Unlocking the Yamaha E70

[mseven]

(technically speaking )

Insane as the idea would be, with something like Arduino, you could control a separate array of piggy-backed external VCO's, envelope generators etc. to drive the Analog guts of the E70...:-B

<img src="http://imageshack.us/a/img585/5619/vclfo9ddatasheet5.gif" align=right style="width:600px;margin-left:20px;border:1px solid black;">Ahha I may be starting to understand how your sugestion might go together..

Arduino could manage the CVs for many different oscillators, for example the electricdruid one of which I have three chips.

Or I suppose one LFO output could provide a CV for a second LFO even.

THat sounds fun

[David Børresen]

Done and done, I measured amperage and it rarely went above 1A but I got 3A supplies to be safe (and they didnt make 1.5 anymore).
My aim is to use 2 seperate supplies to be safe, and remove all the amps and such.
I also prefer seperate audios.
On the chopped one I had already removed everything but 1 +15 and 2-15 connections, as well as a VSS (0V before ground) and 2 grounds for the old PSU going to one of the common grounds of the organ.
So +15, 2x-15,vss, 2xGround
Switching supply didnt work as the organ didnt really draw much on the negative supply or something, in any case the -15 didnt start supplying steady voltage, just a little because the positive did.
So I already have 2 linear supplies that I bought now, but the issue as I mentioned is that I need to get that 0V somehow.
The 2 grounds from/to the old one I think I can leave out as the new PSU has its own ground?

[Guest]

Ahha I may be starting to understand how your sugestion might go together..

Arduino could manage the CVs for many different oscillators, for example the electricdruid one of which I have three chips.

Or I suppose one LFO output could provide a CV for a second LFO even.

THat sounds fun

One for each manual? That would work out fine, just get the respective voltages on the same reference before you start feeding things... : )

[Guest]

(I haven't looked at all the related detail, just the main ones)

The supplies are +/-38V, +/-27V , -20V and +/-15V, there is an SCR crowbar protection on the +/-15V and I assume you've verified the purpose of all the other supplies and transformer secondary windings and only done away with the unnecessary ones?...once again, there's a lot going on there so I trust you've figured out what supply goes where and why? : )

i.e. Notice the common grounds are made at the center-tap of each transformer secondary winding, the single ended -20V supply just has the untapped winding. The -20 feeds the power amp muting control for the headphone output

Assuming I'm following you correctly....If you're trying to generate +/-15VDC for analog, you have to stack the supplies like batteries in series so that the common point where the second supply minus connects to the first supply positive serves as the 'common ground' or 'zero volt'. so you have (-15V)-first supply+(0V/common)-second supply+(+15V) (I hope this makes sense).

The only thing is that both power supply outputs have to be totally isolated so you don't short things out. i.e. there can be no internal connection back to earth ground (or whatever the supply is being sourced from).

Switching supplies do typically have a minimum current draw before they start functioning, depending on the supply, the -15V may not supply much current versus the positive side... the E series Yamaha organs are odd in that they seem to run on a minus side of the rail (??) make sure you get your respective polarities/references right before you couple any external sources - or couple any internal ones.

Hopefully this will highlight any details you may have missed or point out what to look out for...

Done and done, I measured amperage and it rarely went above 1A but I got 3A supplies to be safe (and they didnt make 1.5 anymore).
My aim is to use 2 seperate supplies to be safe, and remove all the amps and such.
I also prefer seperate audios.
On the chopped one I had already removed everything but 1 +15 and 2-15 connections, as well as a VSS (0V before ground) and 2 grounds for the old PSU going to one of the common grounds of the organ.
So +15, 2x-15,vss, 2xGround
Switching supply didnt work as the organ didnt really draw much on the negative supply or something, in any case the -15 didnt start supplying steady voltage, just a little because the positive did.
So I already have 2 linear supplies that I bought now, but the issue as I mentioned is that I need to get that 0V somehow.
The 2 grounds from/to the old one I think I can leave out as the new PSU has its own ground?

[mseven]

<a href="http://img198.imageshack.us/img198/3179/elektonicse50.jpg" target="http://img202.imageshack.us/img202/3179/elektonicse50.jpg"><img align="right" style="border:1px solid black;margin-left:20px;width:600px;" src="http://img163.imageshack.us/img163/1139/elektonicse50t.jpg"></A>Notes to self: starting to wonder just what exactly these black knobs will be doing. Hmmm.

