octave, semi‑weighted Fatar TP/9S keyboard. Personally I prefer unweighted keys, but those with good pianistic technique will probably enjoy the solid feel and noise‑free action of this keyboard. Pianists will also appreciate the Prophet‑10’s higher polyphony when piling up notes via their sustain pedal, though when playing my old Prophet‑5 I usually found its five notes were sufficient — you just have to cool it with the left‑hand octaves!

The pitch and mod wheels remain in their original, sensible locations to the left of the keyboard (why manufacturers put them elsewhere beats me), while the rear panel includes two welcome innovations: USB connectivity and a headphone output (nominally stereo, though the synth remains as defiantly mono as its ancestor), with headphone level controlled by the master volume knob. There are also connections for MIDI In, Out and Thru, sustain pedal, volume and filter cutoff expression pedals, and unbalanced audio out on a standard quarter‑inch jack. Jack connections are also provided for CV and Gate in and out.

Good news for gigging keyboardists: the new Prophets operate worldwide on voltages between 100 and 240 Volts at 50 to 60 Hz, weigh only 31lbs (14.06kg) and fit comfortably on a conventional keyboard stand. Tuning bugbears appear to be a thing of the past; it’s advisable to use the internal A=440 tone to check the master tuning from time to time, but I found the synth’s 10 voices maintained a solid tuning relationship over a period of days.

The Prophet‑5 and 10 share the same back panel, with both offering a USB port, full‑size MIDI In, Out and Thru ports, and a selection of quarter‑inch sockets for pedal inputs, CV & Gate, headphones and audio output.The Prophet‑5 and 10 share the same back panel, with both offering a USB port, full‑size MIDI In, Out and Thru ports, and a selection of quarter‑inch sockets for pedal inputs, CV & Gate, headphones and audio output.

Oscillators & Waveforms

One of the joys of the original Prophet is its beautifully simple and logical panel layout, which gave users instant access to its sound‑shaping facilities without recourse to hidden sub‑menus. Dave Smith has stuck closely to this layout, enabling Prophet veterans to dive in and immediately start programming.

To the untrained eye the panel looks identical to the old Prophet‑5: a pair of oscillators labelled ‘A’ and ‘B’, each with its own volume control, generate sawtooth and variable‑width pulse waves, while oscillator B has an additional triangle wave and can double as an LFO. Multiple waveforms may be combined to create more complex waves, and white noise (a useful source for drum sounds) is also included. The wonderful ‘sync’ button locks osc A’s wave cycle to osc B, producing that unmistakeable throaty, swept‑harmonic Prophet sound, a must‑have for 1980s keyboard players.

For pitch wobbles, pulses, dubstep ‘wubs’ and shimmers, you can dial up a dedicated LFO with a choice of three independent waveforms. A handy new ‘initial amount’ pot allows you to bake the LFO effect into a patch rather than having to lunge for the mod wheel — this is particularly useful for programming pulse‑width modulation, an essential ingredient of lush analogue string pads.

Filters & Poly Mod

The new Prophets incorporate two switchable four‑pole, resonant low‑pass filters which emulate those used in the Rev 1, 2 and 3 (more details below). The amplifier and filter have independent ADSR envelopes and the latter self‑oscillates at high settings — not, it must be said, with such devastating aural consequences as my old Prophet‑5’s insanely loud filter oscillation, which regularly deafened my long‑suffering bandmates.

Other classic features include an iconic glide effect (great for EDM risers) which now works polyphonically, and a massive‑sounding unison mode which will rattle your chandeliers and dislodge soot from your chimney. That brings us to the Prophet’s secret weapon, ‘Poly Mod’: as well as generating cool robot‑voice sonorities, Poly Mod produces bass and lead sounds that will blow your head off, the sort of iconoclastic, banging, ripping, rampaging synth timbres you might hear on a Prodigy track, but definitely won’t encounter on an André Lieu Christmas album.

Modern synths tend to include dozens of modulation options which sound exciting on paper but often turn out to have negligible musical value. As a long‑time user I can say that the Poly Mod’s two sources and three destinations are capable of creating a huge array of powerful, ear‑grabbing and atmospheric patches. This excellent synthesis tool kept me inspired for years, and I was still discovering new creative angles when my Rev 2 finally bit the dust.

The two instruments share the same all‑metal chassis, both measuring 952 x 416 x 124 mm and weighing just over 14kg.The two instruments share the same all‑metal chassis, both measuring 952 x 416 x 124 mm and weighing just over 14kg.

Patches & Factory Sounds

In bygone days when hapless American music store staff referred to this mysterious new instrument as a ‘sympathiser’, the Prophet had 40 programs. The new Prophet has 400 — 200 are factory programs which can’t be overwritten, the rest are set aside for your user programs. Sequential duplicated the factory set in the user section, giving would‑be programmers a convenient starting point for their edits.

