Matching Diodes, & filter FM

[Sean Costello]

Hi folks:

I am currently breadboarding a diode ladder filter. 

Two questions:

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. 

2) I want to have filter FM as part of the circuit, where the input can
be used to FM the filter cutoff.  I was planning on using a single
op-amp as a buffer, and a second op-amp tapping into the output of the
first, acting as an amplifier for the signal before it goes into the
control node for the filter.  Am I missing anything here?

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,.  It should have knobs for cutoff,
resonance, envelope sweep (knobs for Decay Rate and Amount - no attack
knob, as I want a simple decay-only circuit for maximum clarity), filter
FM, output level, possibly filter overdrive, and possibly a distortion
stage to go after the stage where the envelope signal is tapped off, but
before the filter.  Gotta find small knobs.  I have given up on the idea
on running this off of a single 9V battery for now, as it seems easier
to just put two batteries in the box.

Later,

Sean Costello