This blog is about somewhat of a legendary synth that has still not been recognised as such.

Some know how significant this instrument has been, but somehow this has not been widely professed.

The Prophet-600 is known, just not as much desired as a Juno-60 or Polysix, which I will also mention a lot in this blog.

Standing in the huge shadow of its older sibling, the mighty Prophet-5, the P600 had a lot to live up to.

It did in many ways, but it also fell short in some areas making people second guess it.

Timing in the 80’s was paramount and the P600 seemed to touch on just a hundredth of a second too late in the race for market dominance.


The purpose of these blogs is to bring an insight into how instruments were received and experienced at the time of release.

We have a lot more access to detailed information now, but back then information was sparse.

Over the years perception can get distorted, so I am going to try and capture the zeitgeist of a time that I was blessed enough to be a part of. 



The reference to a race is no exaggeration, as that’s exactly what was happening in 1982/1983.

It wasn’t like a marathon, more like the 100-metres sprint, where everything happened so quickly, you had to come out of the starting blocks as quickly as you could as a manufacturer.

Sequential Circuits were ready to unleash their fastest sprinter, after their massive success with the Prophet-5, not realising that the other sprinters in the race had the advantage of being even more lean and light-weight.

High expectations and an unfavourable financial climate put the P600 in a more heavy weight position.

To make matters worse, this all happened just before the arrival of another testosterone infused athlete, the Yamaha DX-7.

Japanese companies Korg and Roland both had already set the pace, releasing new Poly synths that would cause a major ripple.

The Polysix and Juno-60 were both exceptionally low priced, giving the American and European manufacturers a run for their money.

This meant that on the big stage (Olympics) each company had to showcase their best athletes to try and outdo Korg and Roland.

The Olympics of innovation was the NAMM show in the US at the beginning of 1983.

Even Korg and Roland themselves were aware that they had to outdo even themselves to avoid embarrassment.

The result was an eventful Olympics, with many highlights.

There is always the main highlight though, the one we all remember that was on everyone’s lips.

The DX-7 was the Ben Johnson of synths, amazing athletic features, an explosive start and then scorned by many for cheating the common consensus.

In terms of synthesis, the DX-7 broke all common consensuses, from the no-knobs controls, to digital FM sound generation and looks, the DX was a completely new and different concept.

In that 100-metre final, the P600 was amongst the last to finish, thus no one really remembering it.

Like the runners that ended last in that important 100-metre sprint, it doesn’t mean they were bad sprinters.

The fact that they made it to the final is enough proof that they had all the qualities of a top sprinter.


Synth Bombardement

Each beginning of the year we experience another surge of new products, from new analogs to software, virtual synths to modular stuff.

It’s hard to keep up and just when you think you’ve seen every product video, there’s still a few more you missed.

Before 1983 a few synths a year was all we got, but 1983 spawned an unusual number of new synths.

Here’s a short list of the synths that were released.

  • Prophet-600
  • Roland Jupiter-6
  • Roland JX-3P
  • Korg Poly-61
  • Siel Opera-6
  • Kawai SX-210
  • Yamaha DX-1
  • Yamaha DX-7 
  • Yamaha DX-9
  • Oberheim OB-8
  • Moog SL-8


The Japanese companies were clearly starting to take over the market with much cheaper synths.

Even though the Americans offered cheaper synths as well, they were still almost double the price of their Japanese counterparts.

The P600 was almost half the price of the P5, but still almost twice as expensive as the Poly-61.

The Moog SL-8 never even made it into production.

It seemed difficult for the American companies to break the low end price barrier and in the following few years this would have catastrophic concequences.


Another important factor was supply.

We can now be pretty much sure that a product will ship soon after its announced, but in 1983 this was not the case.

Manufacturing took much longer than anticipated and technology still being in its infancy, problems needed to be ironed out first. 

Products were announced far before they were actually available.

A new phenomenon was arising, “The Waiting List”.

There were suddenly waiting lists at dealers, so you had to be lucky that your dealer would get in a good amount of stock.

A lot of people had been trying to save up for one of the big polies, but were suddenly in an instant able to purchase something for a lot less.


I remember going to a Korg demo night in the city of Utrecht in 1982 with my dad, who was in the market for a polysynth.

I was 14-years of age and completely imbued with synthesizers.