As ever, programs are saved in banks of 40 which are now presented in five groups. When editing a sound, a small red LED dot appears in the display when your tweaked knob or switch setting corresponds to that of the saved program, which is very helpful. Disappointingly, program dumps can only be done via MIDI SysEx; I had hoped to back up programs on a USB memory stick, but though you can transmit MIDI data over USB, you’ll still need a SysEx device or software to store it. To that end, Sequential’s website links you to Soundtower’s powerful Prophet‑5/‑10 Sound Editor for Mac and Windows.

The original 1978 factory sounds are included as programs 511‑558 (nines and zeroes don’t exist in Prophet world). Many sound pretty feeble by modern standards, but you can instantly improve some by turning their oscillator volumes up and shortening the release. Old favourites include the classic ‘Sync i’ (517), the genre‑defining ‘Sync ii’ (532) and the otherworldly space drone of ‘Alien’ (551). Of the new sounds, I liked the cinematic, alien timpani sound of ‘Surdo Taiko’ (156), the mellow twang of ‘Fat Poly Bass’ (216) and the huge majestic swell of ‘Sync Swellpad’ (424). In the SFX department, ‘Under The Ice’ (255) creates an instant 1950s Radiophonic sci‑fi texture, while ‘Kitten’ (252) went down a storm in this cat‑loving household.

Recreating my old Prophet programs was surprisingly quick and easy: orchestral tone trills sounded perfectly in tune (rarely the case with my old Rev 2), my ‘Black Sabbath Bass’ patch was more massive and ear‑shredding than ever, pads sounded suitably warm, lush and expansive, while lead sounds kicked vintage arse. One caveat: there’s no built‑in effects section, so to sweeten the Prophet’s big, raw sound you’ll need to add external effects such as stereo chorus and delay.

The MIDI Pioneer

Dave Smith at Synthplex 2019.Dave Smith at Synthplex 2019.It’s worth remembering that Dave Smith conceived, pioneered and named MIDI in the early 1980s. As a result, you can now play your Korg Kronos workstation from your Sequential synth (and vice versa), use a MIDI control surface to adjust your DAW settings, send a MIDI file of your song to a collaborator on the other side of the planet, and so on ad infinitum. A pretty good invention I’d say, for which our man won a Technical Grammy in 2013. Given that, it’s no surprise that the Prophet Rev 4’s MIDI implementation is spot on.

In addition to standard MIDI control changes (CC1 modulation, CC7 master volume, CC11 expression, CC64 sustain pedal, etc), the front‑panel controls have all been assigned instrument‑specific MIDI controllers, so any changes you make to knobs and switches will be transmitted over MIDI and recorded in your DAW. As a result, you can program filter sweeps, LFO modulation, release on/off, program changes and anything else that takes your fancy. When played over MIDI you can also access the Prophet Rev 4’s full nine‑octave range, from ludicrously low bass judderings to stratospherically high pitches which even a bat might have trouble hearing.

Chips Off The Old Block

Arguments over the respective qualities of the Rev 2 and Rev 3 Prophets boil down to the former’s warmth and subtly organic timbre versus the accuracy, improved reliability and marginally brighter tone of the latter. Some claim the difference is negligible; Dave Smith himself admits that the two models sound different, but added that when he recently compared several Rev 3’s, no two sounded alike!

In an attempt to achieve the best of both worlds, both instruments’ filter types are included in the new Rev 4. You can switch between an SSI 2140 filter designed by Dave Rossum (the modern counterpart of the Rev 1 and Rev 2’s Rossum‑designed SSM 2040) and the original Doug Curtis‑designed CEM 3320 filter used for the Rev 3.

For the oscillators, Smith opted for the original Curtis CEM 3340 VCOs, also used in the Rev 3.

The basic central core of the analogue signal path remains exactly the same, but in a further nod towards Rev 1 and 2 disciples, the maker included a ‘Vintage’ knob which loosens up the tuning, envelopes and amplifiers as you increase its intensity. According to Smith, it’s like having all four Prophet revisions in one box. Though currently comatose my Rev 2 lives on in my recordings, and to my ears the Rev 4, though not 100‑percent identical, does a very decent job of emulating its timbre. Judged on its own merits, the new synth sounds clean, rich and stable, with a big, warm, enveloping and hugely powerful bottom end which will sound immense on a club PA.

Its simple, clear‑minded design makes it the ideal keyboard for learning synth programming, and I’m sure new Prophet owners will have as much creative fun with it as I did.


It’s been a pleasure to revisit the instrument which had a transformative effect on my music‑making back in the day. Its simple, clear‑minded design makes it the ideal keyboard for learning synth programming, and I’m sure new Prophet owners will have as much creative fun with it as I did. In fact, Dave Smith remarked that it’s been very satisfying for him to see the response, not only from those who know the original, but also from younger musicians who had not used a Prophet‑5 before.

