[sdiy] CMOS VCF and VCAPF

[Osamu (Sam) HOSHUYAMA]

Hello List,

I have updated my site a little bit.

    http://www5b.biglobe.ne.jp/~houshu/synth/index.html

First I added link to the space for Mike Irwin's schematics and photos.
No update with the contents.  I hope Mike sends me new schematics. ;-)
(I visited his home and was fascinated by his phasers and flangers.)

    http://www5b.biglobe.ne.jp/~houshu/synth/mike_irwin/


Also, I put my new CMOS VCF inspired by the discussion on all-cmos synth 
on this list.

    http://www5b.biglobe.ne.jp/~houshu/synth/VcfMos0206.GIF
    http://www5b.biglobe.ne.jp/~houshu/synth/CmosOta.GIF

The schematic is complicated to make it understandable, but actual board 
is quite simple.  Just 2 4069UBs and 4 transistors are needed.
The VCF uses CMOS OTA structure used in Pearl phaser PH-03.
Occasionally, MC14069, the same maker as in the PH-03, gave me the best 
results.  Sound of the VCF is of course lo-fi.


I also put my idea of voltage-controlled all-pass filter for phaser
suited for Mike Irwin's CMOS VCR structure.

    http://www5b.biglobe.ne.jp/~houshu/synth/PhaseFet0205.GIF

I first thought I should not publish it before breadboard test, but 
in a couple of weeks, my family will come to Ottawa and I think I'll not 
have time for synth diy for a while, so I publish it now.
If someone would try my idea with Mike's VCR, I'd appreciate it.

I hope you enjoy.

Sam Hoshuyama
-- - ---  - -- ------ - -------- -- - ---- -
Osamu (Sam) HOSHUYAMA      houshu at rogers.com
                              Ottawa, CANADA
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