Prophet 5 Under the Hood w/ Rob Rosen-Clip

We move on to the Prophet 5 which is the first fully programable synthesizer created by Dave Smith by instituting the Z80 chip. Rob Rosen from Rosen Sound gives us a close look at his REV 1 instrument signed by Dave Smith (that was most likely made in his garage). Dave Smith was the first to create a micro controller based instrument that essentially replaced a lot of the complexity in the CS-80. We’ll see the innovative part of the Prophet 5 where the software lives and learn how it controls and interfaces with the sound producing components such as keyboard scanning, voice assigning and sound parameters. We’ll see an early DAC that converts digital into analog and discover temperature compensating resistors. Ribbon cables replace much of the miles of wiring in the CS-80. We isolate on the Oscillator envelope chips and Rob compares the sound of the REV 1, REV 2 and REV 3 versions. We view the keyboard mechanism with J-wires, a bus bar, and how voices are assigned via a myriad of computerized decision making options. Rob and I agree that by understanding the way things work on the inside, it can affect the way we play the instrument.
00:00 Prophet 5 History
01:00 Introduction to Prophet 5 Rev 1
02:43 Dave Smith Innovations
03:36 Inside the Prophet 5
08:52 Rev1 vs Rev2 vs Rev3
09:50 Z80 Microprocessor and signal path
12:11 The Keyboard and Computer Calculations
15:23 Why understand how it works?
17:10 From Analog to AI
Follow Rob @rosen_sound on instagram
Anthony's musical touch as both composer and performer is connected with some of the most influential creative minds over the last 40 years. He’s composed and conducted original orchestral scores for over 80 feature films including Young Guns, Internal Affairs, The Man From Elysian Fields, 15 Minutes and Planes, Trains & Automobiles, been commissioned by the Los Angeles Philharmonic for his symphonic work "In the Family Way", written over one thousand TV commercials in a myriad of musical styles, co-founded Levels Audio Post (LA's premiere post production facility) and performed and arranged on big-box-office films and influential hit records such as Michael Jackson's Thriller.
His extensive work as a young arranger, orchestrator and performer for Quincy Jones, Jack Nitzsche, Lamont Dozier, Arthur Rubenstein and Giorgio Moroder was vital in launching his own career. His early years pioneering modular analog synthesizers along with his wide-ranging music scholarship positioned Anthony at the center of the music technology revolution. He attended the University of Southern California School of Music as a piano and composition major.
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[@ozhalljr]

Dave Smith was the man, there's no question about it. Not to be forgotten in the design of the Prophet are Dave Rossum and Scott Wedge of E-mu. They were design consultants to Sequential Circuits for the Prophet 5. They received significant royalties on the P5 Revs 1 and 2. The SSM synth chips in the Rev 1 and 2 were designed in consultation with E-mu. The Emu digital scanning polyphonic keyboard (designed by Scott Wedge for the eMu modular) was the basis for the P5 polyphonic keyboard.

[@b00ts4ndc4ts]

I get the feeling from Rob that he is a great person to have as a friend. When he said ' I wouldn't say one is better than the other, just different.' What a beautiful soul.

[@synthman2000]

I worshiped the Prophet-5 Rev 3 as a kid in 1980 (12 yrs old). Loved this! Another master class under my belt.

[@jimlemons9231]

Awesome! Cool Rob mentioned Yellow Magic Orchestra, I love those guys! How cool to hear all the signal paths and processing explained by Rob too!! Great stuff Anthony!

[@funkycochise]

Lucky days to be able to watch such kind of amazing contents. Knowing all the background behind the different revisions of such an iconic synth leaves me speechless. Anthony and Rob work perfectly together. Technical and Artistical points of view demonstrates why theses instruments are so fascinating and has some kind of magic in them. Keep going !

[@WoodyBReal]

Prophet 5 by Dave Smith- very cool!

[@b00ts4ndc4ts]

Like the fact that he plays them and doesn't keep them locked away.

[@DevanSabaratnam]

Watching all my favourite bands on TV in the early 80's, the Prophet 5 was always standing out on stage, leading me to always wanting one... I still hope to one day get the Prophet 6. Thanks for this breakdown.

