[sdiy] Variable Slope Filter / Phaser

[Pete Swarbrick]

Hi Jurgen

Sounds like another winner; I love it! I would build one if you go ahead
with the PCBs.
[Also reminds me how I (still) want an OB-8 :<)) ]

Pete


-----Original Message-----
From: synth-diy-bounces at dropmix.xs4all.nl
[mailto:synth-diy-bounces at dropmix.xs4all.nl] On Behalf Of JH.
Sent: 15 March 2009 22:00
To: analog heaven; synth-diy at dropmix.xs4all.nl; MOTM List
Subject: [sdiy] Variable Slope Filter / Phaser

I think about making PCBs for this.

A mean little module from my JH-3 Modular.

6 filter poles, realzed with OTAs and combined FET / Bipolar buffer
stages.

Variable Slope function for 6-pole VC LPF.
Voltage controlled Pole Spread for Phaser mode.
Zeroes switcahbel in pairs, i.e. a lot of combinations of all pass and
low 
pass stages. Positive and negative feedback. Positive and negative
wet/dry 
mix. Rather special overdrive behaviour (Dirty!), and (IMO) pleasant way
of 
breaking into oscillation.

Old picture (from JH-3): 
http://electro-music.com/forum/phpbb-files/jh3_varislope_phaser_887.jpg

Demo 1 (Arpeggio from OB-8, with delay and reverb. First few seconds dry
- 
then playing with phaser.):
http://electro-music.com/forum/download.php?id=16715

Demo 2 ( This is something I recorded a few years ago. I don't remember
all 
the details. But it was a Split on the OB-8, bass sound on left hand and

organ sound on right hand, and the whole thing was processed with the 
Variable Slope Phaser / Filter to get that "pulsating" sound.
Lots of delay and reverb as well, obviously.):
http://electro-music.com/forum/phpbb-files/oct_06_zwischenstand_edit_189
.mp3

JH. 

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