At the ‘Jaarbeurs building’ a small convention room was set up to demo the Crumar Status and Trilogy, Synton modular system and the star of the show, which everyone had rocked up for, the Korg Polysix.

After the demo everyone gathered around the Polysix.

We heard one guy say to the Korg rep;  “I brought 4200-guilders in cash, can I buy this unit?”

As that unit happened to be the only unit available for demonstration purposes, the person got swiftly disillusioned by a firm “NO”.

That person’s attempt would sound outrageous in this day and age, but this was how desperate people were in 1982, as there was nothing on offer at that price point with those features.

When 1-year later the floodgates opened people had become a lot less desperate, but the next problem they had to face was making a choice.

The P600 and JP6 were still expensive, both hovering around the 8000-guilder mark.

That still seems like a lot of money, but considering that the Prophet-5 and Jupiter-8 were around the 15000-guilder mark, the P600 and JP6 were still a very attractive proposition.

A Prophet-600 ad in the Dutch Music Maker magazine even stated “A synth under 10K which sounds like a synth over 10K”, indicates how fortunate we were at that stage to be able to buy something that good for almost half the price.

Still, these amounts of money could also buy you a car.


So I keep mentioning prices in Dutch Guilders.

This is because that’s all I remember, plus I still have kept all the Music Maker magazines with the ads in them.

How does the Guilder translate to Euros or USD?

The P600 cost 7700-guilders in 1983.

With today’s purchasing power this equates to 14,000-guilders.

That's equivalent to 6500-Euros or 7600-USD.

In 2018 that would buy you two extremely powerful polysynths, such as the DSI Prophet-6 and OB-6.

It can buy you seven Deepmind-12’s.

To say that we are spoiled for choice these days is a huge understatement.


Why were prices so high back then?

There have been many factors that contributed to these steep prices.

Labour, Import duties, trade agreements between countries, parts tariffs (such as we are experiencing now) and probably most importantly unfavourable currency exchange-rates, would have all amounted to these crazy prices.

You also couldn’t shop around in neighbouring countries, as back in 1983 each country had border-control and cars were frequently checked for goods at border crossings.

Getting a P600 in Germany for a little less was hardly worth taking the risk.

Still, we felt we were spoiled for choice, which seems hard to believe.


My dad was one of the few people in the Netherlands to go for the P600.

Most of his fellow keyboard colleagues were going for a Juno-60, Polysix or Poly-61.

My dad chose for the P600 because he had been playing a Minimoog for many years and the sound of the Prophet was closest to that of the Moog.

He also had a mate who was one of a handful of people who had a Prophet-5 and my dad had played his P5 a couple of times.

Kick Music in Hilversum would make sure my dad would get the first P600 in Europe, as the Sequential Circuits distribution office was in Mijdrecht, close to Amsterdam. 

1-year later he got a DX-7, replacing his Rhodes Suitcase piano.

He used these two keyboards till the late 80’s.


P600 vs P5

How does the P600 compare to the P5?

One can say that after the Minimoog, the Prophet-5 was the next biggest innovative breakthrough in synthesizer history.

A polyphonic synth with 48 recallable memories, compact and rich sounding.

It met all the criteria for the modern keyboard player.

From 1978 all eyes were on the P5.

Even the Oberheim OBX was heavily influenced by the Prophet and suddenly every synth that followed bore some resemblance to the Prophet-5.

A new norm was set, but as mentioned before, one major barrier stood in between many musicians and the P5: its price.

In order to compete in the price war cutting costs meant cutting corners for Sequential Circuits.

Korg and Roland cleverly replaced one oscillator by a sub-oscillator and adding a chorus effect, creating the illusion of a second oscillator.

The drawback was that it limited sonic range, as a second oscillator could use a different waveform, be tuned differently, be synced or modulated.

Another major cost-cutting choice was to use a single envelope generator for both the VCF and VCA (Filter & Amplifier).

For Sequential Circuits omission of the 2nd oscillator and envelope generator was going to drastically compromise the Prophet sound.

Even though the cost of components had come down between 1978 and 1982, it was inevitable to design a slimmed down Prophet.

Interestingly Sequential Circuits had also been working on an even bigger Prophet, the T8, which also arrived very late to the party.



I’ll try to outline the major differences and am sure there will be more worth mentioning, but these differences were most relevant at the time..