[@b00ts4ndc4ts]

Korg or Behringer make good synths for a person who needs scratch an itch with a wallet that's a bit on the light side. Korgs 800 can be picked up for under 500 buck on reverb for a good example.

[@DevanSabaratnam]

@@b00ts4ndc4ts Thanks - I may start with a more budget synth first before moving up to a Prophet 5/6. I need to learn the basic properly.

[@b00ts4ndc4ts]

@@DevanSabaratnam I will warn you now it can get addictive. I started using VST's first but getting hands on with hardware is so much easier. All the best mate.

[@DevanSabaratnam]

@@b00ts4ndc4ts Haha, Thanks! I did get the Arturia Prophet 5 VST and have been playing that on my Arturia keyboard, which lets me use the sliders and dials on the keyboard itself to adjust the VST parameters - certainly a big difference using actual tactile controls instead of a mouse, and I am really looking forward to my first real synth where I can do that for real.

[@b00ts4ndc4ts]

@@DevanSabaratnam Arturia's mini V and their Jupiter 8 are both really good too

[@aerickmccullough350]

Really love this! Rev 4 Prophet 10 user here. (rev 4 Prophet 5, 10 voice version)

[@MusicoElectronico]

A masterpiece of electronic design! Love your channel, keep going!!! 🎶 🎵 ❤️

[@CallousCoder]

Well it’s not a masterpiece of engineering. It’s a very creative insight, for sure. The execution of the engineering is home brewn at best. But that’s usually the case with innovators, they think outside of the box and basically prototype a working solution and others perfect the engineering. It’s easier to perfect someone else’s design than to come up with a design. But when I fixed one for a client I was amazed that a power supply like that actually would be allowed to be made. Same BTW with the AppleII, it’s like in America they have very lacks standards to mains power supplies. The only thing worse I found was 2 years ago (on this channel) a DDR chess computer I fixed. Only when I assembled it again, I read the print: “Netzzecker ziehen bevor offenen” aka pull the plug before opening 🤣I was like: “yeah luckily I always do that out of habit, but this could’ve killed you otherwise 😂” That actually also ran a Z80 but then a stolen clone.

[@johnnybegood2693]

cool closing comment - the individuality of each "dancer" dancing together is what makes it appealing to us (humans ;) 👍

[@falangistavaleroso9689]

I got yesterday a SCI Prophet 2002+ sampler from 1985 ( I got 2 in the 90´s). It shocked me for good that the PSU is magnetically shielded. Dave Smith was a genious, perhaps was to avoid the magnetical radiation deleting the diskettes. I got a friend with deep EHS electrosensibility who can´t stand being close to microwaves or magnetical radiation and I borrowed his measurer. I got more recent samplers as E-mu 6400 turbo that are not shielded, either any Ensoniq is. My Akai S3200 is also shielded. I never had any John Carpenter Prophet 5 but I love my Pro one and the Prophet VS. Rest in peace Dave.

[@Goettel]

All the love for old gear and its preservation is amazing and so is all the love that goes into the new gear, hard- or software. Best time for synths in my 40 years using them, use what you have.

[@Twobarpsi]

One of my top 2 synthesizers ever!

[@MattWhitehead80]

This is really great. I opened my REV3 last weekend after the volume on my P5 disappeared. I’d never actually seen the insides before. Nice to get an idea of how it works. The downside of these old machines is they do occasionally need servicing.

[@dr.gregoryf.maassen2637]

Very nice video. It is amazing what we can take for granted these days with computers and VSTs. Thanks for sharing.

[@anotheryoutube4635]

Basically like going from computers that took up an entire room to the IBM PC, amazing.

[@jacobbrashears]

I have to say, one of the biggest differences between this synthesizer and a modern analog polysynth... the number of green rework jumpers on that IC. In 2023, everybody has stuff like that on our prototypes. But in 1977, apparently Sequential did that on the production line (for at least 14 units)! I think that was much more common in the 1970s, 1980s, 1990s. Today, chips are a little smaller, so rework is a little slower, so it makes more sense to just spin the artwork.

