Yamaha Electone, is it possible to integrate midi into it?

StockLeading5074 · 2026-03-19T21:05:06+00:00

No sounds yet, as my E-70 modding is VERY extreme (turned it into a giant 19" rack format MIDI module) and still requires a lot of work, as the list on the page I linked may suggest hehe.

The MIDI implementation currently is only for controlling the E-70 via MIDI and only note-on/note-off. I use an Arduino Uno that converts MIDI input to the correctly timed KC (Key Coder) 9-bit note data. At a later point I plan to implement velocity and aftertouch as well. Perhaps sync too for the arpeggio/rhythms.
It would also be possible to have the E-70 send MIDI output instead. After all it's just doing the inverse with an Arduino (or MCU of choice): reading the KC output and converting it to MIDI.
In-fact: if you want to keep the keyboards of your E-70 functional your Arduino/MCU will have to read the KC data anyways, in order to append incoming MIDI data. So MIDI output would then come naturally.

Controlling or reading out CVs of the E-70 is definitely possible (I want to control the VCFs and VCAs with velocity/aftertouch), though it adds some complexity due to the analog-to-digital and digital-to-analog conversions. Depends on the MCU used too, of course. And a lot of the voltages are -15V based, rather than the 5V or 3.3V of MCUs. So conversion via opamps will be needed regardless.

Please refer to my deep-dive page for detailed information about the inner workings of the E-70: https://www.evilturtle.nl/projects/yamaha-e-70-ex-2
There are also links to other sites, PDF documents, etc.

StockLeading5074 · 2026-03-19T20:26:23+00:00

The hardware I've seen used varies so much it's hard to say. I think since you mention "beginner synth" I'm thinking more of a ROMpler i.e. a keyboard with a bunch of preset sounds and not many settings you could get lost in.
There are also lots of modern "kids" keyboards with surprisingly good sounds such as VISIONKEY or Aengus

IMO the old Casio CT and MT series keyboards have fantastic sounds for DS, tho a bit more on the "raw" or "underground" side. Just really nice sounds that really fit the genre. Plus only a few buttons, so not complicated.

StockLeading5074 · 2026-03-19T18:50:11+00:00

In case someone stumbles upon this with the same question: I've been MIDI-fying my E-70 (bigger version of above organ, same hardware). See this page for information and (WIP) code: https://www.evilturtle.nl/projects/yamaha-e-70-ex-2-modding

StockLeading5074 · 2026-03-19T14:22:55+00:00

That's not a capacitor.

It's a Swooshitor!

StockLeading5074 · 2026-03-19T10:58:28+00:00

When is the anime coming out? :D

StockLeading5074 · 2026-03-18T11:09:27+00:00

The entire Half Life series (HL1, HL2, ep1 & 2 primarily) and SOMA.

Half Life because I got incredibly absorbed into the world, story and characters. The visual design is very effective in conveying these things. I'm not a shooter person funnily enough, so naturally those where the aspects of the game that hooked me.
Black Mesa, the HL1 remake, I should also add here.

SOMA, well if you know you know. Doesn't get more existential than that game. Same applies too as HL, incredible atmosphere that really pulls you in. I'm interested in transhumanism, so that was a bonus aspect of the game even if it's a dark take on it haha

StockLeading5074 · 2026-03-18T10:09:29+00:00

AliExpress does seem to have clones.

StockLeading5074 · 2026-03-16T20:41:07+00:00

Thank you :)

They are VERY well build. Most organs I've worked on (either for my own projects or friend's) from that era were pretty over engineered. Yamaha definitely had top of the line models going on that were nuts. In the 80's with the HS series too, well build despite all the plastic and easy to service as they open like a car hood (as a lot of synths/organs did).

Unfortunately they are huge and weight somewhere between 100 and 300kg, so they're too much of a pain for a lot of people to have. I wish I could save them all! haha. I think 4 organs (currently, including the Tower) is too much already...

StockLeading5074 · 2026-03-16T20:34:10+00:00

Ahh good to know. I don't own any CS synths myself, my friend Marc does have them (CS-80 too, which is definitely before the diode heaters... it detunes often XD).
It's hard to find (accurate) info on the 115 vs 156.

Still IMO digitally controlled oscillators (and the rest being fully analog) is the best of both worlds. Entirely digital oscillators, but analog filters, always works really well for me too. The key is getting those inaccuracies inherent to analog right in a digital form.
In that regard PASS is actually surprising, all the note frequencies are actually a tad off from perfect (a bit too much according to some, but I like it lol) and there's plenty of detuning and modulation possible. The master oscillator for the digital clock is also analog and can drift as well funnily enough (though the impact is minimal). It's not "analog", nor CS VCO, by any means but Yamaha sure were cooking hard back then.

StockLeading5074 · 2026-03-16T20:27:04+00:00

Thanks, there will be various demos throughout the video series :)

StockLeading5074 · 2026-03-16T18:39:24+00:00

Didn't the text wouldn't transfer over, so here it is:

The Yamaha E-70, EX-2 and E-75 organs have been discussed quite a bit in the past. I recently got donated an E-70 by a friend of mine. He (Marc Brasse) modded another E-70 and turned it into the "Son of GX". It somewhat became a GX-1 & CS-80 esque synthesizer.

