[sdiy] Yves Usson's Minimoog Filter

Matthew Arthur mathewarthurtech at gmail.com
Sat Jun 10 08:45:15 CEST 2023

I believe the schematic indicated is completely workable. Minimoog service
documents are easily found online, if you wish to further reassure yourself
of it's basic design.

I believe Transistor choice should not prevent a ladder filter from

At least, I've built basic ladder filters with unmatched 2n3904/6's and
they sounded fine.

On Sat, Jun 10, 2023, 12:15 AM David G Dixon via Synth-diy <
synth-diy at synth-diy.org> wrote:

> Hello SDIY Team,
> I've built a ladder filter on my own PCB layout from Yves Usson's Minimoog
> ladder filter schematic, and I must confess that the results are less than
> stellar.  The filter works, but not terribly well, and it sounds nothing
> like a Minimoog.  I used 2N3904 and 2N3906 instead of BC547 and BC557, but
> I matched all of the transistor pairs in the ladder, and matched the four
> transistors at the top and bottom of the ladder as well as the other four
> transistors, using Ian Fritz's transistor matching circuit (which I also
> laid out and built on a PCB).  I did not try to match the one PNP to the
> current driving NPN below the bottom of the ladder.
> Does anyone here have any experience with this schematic?  Will it change
> anything if I replace the 3904s with 547s, etc?  Everything else was
> exactly as specified in the schematic.  This was my second attempt to build
> from an Yves Usson ladder filter schematic.  My "Raging Bull" Taurus filter
> didn't work at all.
> I just want to know if there is some fundamental flaw in this schematic
> before I spend too much more time with it.  Any insights would be most
> appreciated.
> Dave Dixon
> _______________________________________________
> Synth-diy mailing list
> Synth-diy at synth-diy.org
> http://synth-diy.org/mailman/listinfo/synth-diy
> Selling or trading? Use marketplace at synth-diy.org
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://synth-diy.org/pipermail/synth-diy/attachments/20230610/9d268bcf/attachment.htm>

More information about the Synth-diy mailing list