  1. The most obvious difference is that the P600 has 6-voices compared the the 5-voices on the Prophet-5. This will particularly become apparent when in Unison mode, where the P600 sounds bigger due to its extra 2-oscillators.
  2. A really cool feature on the P600 is Unison Chord-Memory, whereby you play a chord and switch to Unison mode. The chord can then be played across all the keys.
  3. The P600 offered 100-memory locations, compared to the 48 on the P5. These were however expanded on the last P5 Revision 3.3 to 120. There were 3rd party expansions available as well for earlier revisions.
  4. The Noise-Generator was omitted on the P600, which has always been one of its main foibles.
  5. The Potentiometers on the P600 were 4-bit, which means that you can never really accurately dial in a setting and especially on the Filter Frequency dial this was very noticeable, often referred to as stepping, as on a full rotation there's only 16 steps.
  6. The P600 featured a Sequencer and Arpeggiator. The Sequencer was a scratchpad type affair, where there was no fixed end-point or quantisation of notes. This was only handy for editing and auditioning sounds hands-free. The Arpeggiator had the Up, Down, Up & Down and Latch feature, where the notes would play in the order they were played.
  7. The P5 had a volume knob for each oscillator, whereas the P600 had a ballans knob. This may not be a big deal, but it caused each patch to have different output levels.
  8. Possibly the biggest cost-cut was to make physical changes to the P600. Still flanked by vintage style wooden end-cheeks, the P600 featured a considerable less amount of woodwork, making it much smaller in size. Apart from the potentiometers being inferior, the knobs themselves were also less flashy, with the shiny chrome edges absented. 
  9. Touch-membranes were the fashion in 1982. Perhaps borrowed from the Moog Source. The touch membranes on the P600 are a hit and miss and are not as responsive as the switch-buttons on the P5. It quite often happens that you punch in a number twice, so instead of selecting 19, it could double trigger the 1 selecting patch 11.
  10. Where the P5 used switch-buttons for every function, the P600 used serrated sliding-switches, which move very coarsely. The other downside of these switches is that it doesn’t show you which position it’s in when selecting another preset. The P5 has LED’s on the switches indicating the ON/OFF status. This made it easy to see if i.e. Keyboard tracking was on or not.
  11. A really cool improvement on the P600, was that the LFO could be applied without using the Modulation wheel.
  12. The keybed on both instruments were possibly their weakest feature. The P5 and P600 use different keybeds. The P600 keybed has more clicks & clacks. The P5 keybed plays more smooth and is less noisy, but is a nightmare to service. 
  13. Sound difference was of course unavoidable due to the cost-cutting measures. However, the oscillator, filter and envelope chips were the same as used on the P5. Because the circuitry was redesigned, the signal path was also different, but the P600 astonishingly sounds very much like the P5. The weight of the sound is pretty much the same, but the envelopes on the P600 are extremely sluggish, which was due to the 4-bit pots.
  14. The last new feature on the P600 needs its own dedicated section.



Now we have arrived at an important junction in synthesizer history, one that the P600 played an important role in.

Every single keyboard instrument has one feature that is entirely unique to that instrument, but one new feature on the P600 has changed the entire course of music technology: the Musical-Instrument-Digital-Interface.

I am not going to explain MIDI in full detail here, as I want to stay focussed on the P600, but for those who wonder how MIDI came about, here’s a brief synopsis.


Before 1982 each manufacturer was using their own interfaces for their devices to interact with each other.

Oberheim was using an interface system that allowed their DSX sequencer to play back sounds on the OBXa synthesizer. Their DMX drummachine would then run in sync to the DSX sequencer and you’d therefor have a music production system, which was limited only to Oberheim products. 

Using the DSX sequencer with a Prophet-5 would require major modifications.

Roland had their DCB system en Moog was also doing their own thing.

Dave Smith of Sequential Circuits initiated the idea of designing a universal communications interface that would become a world wide standard.

He discussed his idea with Roland manager Ikutaro Kakehashi, already having engineered an idea for what was going to become MIDI, at the NAMM show of 1982.

In meetings with other manufacturers there was much resistance, but with the biggest instrument manufacturer in the world Yamaha backing the idea, simplicity and low cost implementation undeniably lead to a standardisation in 1983.

With Smith and Kakehashi firmly believing in this new standard, both companies introduced MIDI on their new products at the winter NAMM show in 1983.

The Prophet-600 and Jupiter-6 were the first ever MIDI devices to shake hands via the 5-pin DIN plug.

