[sdiy] Subtle Chorus (including Dimension D emulation)

[JH.]

Hi,

just wanted to give you a quick update of my upcoming (fall 2008) "Subtle 
Chorus" PCB project, which, among other things, will be able to emulate a 
Dimension D, (using original ICs and all), plus "Dim T" (Same topology but 
with two 20-stage phasers instead of BBDs), plus generic true-stereo, 
dual-BBD chorus.
Depending on what configuration you want, this will use one, or up to four 
PCBs. (Dim D emulation needs two PCBs.)

 The "Subtle Chorus" is a variable project consisting of 3 different PCBs 
that can be combined for various functions.

  a.. You can build a rather simple, true-stereo, dual-BBD Chorus with 
voltage controlled Chorus Rate and voltage controlled Chorus Depth, using a 
single PCB.
  b.. You can emulate the famous "Dimension D" (Trademark of Roland / Boss) 
sound with it's unique filtering and presets, using two PCBs, the "Dim D" 
(You even have the choice between vintage HA1457W opamps, or more common 
TL071 / TL072 opamps.)
  c.. You can build a similar effect that uses 20-pole all pass filters 
instead of BBDs, using three PCBs, the "Dim T".
  d.. And you can build an overkill effect device that allows to choose 
between the Dim D and Dim T effect, using 4 PCBs, the "Dim TD" version.
So far, the BBD board design is finished; main board will be the next.
Documentation is here:
http://www.jhaible.heim.at/subtle_chorus/jh_subtle_chorus.html

The BBD board needs 2 x MN3007 and 2 x MN3101. These are quite easy to get, 
compared to other vintage BBDs.
The Dim T version doesn't need any BBDs, of course.

JH.