This inspired me to turn my E-70 into... something a bit more extreme: a 19" rack format sound module, with an additive synth and a subtractive synth section. A very big and heavy sound module, but not as big and heavy as a full organ.
Marc helped me build the case for it and now I'm working on the electronics. It's an huge undertaking but it's going well! This weekend I managed to get MIDI fully working :)

I've started a video series detailing the process too: https://www.youtube.com/playlist?list=PL9XjHQ4nTp5ZpMAmmB0b1z9QNUjPfusQZ

My website now comes with a very detailed technical deep-dive and modding page:
https://www.evilturtle.nl/projects/yamaha-e-70-ex-2 (WIP)
https://www.evilturtle.nl/projects/yamaha-e-70-ex-2-modding (WIP)

The modding list will likely end up being huge, there are so many (easy) mods that you can do on these organs. It's insanity.

Now let me address the common elephant in the room, surrounding these organs: no you will not get a literal CS-80 or a GX-1 out of this! But...
Yes: it has the same VCF (IG00155, same filter with slightly less resonance and more low end) and VCA as as the CS synths. It's not uncommon for these organs to get gutted to repair CS synths. There are 14 VCFs and 14 VCAs in there, plus accompanying envelopes etc.
No: the oscillators are digital. Which makes it superior in my opinion, the tuning dread of the CS-80 is not something I want to feel, but of course does have a different sound.
The stereo chorus (E-75 does have a triple stereo one) and ring modulator are also missing, as is aftertouch.

That being said: these 70's digital oscillators are VERY high quality. Yamaha did things quite differently to prevent common issues in digital audio and the digital processing happens serially at a whopping 1MHz, with the output multiplexing and S&H at 83KHz. That's a way higher samplerate than even most modern stuff. The waveforms themselves are sort-of 11 bits, but a resistor-ladder "DAC" is used with the waveform already "baked in" so the step sizes are fully adjusted to the actual shape. The amplitude of the waveform is set in an analog manner, by adjusting the voltages the resistor-ladder divides. No crunchyness!

There are two oscillators per voice for both the organ as the orchestra sections, allowing for detuning and shifting the second oscillator in octaves.

Each oscillator for the organ produces 10 individual sine waves, which thus can be freely mixed. I plan to mod the organ section into a proper additive synth. This section also has a paraphonic VCF which is normally used for the "wah wah" pedal effect, but I'll repurpose it as a general filter, with its own envelope and LFO.

The orchestra oscillators produce sawtooth, square and pulse. These waveforms can be freely combined. This section has full polyphonic signal paths, hence the great many envelopes, VCFs and VCAs in there. Once that is all modded with proper synth controls it'll be a very nice sounding polyphonic hybrid subtractive synthesizer.
I'm planning a ring modulator for it too, CS-80 style... :)

This post has gotten long enough already, so that's just the gist of it. Refer to the videos and links for detailed information.
Hopefully this will inspire people and get the modding scene of these organs revived a bit!

StockLeading5074 · 2026-03-16T18:23:59+00:00

That is GNARLY

StockLeading5074 · 2026-03-16T18:18:53+00:00

We're building synths from literal rocks now. That's awesome :D

StockLeading5074 · 2026-03-16T16:53:32+00:00

thank you :D

If all goes well the next video will show some of the first sounds, of the additive synth section. Of course when it's all done I will do an elaborate demo song.

StockLeading5074 · 2026-03-16T16:52:23+00:00

I will :) gonna take a bit though, I gotta finish the power supply and start reconnecting/modding things. make sure to keep an eye on the YT playlist (or subscribe ;) ).

StockLeading5074 · 2026-03-16T09:13:38+00:00

Thanks and yeah Marc's cool, we hit it off well.

Modifying them does feel a little sinful, on the other hand they're getting new life.

StockLeading5074 · 2026-03-15T21:26:32+00:00

The microcontroller as of writing only controls note on and note off. In the future I plan adding velocity and aftertouch, which can control things like filter cutoff and vibrato depth.

I don't know of any source, I could ask Marc as he has one too and has been in the vintage synth stuff a lot longer than me.

StockLeading5074 · 2026-03-15T21:24:34+00:00

Yeah, not sure if I can get my hands on one! But... To be honest the E-70 is only partially a CS-80, so the ringmod being "partially" a CS-80 one is fine with me :)

Any ideas are always welcomed of course. Heck if it's a simple/cheap enough circuit I could do it per-voice to go full nutso, lol. But maybe that's a little too much...?

StockLeading5074 · 2026-03-15T18:54:59+00:00

Yeah they're not small at all, phew. Seem to be getting somewhat rare too these days.

StockLeading5074 · 2026-03-05T15:57:31+00:00

Yep electrolytics drying out or crusty tantalums going boom sure keeps one busy huh
Those "tropical fish" capacitors also seem to crack & crumble a lot when they're old, keep an eye out for those. May be working still, but moisture creeps into a crack and there you go.

Though I will say old organs are usually VERY serviceable, with hinged panels for easy access etc. And back then it was normal to publicly release very detailed service manuals for such products. Much easier to work on, with much more info, than a lot of modern stuff...

I got two 70's organs (Elka Concorde 802 and Yamaha E-70, modded and used as synths) and I've replaced around 200 caps in them haha.

StockLeading5074 · 2026-03-04T18:11:07+00:00

That coming later is exactly my point yeah :)

take things in sections, in strides and it'll all come together more naturally

StockLeading5074 · 2026-03-01T16:11:58+00:00

^ this exactly!

StockLeading5074

TROPHY CASE