As a side note, this MIDI standard remained unchanged for the following 35-years and is still going strong.


Improvements to the P600

Even during the analog revival of the 1990’s, the P600 was a small dot on people’s radar.

This kept its price down and it still really hasn’t risen much to this day.

Because of that people started thinking of ways to make the synth more appealing.

One of the P600’s weakest qualities were the sloppy envelopes due to the low resolution of the parameters.

In order to make the P600 sound closer to the snappy sound of the P5, the CPU had to be redesigned.

The GliGli CPU upgrade is such redesigned processor, which replaces the original Z80 processor.

This upgrade adds many additional features, but most importantly gives the P600 a much tighter sound.

Resolution for the pots have gone from 4-bit to 7-bit, which changes the stepping from 16 variations to 128.

The LFO functions have been expanded and it also features Unison Detune and a Mix Overdrive.

The synth also becomes fully MIDI controllable via CC.



Another upgrade to the P600 is the Das Musikding Pan-Mod made by Peter Kliegelhöfer.

This extremely affordable mod gives the P600 pan-pots for each voice board, the same way the Oberheim OB-8 and OBXa can pan their voices.

A small cut-out in the side panel is required to install the pan-pots.

The installation however, is not as straight forward as that of the GliGli upgrade and requires more electronics knowledge.

A friend of mine has recently installed this mod himself and he made a really cool video demonstrating how wide it can sound.


Final Words

It is safe to say that the Prophet-600 is still one of synthesizer history’s best kept secrets.

For the prices that they are going for you will absolutely get an instrument (like they said in the ad) that sounds like a 10k synth.

Sonically it has the same heft as the bigger polysynths, like the OB-8, P5 and JP8.

With the GliGli and Pan-Mod upgrades, you will have a synth that in many ways even succeeds the aforementioned.

Even without these mods the P600 sounds great and very unique.

It would be hard to mention another vintage analog synth that sounds this good at this price.

It’s 6-voice, 12-oscillators, has MIDI and that classic Prophet sound, what more could you wish for?


Is finding a 2nd hand P600 easy?

Well, it depends on what part of the world you’re in.

The P600 was not a major commercial success, due to its price, the reputation it had to live up to and the time it was released in.

Although released just before the DX-7, it arrived a little too late, as people were already aware of the DX-7, holding off on the purchase of any synth.

The cheaper polysynths, like the Juno-60 and Polysix sold well because the DX-7 was still a bit of a leap up in price and no one yet knew what to expect from the DX.

Another thing that happened soon after the P600 arrived, was that the price of the Prophet-5 came down.

There was therefor a very short time period in which the P600 grew enough appeal.

As I mentioned at the start, timing was everything at that particular time.

No one had really anticipated the success of the DX-7, which pretty much blew every synth out of the water.

Expensive synths that were released well before the DX-7 still managed to fill a void, but for the big models that arrived in 1982, such as the Memorymoog, Rhodes Chroma and Yamaha CS-70M, a run of success was short lived.

With the P600 even arriving a little later onto the scene, one can imagine how difficult it would have been to market the instrument and for buyers to spend that much when options were aplenty.

Fortunately, for the people that discover the P600’s brilliance at a much more affordable price today, the P600 can be one of the best purchases one could ever make.


Important things to watch out for are any tears in the membrane-panel, scratchy pots and an empty memory battery.

The keybed is another thing that might put you off, as it’s possibly one of the noisiest ever made.

All together, the Prophet-600 deserves more credit and recognition than it gets.



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Add comment


Lars Erlandsson
a year ago

Great read! A note:The potentiometers on the P5 are only 7 bit (128 values). This was pretty common and it also is the same resolution as midi cc has. I'm currently working on a keyboard replacement kit for the Prophet-600 after doing the same for the Pro-One (which has a REALLY bad keyboard). I also sell knob caps to make the Pro-One/Prophet-600 knobs look like the Prophet-5 knobs :) More at

Gee Vee
a year ago

Thank you Lars for the info!!!
All the best with the mods, sounds exciting.

Peter Kliegelhöfer
a year ago

Great article, I can only echo that the P600 is a fantastic sounding synthesizer!
Also interesting comments from Lars, will watch out for his mods. My Pro-One is a J-type with a slightly more reliable keyboard but nonetheless good to see there shall be improvements, same for the P600. Please note, in the meantime there is also a stereo mod kit for the Korg Polysix available from Das Musikding.