Matching Diodes, & filter FM

Steven Cook steve at
Thu Jul 30 00:16:16 CEST 1998

Sean Costello wrote:
> Hi folks:
> I am currently breadboarding a diode ladder filter.
> 1) How should I go about matching the diodes in the circuit?  I have a
> new multimeter, & a good breadboard w/a power supply (+12V, -12V, +5V),
> so any simple circuits would be appreciated.

> I have high hopes for this little box.  It will be based on a Practical
> Electronics design, powered by 2 9V batteries, and should fit in a
> Hammond 1590BB box when finished.
> Sean Costello

I've just built a transistor ladder filter without matching anything and it
seems fine - no noticeable dc breakthrough. Might be worth trying.

Is your filter the one from the Minisonic? I built one years ago and remember
it having a really warm sound.

I used to mix the output of this filter with the input signal, which cancelled
out when trimmed just right, leaving (I think) a sort of highpass response.

Good luck!


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