Coupling on the right. 3 Waveform selectors at the bottom of each panel. And 3 LFOs stacked on the left, but what Brasse Son of GX mods should those access? Might they modulate something else inside the unit as David suggested a few posts ago? Other sources of modulation? Without knowing those answers yet, how to layout the panels and allow for best design and flexibilty? Also considering there will be Arduinos mixed in there somewhere. Panels panels panels! Argh

============

Ah yes checking the doc:

"13 Synth functions are combined in the preset matrix:

4 Filter controls

• Low pass filter frequency
• Low resonance
• High pass filter frequency
• High pass resonance

5 stage Filter Envelope Generator

• Initial Level
• Attack level
• Attack
• Decay
• Release

4 stage Voltage Controlled Amplifier Envelope Generator

• Attack
• Decay
• Release
• Sustain"

Only the Filter Controls are worth modulating. Uhhh, just like it was planned a year ago. Forge ahead!

[mseven]

If I were near Iowa....

Yamaha Electone E70 Organ - $150 (Dewitt)

Very nice Yamaha Organ for sale. Works well. Ready for your playing pleasure! Call 563-357-2309 with any questions or reply by email.

http://quadcities.craigslist.org/msg/3764131339.html

[Guest]

... yeah, but if you modulate the amplitude, you get ring modulation - or tremolo if you can only manage low frequency modulation.

[mseven]

Keyman thanks. Reading up... and getting lots.

[Guest]

Amazing model by the way! All the 3-D lighting effects and reflections are terrific - a real work of art, down to the finest detail!

</A>Notes to self: starting to wonder just what exactly these black knobs will be doing. Hmmm.

Coupling on the right. 3 Waveform selectors at the bottom of each panel. And 3 LFOs stacked on the left, but what Brasse Son of GX mods should those access? Might they modulate something else inside the unit as David suggested a few posts ago? Other sources of modulation? Without knowing those answers yet, how to layout the panels and allow for best design and flexibilty? Also considering there will be Arduinos mixed in there somewhere. Panels panels panels! Argh

============

Ah yes checking the doc:

"13 Synth functions are combined in the preset matrix:

4 Filter controls

• Low pass filter frequency
• Low resonance
• High pass filter frequency
• High pass resonance

5 stage Filter Envelope Generator

• Initial Level
• Attack level
• Attack
• Decay
• Release

4 stage Voltage Controlled Amplifier Envelope Generator

• Attack
• Decay
• Release
• Sustain"

Only the Filter Controls are worth modulating. Uhhh, just like it was planned a year ago. Forge ahead!

[mseven]

Fun huh, I really enjoy photoshop - been using it for centuries it seems. I find it's helpful in visualizing.

Your comment took me to a whole new world... and in sorting that out I discovered the free "VSTHost" and "Kamiooka", and their simulation of a modular synth... and that's sure helpful.

It's easy to hear why ring modulation is great. So as you infer above, the mighty Druid VCLFO chips won't do for this application. The Thomas Henry VCO-1 seems _pretty damn good_. I see the ARP I think had DC and AC ring modulation. So far I understand ring modulation is applied just before the signal is sent for preamping or amplification. I'm wondering whether it might be worthwhile to make ring modulation available to any of the 13 inlets from the SoGX mods. Just trying to get to where the faceplate will allow all I might want to do if that's possible, which I guess it isn't :)

[Guest]

Not a bad idea to model or look at equivalent architectures before you make the hardware.

Most synths will add the two vco's of a typical patch to create the ring modulation, with the E-series, you could use a combination of upper and lower manual outputs to provide separate VCO pitches to the ring modulator, or maybe steal the control voltage going to the pedal VCF to drive a dedicated vco, much as they do on the CS lines of synths having ring modulation (the 60 & 80 for sure ). Sort of an odd-ball idea, something creative like our friend David was speaking of with his D-85's.

You could even do pwm off the organ voices that are set to a sawtooth (ramp?) feeding a comparator with a varying (cyclical) voltage i.e. your modulators...

or pump white noise into the filters, or detour the lower manual through the upper filters for paraphonic style sounds, or drive a S&H off the rhythm tempo clock (mentioned that one before) etc.

