ARP Odyssey

[ScreenSlave]

I should say first that this is nearly finished - it is in a state that can be shared and I invite comments and contributions to help with the last few bits (details below).

I’ve never attempted anything like this before. If I’d known what was going to be involved I may never have started it, but I’m glad I did - I’ve learned so much during this project.

TBH I started out by recreating the main board with PatchMaster and that was going to be it. What can I say - I’m a graphics guy so recreating the look should have been enough. Then a little voice kept whispering - how hard can it be? It’s just a few faders and switches after all.

I did a deep dive into the User Manuals, signal flow diagrams and videos that explained what all the controls do. There’s a series of eight videos by Marc Doty which was particularly helpful (starting with no2 because the first one is just an introduction really).

ARP ODYSSEY - Marc Doty Inside Look Part 2: Oscillator Functions (1 of 2)

I have no illusions that this will sound exactly like an ARP Odyssey (VCO choices were limited due to the frequency range and the necessity for Sync), but it will be close and it should work like an ARP Odyssey.

A lot of the faders have min/max parameters set to give the range of values required. There are one or two VCAs in the signal path to enable scaling of these controls. I may add more.

I added a couple of Tuners to the left of the Main Board because the VCOs centre on 200Hz and not middle C or anything obvious. Middle C is 0.558 on these faders. Oh and I added a couple of Presets which may give you an idea of the range of sounds possible, and I will add more (feel free to contribute to this also).

There are a couple of things I haven’t worked out yet;

1. The KBD Gate / Repeat etc switches under the ADSR, and
2. Duophony. Yep this is not merely a monophonic synth, in some circumstances you can play two notes at once. " One key pressed (monophonic) - only CV1 is sent. Two keys are pressed (duophonic): lower key sends CV1, higher key sends CV2" I have actually got this working (kind of) but I can’t get it to do it automatically. I may have to add a button to activate this feature.

I need to say a big Thank You to @stoermelder for the 8Face module which enables the presets, and for fixing the bug in the GOTO module which I have used to skip from place to place in the patch.

Also Thank You to @Nysthi for the BZ Envelope module which was the only way I could get the Proportional Pitch Control to work.

Test Patch for the Duophony function;

ARP Odyssey Development Patch.vcv (65.5 KB)

[scott_august]

This looks fun!

[john_rose]

Looking forward to the results. Once in a while I think it would be fun to reproduce an ARP 2600 work-alike.

Then I come to my senses again.

[ScreenSlave]

[EDIT] Version 1.2

ARP Odyssey Development Patch.vcv (65.5 KB)

Changelog:

• Fixed a bug where some buttons disappear when Presets are selected
• Wood Panel pic attached to this message
• Fixed main envelope controls

To Do:

• Add in Duophonic capability
• Map controls for KBD Gate / KBD Repeat etc.

[ScreenSlave]

@john_rose

Looking forward to the results.

I may have given the wrong impression - this is playable now, just a few little things to do. Also, despite my disclaimer, I think it sounds pretty close to the original although I only have the videos as a guide.

[ScreenSlave]

[EDIT] Version 1.4

ARP Odyssey Development Patch one point four.vcv (66.2 KB)

Changelog:

• Added the KBD Gate / LFO Gate controls for the ASR and the AR envelopes

To Do:

• Work out how to do the KBD Repeat / AUTO Repeat for the ADSR
• Add in Douphonic capability

I should add that I haven’t considered adding in the Pedal options on some of the controls, but if anyone wants that I will try to do it.

A big thanks also to @gc3 for his info on the VCO-1 > LFO behaviour, this was a big help

[steve]

Very impressive!

[Luca-Feelgood]

I’ve had a look at it and I have to say I’m absolutely fascinated. The whole design has probably cost a lot of work. Unfortunately I had to lower my sample rate. But that didn’t spoil the fun. Sounds good in any case.

[ScreenSlave]

Changelog: It took way longer than it should have done, but I finally worked out the LFO Repeat buttons.

• KBD Gate is the normal keyboard input.

• LFO Repeat allows the LFO to repeat the note in two ways;

  1. KDB Repeat gates the LFO repeat when a key is pressed

  2. Auto Repeat is ungated, the LFO endlessly repeats the note played on the keyboard

ARP Odyssey Development Patch one point Seven.vcv (66.7 KB)

[EDIT] I didn’t update the Presets so if you change the preset it will revert to the previous version, before this fix was added. Reloading the patch will restore the additions.

To Do:

• update the Presets to incorporate the additions
• Work out the Duophinic Capability. I have it kind of working using the Multivoltimetro from @Nysthi

[ScreenSlave]

Also To Do:

• investigate the use of the Footpedal and possibly set up a ModWheel control as a substitute.

[EDIT] The optional foot pedal was used to open and close the filter, if connected. The VCF, not the HPF. This would be in place of the Sample & Hold mixer option on two switches. It sounds like this could be fun so I will add it in.

It should be simple enough to add a switch to enable a ModWheel to do this and with that in place it could easily be adapted for use with an actual foot pedal for those who have one.