[@foreverlearning7560]

In the late 70s, small business pcb were laid out by hand putting tape on clear polyester then photo reduced 4x to make the exposure masks. No computer aided support. PCB revs were costly, had long lead time and usually required you to permanently modify the previous version. So, you hand modified production boards to validate the design, burn down inventory and keep production running.

[@baddriddimworkshop]

Two books to cite here: "Musical Applications of Microprocessors" by Hal Chamberlain, and "CMOS Cookbook" by Don Lancaster... reedit: two books that allowed tom oberheim or dave smith too start using ssm chips, being later replaced by more "factory biased" and stable curtis chips, and achieve multiple voicing, and then be able to save voltage or switch settings. And yes "says a lot"; designing gear and reparing it is not the same task and often doesnt require the same skills and/or knowledge... love the channel btw.

[@globalsquirrel]

Thank you very much for this! Wondered about the inner workings of this synth for years so now I know. Keep up the great work 👍

[@brmbkl]

Got off work, loaded up the playlist I saved earlier. Watched this with a good coffee and a Vienna pastry. You made my afternoon. Your channel is unique, because of who you are. Just discoverd you a month ago, and already the favorite channel on my watchlist. This is ultimate content, two extremely talented people in their field with zero ego, shooting the breeze and detailing the history of our little niche industry, but make it look like they're just hanging out like two neighbors dropping in on each other. The vibes are off the charts. Please keep going.

[@OtherMike5000]

Thank you for doing this.

[@preservedjams4109]

Loving these videos

[@FPSBird]

I absolutely love these videos exploring the inside of a synth

[@bobsmith3790]

Gee..that was a great video. I learn something new every time I watch one of your videos. This one was fascinating! Thanks to you both for sharing something so special.

[@nebuladus7850]

This Fantastic 🎶🙏✨️✨️✨️✨️✨️

[@jimbotron70]

Fantastic gear.

[@christopherhammell9904]

Love these videos. You must stop releasing these during the work day. 😂 I’m getting nothing done, twenty minutes at a time.

[@Heavy_Distortion]

Oh the tweaky J-wire! My minimoog had one. Before sealed switches. Reissue minimoog has "rock and roll" tuning randomize feature. haha!

[@Jinji11]

Love this:)

[@DannyLHarle]

amazing channel

[@nobodynoone2500]

Great video! Love these deep dives. Wont be as popular as the casio duck bass, but appreciate these a lot!

[@clout123]

I learned so much from this video! It's great to be shown inside and understand how it works. (And outside, as in your other videos.) Especially buy a couple of guys who really love what they're doing.

[@KingMJForeverAndEver]

💛💛💛

[@CallousCoder]

Yeah I agree with him. Analogue or mechanical instruments’ charm comes from being a few cents off and in affect being alive and changing - so much so that a few weeks back after a hot summer my guitar strings choked on the 2nd fret, took me playing two songs and wondering why I had to play it differently to realize that open strings didn’t ring out any more 😂 It gives it that innate modulation and the noise and hiss brings something too. I notice and hear when I play mechanical instruments what my mood and physical being is. When up strung up it sounds more aggressive the attack is harder. When I’m worn out or mellow everything is lighter and more controlled and you hear it too (or at least I think I do). It makes it more organic. And we can model this analogue imperfect on digital technology now to a T but it is ironic that in the 80s we went for digital to get perfection and now the most difficult part in DSP programming is getting that organic imperfection. Which sort of beats the purpose of digital in a sense 😂 But at least we don’t have hellishly out of tune oscillators anymore these days. In the 80s some synths were worse than Gibson Les Pauls when it came to staying in tune, and that’s saying something. 😂

[@CallousCoder]

I had the fortune to fix one 4 years ago. The guy asked me how much does it cost. I said I only charge parts if it works and you’ll let me use it for a week. He agreed and I got to play it for a whole week. And I was amazed how similar my prophet8 actually sounded to the 5 except the 5 felt it had more fundamentals, really droning those low frequencies. But that was indeed a Rev3 looked very different. And in his case the only thing that was wrong was a regulator in the power supply. But that power supply was terribly designed. These days it wouldn’t be allowed on the market in Europe like that. Luckily back then there were no CE certifications otherwise we’d missed out of it. And the Z80 (MSX TRS80, Sinclair) was basically the standard CPU together with the 6502 (Apple C64)