Over to Mr Smith: “The project was roughly a year, but it really got intense when we went into lockdown and we all worked from home. I ended up really enjoying the process of going back and relearning the original — it was certainly a great way to get through the initial shock of social isolation. Anyway, it was fun, and it turned out great. It is interesting to look back at this as kind of like bookends, you know, like ‘Prophet‑5 to Prophet‑5...’ I just turned 70, so this is it — this is my birthday present to the world.”

I’m sure the thousands of musicians who play his instruments will join me in wishing this visionary engineer a happy 70th birthday. Put your feet up and have a glass of wine, but don’t retire yet Dave — we’re all looking forward to the Prophet Rev 5!

New Bells & Whistles

To mark the Prophet’s 21st‑century resurrection its inventor added many new features. Velocity and aftertouch can now control the amplifier filter and cutoff, adding great dynamic and expressive potential; a new unison‑mode chord memory feature enables you to play your favourite voicings with one finger, and alternative scale tunings are also available if you want to get experimental or ‘go raga’.

The old synth’s unison last‑note priority (which sometimes caused problems when an accidentally brushed key cut off a held note) can now be switched to low‑note priority. You can also stipulate the number of unison voices and alter their degree of detuning. New global controls include transpose and local control off, which prevents the synth from double‑triggering when played via a DAW MIDI track. There are also enhancements to the pot behaviour and release/sustain function, explained with beautiful clarity in the downloadable user’s guide.

Prophet Rev 4 vs Prophet‑5 Rev 1

I was very keen to compare the Rev 4 against my Rev 1 Prophet‑5, the synth that is perceived by many to be the Holy Grail of Prophets and, when testing the two using simple patches, I was often able to make them sound very similar. There were differences of course. For example, the balance of the waveform levels in oscillator 2 was different, the total level of oscillator 2 is lower on my Rev 1, and the maximum amount by which the filter contour is applied to the cutoff frequency is greater on my Rev 1. Can I say that these differences are true of all Rev 1s? No... and there’s no way to know whether, after innumerable tunings and recalibrations, this is my synth’s original response. After all of this time, I doubt that any two SSM‑based Prophets sound identical.

More complex sounds inevitably revealed other differences but, if I had to distinguish between the characters of the two synths in a single word, I would say that the Rev 1 sounds coarser than the Rev 4. Dave Smith and his team have identified one of the factors that makes vintage Prophets sound big — the variation in the voices — but there are two others: noise and, in particular, distortion in the audio signal path. The Rev 4 is much better behaved in this regard so the Rev 1 can sound more aggressive, especially with the filter wide open. Does this make the vintage synth superior or inferior? I suppose that that depends upon what you’re trying to achieve. And, while even a single oscillator patch on a Rev 1 can sound ‘bigger’ than many dual‑oscillator polysynths, it can also be incredibly unpredictable, to the extent that it can be unusable on a bad day.

But in the real world, these differences are probably irrelevant. That’s because there are few fully operational SSM‑based Prophets left and, 40 years on, there’s no guarantee that you will ever lay your hands on one. When I fired up my Rev 1 to do these tests, it wouldn’t tune accurately and I had to attack its internal trimmers with a screwdriver. While nine of its oscillators could be cajoled into behaving themselves, I found that Osc2 on Voice #2 wouldn’t track correctly, so I had to mute that voice using its VCA trimmer. This makes my Rev 1 (temporarily?) unusable because there’s a hole every time that that voice is selected. So the real question should be, “if you overlook all of its extra features, is the Rev 4 similar enough to replace it?”. I believe that it is. Sure, there’s something special and monstrous about a Rev 1 when it decides to play nicely but, with the Rev 4’s filter set to SSM mode and its vintage knob in the region of 2.5, the two could often be made to sound so similar that I didn’t care about the differences. Were my Rev 1 to die a final, catastrophic death tomorrow, I see no reason why I couldn’t replace it with a Rev 4. Oh yes… and the new one doesn’t have a fan. Yippee! Gordon Reid

Last Voyage Of The Rev 2

While praising the earlier Prophet models’ great sound, many owners will attest to their unreliability. My experience was typical: having acquired a Rev 2 in 1978, I fell in love with it and had a field day creating new programs, but the bloody thing kept going wrong. Even after retrofitting a heatsink it required continual servicing and tuning, and once disgraced itself during a live show by randomly riffling through its 40 presets, underlining the musical truism that electronic elephant calls and sci‑fi SFX are not the ideal accompaniment for a quiet ballad.

