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The Yamaha E-75
Synthesizer Organ - 1981
Blue Book says
2 61-key Manuals
25 Pedals w/Sustain
3 Independent Polyphonic Orchestra Sections (Upper, Lower, Pedal) w/Bright & Dial Transposition Controls
Vocal Ensemble (3), Vocal Ensemble to Lower
String Ensemble Presets (3), String Ensemble to Lower
2-Speed Split Tremolo System
Vibrato and Reverb
Symphonic Chorus w/Celeste
Auto Rhythm (64) w/Break Variations, Digital Display
Rhythm Sequence Programmer
Preset Board (Drawer)
Preset Pistons (6) w/Knee Lever Cancel
Independent Flute and Orchestra Celeste for each Keyboard
Stereo Headphone & Aux Out Jacks
Complete ABC Fun Blocks System w/Multi-Bass Patterns
Roll-Top Fallboard w/Lock & Auto Power Switch
4 Channel Sound System
MSR Price 11225€
Outside the E-75
This really is an impressive piece of wood. It is actually a polysynth, build into a respectable and heavy organ. Probably to meet the wife's taste for the permission to put this instrument into the living room :-)
By the way this is my second Electone which has a funny small bench. I am feeling like a small school boy in front it.
The full console
Inside the E-75
This organ is a hybrid type. All control logic and all oscillators are digital, the filters, amplifiers, effects and drums are analog. I think, this was the last analog organ that Yamaha has built.
The flute tabs are digital, their tones are created using wave memory chips. And it sounds really good! Nine flute tabs for the upper manual, 6 for the lower plus Percussion. Polyphony is limited to 11 voices per manual. Really interesting are the Celeste Tabs. They can detune the flute tabs in 3 degrees, meaning that there are 2 sets of flute oscillators per key. This produces gorgeous beats of the flute tabs.
There are also Celeste tabs for the second part of the organ: the orchester section. It shares the PASS technology of the famous CS80 synthesizers.
The main difference to the CS80 is that the E-75 has 2 manuals instead of one and twice the oscillators. The Oscs are digital. At least they do not get out of tune, as with the CS80. When the lower manual is coupled to the upper manual, then you have an original CS80 signal flow: 2 oscillators per voice (the 2nd Osc pair is disabled) go through 4 VCFs, i.e. two sets of high pass / low pass VCFs per voice. The preset keys of both upper and lower sections remain active. Great thing! The polyphony is limited to 7 voices for each manual and 1 for the pedals. Certain features of the CS80 like LFO, Noise and cross-modulator are missing.
Preset Synthesizer is a CS80 under the hood!
The presets are hard-wired in 5 PCB boards, using the following parameters:
- VCO Waveforms: sawtooth, rectangle 50%, rectangle 25%
- VCF: frequency & resonance separate for both low pass and high pass filters, A, D1, S, D2, Intensity
- VCA: A, D1, S, D2
Modifying the presets is rather easy. Each parameter is programmed by a physical resistor - just replace it by another value. The VCO waveform is switched by diodes, the 3 different waves may sound in parallel.
Better than modifying the presets is having knobs for tweaking the sound live. There is convenient space for the knobs when removing the slide cover of the organ, I made a new wood panel that fits into this slot, disabled the resistors of the preset FUNNY2 of the upper manual and wired potentiometers to the preset boards. Now the face of the E-75 looks like the following picture. Notice the upper grey knobs and the row of switches (from a Böhm Top Sound by the way). I am still searching for black knobs that fit better to the rest of the organ.
Even there are now buttons for LFO and Noise, these modules are missing in this model. My next plan is to find a circuit for them.
The knobs and buttons on top are the new elements to enter a new dimension of the organ.
Want more details? I wrote a German article about this outstanding organ in amazona.de, follow this link here.