The idea is, just because the synth-organ has a 'fixed' architecture, doesn't mean you're stuck with it... just make sure whatever you do is compatible voltage/polarity and ac/dc wise. : )

Fun huh, I really enjoy photoshop - been using it for centuries it seems. I find it's helpful in visualizing.

Your comment took me to a whole new world... and in sorting that out I discovered the free "VSTHost" and "Kamiooka", and their simulation of a modular synth... and that's sure helpful.

It's easy to hear why ring modulation is great. So as you infer above, the mighty Druid VCLFO chips won't do for this application. The Thomas Henry VCO-1 seems _pretty damn good_. I see the ARP I think had DC and AC ring modulation. So far I understand ring modulation is applied just before the signal is sent for preamping or amplification. I'm wondering whether it might be worthwhile to make ring modulation available to any of the 13 inlets from the SoGX mods. Just trying to get to where the faceplate will allow all I might want to do if that's possible, which I guess it isn't :)

[mseven]

<a href="http://img7.imageshack.us/img7/4217/structure1u.jpg" target="http://img7.imageshack.us/img7/4217/structure1u.jpg"><img src="http://img7.imageshack.us/img7/4217/structure1u.jpg" style="width:600px;border:1px solid black;" align=right></A>Definitely like the sound with added VCO. I played a CS 50 or 60 about 20 years ago I can recall the similarities. So thinking this is what I'm looking for.. adding two VCOs: one to add in general to the upper keyboard, and one generally for the ring modulator.

Sweet sound when the keyboard Gate does not trigger the LFO. And so important to be able to slightly detune the VCOs. This setup seems to have the sounds I'm looking for.

[Guest]

Cool! Guess what I just downloaded... : )

Sure, the best thing is to have dual VCO, but baring the fact the E-50 only has one 'DCO' (two with the coupling mod), the Celeste function is the only one that allows digital stepped shifting of the tuning - other than the glide option and global vibrato...

Another possible option to consider is a Hard-Sync mode oscillator that is fed off the Yamaha digital oscillator feed to the VCF (since you have polyphony, it would either have to be a mono-effect, or have one per VCF...a little ambitious maybe?) Hard-Sync is a classic 'modern' sounding effect that definitely adds an edgy (sharp harmonics) to the sound.

I used something like the first page of x-4046 design from ( http://www.birthofasynth.com/Thomas_...VCO_Schematics ) for a comparable monophonic analog synth add-on a while back. Otherwise, I'm not entirely sure if you can use the related keyboard tracking signal from the VCF to drive the primary pitch of the sync'd oscillator.

Otherwise, it works by the sync'd VCO being reset whenever it receives a trigger from the reference VCO...the sync'd oscillator can be whatever pitch, but it is going to be linked to the primary...confusing, but it works in the proper context of application. this attempts to demonstrate the effect on an oscilloscope to show the technical principles... (B.T.W. not my video )

http://www.youtube.com/watch?v=gxkIhbY_KxU

</A>Definitely like the sound with added VCO. I played a CS 50 or 60 about 20 years ago I can recall the similarities. So thinking this is what I'm looking for.. adding two VCOs: one to add in general to the upper keyboard, and one generally for the ring modulator.

Sweet sound when the keyboard Gate does not trigger the LFO. And so important to be able to slightly detune the VCOs. This setup seems to have the sounds I'm looking for.

[M3me]

Not a bad idea to model or look at equivalent architectures before you make the hardware.

Most synths will add the two vco's of a typical patch to create the ring modulation, with the E-series, you could use a combination of upper and lower manual outputs to provide separate VCO pitches to the ring modulator, or maybe steal the control voltage going to the pedal VCF to drive a dedicated vco, much as they do on the CS lines of synths having ring modulation (the 60 & 80 for sure ). Sort of an odd-ball idea, something creative like our friend David was speaking of with his D-85's.

You could even do pwm off the organ voices that are set to a sawtooth (ramp?) feeding a comparator with a varying (cyclical) voltage i.e. your modulators...

or pump white noise into the filters, or detour the lower manual through the upper filters for paraphonic style sounds, or drive a S&H off the rhythm tempo clock (mentioned that one before) etc.