Given that embarrassing showstopper, it was clearly an act of folly to risk flying this temperamental keyboard halfway around the world. When I asked Prophet guru Tim Wallhead to service my Rev 2 prior to some Japanese gigs, the blood drained from his face: “You’re not taking that to Tokyo, are you?” “Er, yes”. “I wouldn’t if I were you, it’ll never make it.” My reply echoed the words engraved on the tombstones of countless failed escapologists, deceased daredevil stuntmen and gravity‑stricken tightrope walkers: “Don’t worry, it’ll be all right on the night.”

Amazingly, it was. Against all the odds, after being lugged in and out of vans, chucked into an airplane hold, flown at 35,000 feet, driven 70km from the airport and hauled up six floors into the venue, the Prophet behaved perfectly. After a nervous few moments while it went through its autotune cycle, it emerged refreshed, vibrant, stable and more in tune than I could remember, retained its programs and held its tuning throughout the show and a second gig the next night. I could hardly believe it.

Sadly, as soon as we got back to England it immediately threw a wobbler, and that was pretty much the last hurrah of this unpredictable instrument. The moral of the story is, if you’re considering paying through the nose to get your hands on an original Prophet‑5, think again. Things have moved on: you can now buy a spiffing new Prophet Rev 4 which sounds just as good, stays in tune, offers a wealth of new features and won’t require servicing every 10 minutes. If you decide to ignore this advice, better find a good keyboard tech and arrange a bank loan to cover the inevitable repair bills!

Prophet Rev 4 vs Prophet‑10

The CEM‑based Rev 3.x Prophets were better behaved than the SSM‑based instruments that preceded them, with greater tuning stability, more consistency between voices and less distortion in the signal path. While this was a boon for many players, it led others to conclude that they were less ‘organic’ than their predecessors. (If you equate being out of tune to being organic, this was undoubtedly true.) Consequently, the Rev 4 finds it easier to emulate the various models of Rev 3 than it does the Rev 1 and Rev 2. With the filter switch in the CEM position and the Vintage knob somewhere in the region of ‘3’, the sound and behaviour of the two synths becomes very similar indeed. If you find the sweet spot where the knob adds a bit of natural chorusing without creating audible inconsistencies (too much and the sound becomes too unstable, too little and everything becomes too ‘nice’ to be the vintage synth) I doubt that you could slip a leftover Rizla between some of the sounds produced by a Rev 3 and a Rev 4.

The Rev 3 architecture also formed the basis of the mighty dual‑manual Prophet‑10 which, apart from requiring two burly roadies to lift its Anvil flight case off the truck, and another two to get it out of said case, remains one of the most desirable analogue synths of all time. Clearly, the 10‑voice version of the Rev 4 isn’t physically similar to this, and there are far too many functional differences to compare them meaningfully. For example, the original is bi‑timbral, it has a three‑band EQ, a drone mode, a polyphonic sequencer, individual transpositions of the two manuals, panel controls for the pedal inputs, individual quarter‑inch and XLR outputs, an extra LFO waveform, and no fewer than four keyboard assignment modes that included the ability to layer two Prophet‑5s on a single manual. But choosing the same settings as used to emulate a Rev 3 Prophet‑5, the Rev 4 can sound very similar to a Prophet‑10.

However, there is a more meaningful comparison, albeit not one that I am able to test. Long before the dual‑manual Prophet‑10, the very first Prophet was released in both 5‑voice and 10‑voice versions. Unfortunately, heating issues made the 10‑voice version impractical and almost all were recalled by Sequential Circuits and converted to 5‑voice instruments — the ones that we now call Rev 1 Prophet‑5s. So finally, 42 years later, something akin to the original Prophet‑10 can now be heard by taking a 10‑voice Rev 4, putting it into SSM mode, and then turning the Vintage knob high enough to send players with perfect pitch screaming for the hills. Gordon Reid


  • The new Rev 4 Prophet‑5 and Prophet‑10 synths recreate the original instruments with the utmost authenticity.
  • The new versions add essential modern features such as velocity, aftertouch, USB and a full MIDI spec.
  • You can switch between Rev 1/2 and Rev 3 filters.
  • The instruments look and sound as great as ever, combining the classic Prophet design with rock‑solid tuning.


  • The price.
  • Patch archiving is still done via MIDI SysEx data dumps, rather than a simple save onto a USB stick.


This legendary keyboard created the template and set the standard for hundreds of imitators, few of which sounded as good. Now the Prophet is back, replicating the original classic design while offering a host of new features and vastly improved reliability. Great for lush PWM string pads, brass stabs, screaming lead lines, big EDM pads and risers, banging bass sounds, delicate choir and flutes, vintage organ emulations and sci‑fi effects, the Rev 4 Prophet‑5 and Prophet‑10 have resumed their place at the top table of polyphonic analogue synths.


Prophet‑5 £3299, Prophet‑10 £3999. Prices include VAT.

Prophet-5 $3499, Prophet-10 $4299.