Orchestrion

A Strings/Choir synthesizer based on 12 oscillators with the AS3340 chip. I have chosen this VCO to get a very stable tuning over the octaves.

each oscillator can be tuned individually. 3 oscillators are grouped together. There are 4 groups and each group has its own CV-1V/Oct input.

With an appropriate controller, the device can be played polyphonically in 4 voices.

There is a CV input for all VCOs at the same time

There is an adjustable ensemble effect that is always split between the 3 VCOs in a group

The entire device contains individual modules.

Strings and Choir can be mixed with a 5K Lin - Poti.

A separate saw-output can be connected to an external Filter or Resonator. It can be connected back

to the VCA-input

Delay is an option i didn't built in at this time

UPDATE 07/2022: changed the Steiner VCF with a Moog-VCF for a cleaner Strings-Sound

                                changed the Mixer-Resistors from 100K to 47K

                                added a separate Poti for the Choir-Level in the Mixer

The Power-Supply

This is a very simple symmetric Power-Supply but it works fine in this device.

I used large cooling plates and the outputs are fitted with fuses. (1A)

if you have enough space then i recommend larger capacitors than 1000 uF

A VCO-Modul:

The VCO-Circuit:

Breadboard Platine Layout

The 3-Phase LFO

The 3-phase LFO is a simple sine wave LFO.

you can control the Speed and intensity

The signal is then shifted in 3 phases - this way you can create a chorus or ensemble effect via the CV inputs of the VCO

The phase shift is set with the 3 trimming potentiometers

The 3-Phase Circuit

Breadboard Platine Layout

Mixer Circuit

Moog-VCF

This is a clone of the Moog Transistor Ladder-Filter.

A very beautiful Filter for a Strings-Synth.

You find the original Circuit at the YuSynth-Site (Minimoog-VCF):

http://www.yusynth.net/Modular/index_en.html

VCF-LFO

A Sine-Wave Generator that runs on a very slow frequency.

The right Trimmer sets the frequency

VP-330 Filterclone

A clone of the VP-330 Choir-Filter/Formant

It turns a sawtooth into the famous sawing vocoder-like choir sound

There are 7 lines  which can be mixed individually via pots.

The frequencies go from 200 to 3300 Hz.

Based on the settings you can choose a male or a female sounding choir

The Video demonstrates this Filter

AR-VCA

The Chips are AS 3310 for the AR-Envelope and the AS 3360 for the VCA-Potis

The Decay isn't connected and the Sustain is bridged via a 220 Ohm resistor on pin 9

Attack and Release -Potis are 100K Lin