The idea is, just because the synth-organ has a 'fixed' architecture, doesn't mean you're stuck with it... just make sure whatever you do is compatible voltage/polarity and ac/dc wise. : )

Why doesn't someone just ~gut~ an E70 and split the components up into modules, each with it's own I/O jacks and CV inputs. Install them in a cabinet. Use a standardized sizing format that is already established. Then other modules could be added from other makers to add modulations. Every single one of the notions mentioned in "keyman2"'s post above is so easily done with a modular synth ... like child's play .. literally less than twenty seconds of patching. Of course you'd need to add the required power supply for whatever the E-70 needs.

It would be lighter, dare I say ~portable?~ .. and infinitely configured (or nearly so). As far as "just make sure whatever you do is compatible voltage/polarity and ac/dc wise." .. that is all too easy .... simply use a VCA as a controller that modulates the voltages of the E-70 systems, then modulate the VCA with some other modulator. That way you're never introducing "foreign" electrical signals into the E-70's systems. All you'd be doing is modulating the E-70's own CVs with a VCA .. exactly like using a simple pot to goof with the CVs of the E-70 .. except the "pot" is a VCA that would be controlled by other modulation sources (such as other makes of LFOs, or EGs, and so on).

A simple buffered mixer could be used to route (even complete "voices") through a Ring Mod. A few patchcords and it's a done deal.

There are many midi-cv interfaces available presently, many of which offer different protocols than the standard 1-volt per octave tracking standard. Such as hz-per octave, and so on. So getting other VCOs and filters to track with the Yamaha stuff may not be a difficult proposition.

Essentially gutting an E70 to make modular synth modules out of it. You're almost at that point as it is.

I like the idea so much (now that I have thought of it) that I may just seek out an E-70 for that purpose. It seems like a wonderful solution for those so inclined.

[Guest]

I gather most users have the idea to be able to 'enhance' without affecting the default features? It looks like David is leaning to do something more like on the Korg MS-20, where you have a side patch pane? If that's the approach/inspiration, it's at least a compromise that does not do away with the rest of the E-70 (E-50 etc.)

It would be idea to find 'dead' E-series or D-85 organs and scavenge them for the related CS style filters/vca's and (only one) analog VCO in the D-85 which also has analog delay/chorus (BBD) chips... either way, it's a bit of work and more of a hobbyist approach. More ambitious people have idea's of creating Arduino/PIC based retrofits that do away with the need to rely on the Yamaha digital engine...that would be the best of both worlds.

Otherwise, unless you have a specific reason for wanting to use the older CS style analog circuits, or happen to have the adaptable organs, the newer & re-issued hardware is allowing a very practical opportunity to have the analog/modular experience without having to go through the time and related expense - definitely a 'labor of love' for lack of a better expression... ; )

Why doesn't someone just ~gut~ an E70 and split the components up into modules, each with it's own I/O jacks and CV inputs. Install them in a cabinet. Use a standardized sizing format that is already established. Then other modules could be added from other makers to add modulations. Every single one of the notions mentioned in "keyman2"'s post above is so easily done with a modular synth ... like child's play .. literally less than twenty seconds of patching. Of course you'd need to add the required power supply for whatever the E-70 needs.

It would be lighter, dare I say ~portable?~ .. and infinitely configured (or nearly so). As far as "just make sure whatever you do is compatible voltage/polarity and ac/dc wise." .. that is all too easy .... simply use a VCA as a controller that modulates the voltages of the E-70 systems, then modulate the VCA with some other modulator. That way you're never introducing "foreign" electrical signals into the E-70's systems. All you'd be doing is modulating the E-70's own CVs with a VCA .. exactly like using a simple pot to goof with the CVs of the E-70 .. except the "pot" is a VCA that would be controlled by other modulation sources (such as other makes of LFOs, or EGs, and so on).

A simple buffered mixer could be used to route (even complete "voices") through a Ring Mod. A few patchcords and it's a done deal.

There are many midi-cv interfaces available presently, many of which offer different protocols than the standard 1-volt per octave tracking standard. Such as hz-per octave, and so on. So getting other VCOs and filters to track with the Yamaha stuff may not be a difficult proposition.

Essentially gutting an E70 to make modular synth modules out of it. You're almost at that point as it is.

I like the idea so much (now that I have thought of it) that I may just seek out an E-70 for that purpose. It seems like a wonderful solution for those so inclined.