[@Sashabooboo]

2nd time watching this. So much information. I consider a Prophet , including the Prophet Rev 2-16, an analog polysynth but I keep hearing chatter because of the digital aspects. The CS-80 video really made it clear once the guts are compared. I suppose all that matters is how it sounds. (I'm trying to justify buying a Behringer 800🤣🤣

[@Gerald_Daniel]

I almost had a Prophet-5 but it got damaged during delivery. Though the previous owner was the "delivery service", that Prophet still hasn't tolerated its vertikal journey in its case from Vienna to southern Austria. Some parts inside got lose & VCO A turned silent. Luckiy I was refunded. Being still curious: Prophet-5 got replaced by creamware/soniccore PRO-12 ASB (beautiful desktop VA with wooden panel & an authentic Prophet-5 UI). Though it's soundwise not as authentic as Roland's Aira series, PRO-12 at least has 12 strong voices, Velocity and an always tuning stable Poly Mod. The latter is what it makes special & leads to unique, organic sounds, playable across the whole kb not possible with Prophet-5.

[@Andybaby]

If you can't make the music you want with that collection of synths, it's not the synths' fault.

[@analogsynthaficionado6027]

Do not overlook the fact that if Dave Rossum at EMU Systems had not designed and licensed the parts that allowed for memory recall, and the voice, filter, and amplifier chips, companies like Sequential Circuits, Oberheim Electronics, and others would not have produced the products that they did. Dave Rossum and EMU Systems have often been overshadowed in the industry when it was them who helped start it all. Dave Smith and Sequential may have come up with some great gear, but Dave Smith's business tactics were not ideal and often morally bereft. Dave Rossum can attest to that.

[@orionvassi]

Is that the main keyboard used for the California G funk sound? Too $hort, Ant Banks, Mac Dre, etc. Thought is was some kind of Dave Smith product.

[@RaquelFoster]

I think the engineering of scanning the keyboard (licensed from the E-mu guys) was the real foundation of MIDI. Because that was half the work. You've basically got a MIDI message going to the Z80. But DCB on the Jupiter-8 ... that was an actual MIDI message, so maybe it was all Roland LOL.

[@Station2Station-du2gh]

PLAY IT! Just sweep the cutoff while arpeggiating a Cm.

[@psy0rz]

Awesome video! Are those EPROMs ok without protection sticker?

[@kgbinfo]

The wood on this one looks a lot different from the later revisions too. Is it a different type of wood, or is it just the pattern of this specific one?

[@analogsynthaficionado6027]

Early Prophets used KOA wood. Later models were made of Walnut.

[@iannieman]

The Oberheim OB1 allowed you to save patches …

[@TF242]

AI can totally accomplish where your thoughts were Anthony. I think Rob misunderstood the question. AI would be able to help with the imperfections, aka mimic them not cure them. :)

[@nobodynoone2500]

Sometimes it's better to follow your ears. You try playing by circuit, you stop making music for people with ears. The tech is to inform your selection more than your use. I still love my old analog synths, but I will go for whatever makes the sound I am wanting. Amazing how often something like a juno 6/60/106 is just-right.

[@justinb9387]

looks simple compared to the cs80

[@martyjones8016]

I dont know about you guys but I could never keep mine in tune, took it in many times....sucked..

[@RayyMusik]

Call me a heretic - but the Rev 4 is a much better synth across the board.

[@Goettel]

Here's hoping as much great music gets made with it as the earlier revs.

[@chizmo7]

I had two. A Rev 3 and later a Rev 3.2. I never really liked either one. The sound was decent but the synth itself was poorly constructed IMO. The Pratt Read keyboard was sloppy and noisy and the gold J-wires broke quite often. I eventually bought an OB8 and never looked back. I still have it. I do thank Dave Smith for changing the synth world. His contributions to the analog world is immeasurable.