Juergen Haible Triple Chorus in MOTM

further links: http://www.dragonflyalley.com/jHTripleChorusConstruction.htm

backup here:Dragonfly Alley MOTM Synthesizer Jurgen Haible _Triple Chorus_ Construction.pdf

BOM:

The Equalizer potentiometers are 10k linear each (3 in total).
You may want to add an input level potentiometer: 10k log ... 50k log are good values.
Input / output jacks depending on what signals you want to bring out.
Mode and bypass switch can be realized with a rotary switch or with a set of toggle switches - more about this later.

List:

jh_triple_chorus_bom.pdf

Reichelt shoppingbasket

http://www.reichelt.de/?ACTION=20;AWKID=41401;PROVID=2084

Building Tip from Juergen.H

The PCB board - power on-board. 
It all fits onto a 160mm x 100mm board. It contains a power supply (less transformer and primary fuse). You only have to connect 18V AC from a transformer. (And you must be qualified to handle the mains voltage - fuses, insulation, safety aspects. If in doubt, don't wire the mains voltage, but use an insulated 18V AC wallwart instead. Mains voltage can be lethal.)
Here's a (preliminary) component overlay:
(click on the image for a full size version.)

Alternative +/-15V supply (MOTM and Synthesizers.com, etc.) 
I've also included the footprints of MOTM and .COM power connectors, if you want to run the board directly from 15V, without a transformer of its own.
I've placed the footprint for the connectors beneath the (secondary) fuse, because you never need both at the same time.
When connecting to 15V DC, you must omit a lot of the power supply components, too.
Click on the following links for the alternative component overlay for 15V DC: MOTM version,   Synthesizers.com (.COM) version.
By the way: The whole circuit only needs the -15V part of the MOTM and .COM system; the +15V pins of the connectors are unconnected.
The audio signals are centered to 0V nevertheless, of course, due to AC coupling of inputs and outputs.
Signals are weaker than your usual modular system. Input can be attenuated with a potentiometer. Output is roughly "Line level" and can go directly into a mixing desk or sound card.

jh_triple_chorus_overlay.pdf

jh_triple_chorus_connections_1p2t_switches.pdf

jh_triple_chorus_sch_page1.pdf

jh_triple_chorus_sch_page2.pdf

Background from J.Haible website

 The lush Sound of the Solina (TM) Ensemble is created by 3 BBD delay lines that are modulated in a unique way:
There are two 3-phase modulation generators, one running at slow speed ("Chorus"), and one running at high speed ("Vibrato").

We'll focus on one of the modulation generators first, "Chorus": the slow one.
"3-Phase" means that the modulation generator has 3 outputs, each of which's phase is roughly 120 deg apart from the previous output.
Let's call them "0 deg", "120 deg" and 240 deg" - it's easy to see that, with 360 deg describing a full circle, the three modulation outputs a modulation generator are equally distributed around a circle. They are routed to the CV inputs of the 3 BBD's clock VCOs. Modulation of a BBD line causes a pitch shift similar to the Doppler effect of  a moving sound source, so with the 3 BBD lines modulated by the 3-phase control signals, a sonic image of  3 sound sources that are moving along the same circle, with equal distance to one another along the outline of the circle, is created.

Actually, each BBD clock VCO is controlled not by a single modulation generator, but by a combination of the slow and the fast generator.
BBD1 sees a CV that is combined from the Chorus generator's "0 deg" output and the Vibrato generator's "0 deg" output.
BBD2 sees Chorus "120 deg" and Vibrato "120 deg".
BBD3 sees Chorus "240deg" and Vibrato "240 deg".