Since I'm not the one to originally post the question about calibration
of the Conn tuner I may be away out in left field here.  Being the
proud possessor of an out-of-calibration ST-2 I interpreted the problem
to be, "How do I get this thing to be accurate over an entire octave."

Alas, mine is sufficiently out of calibration to be a real pain to use
properly and I sometimes use it together with a frequency counter when
I want to be really accurate, such as in musical box tuning where you
can't put weight back on a treble tooth without affecting the tone.

The tuner uses paper capacitors (read: "It drifts a lot.") with
a multi-tapped inductor in the tuned circuits.  The latter is variable
over its full range by altering the magnetic gap using the Sharp-Flat
knob.  The unfortunate part is that the switching circuit, as I recall,
does a lot of mixing and matching with the capacitors making things
somewhat interdependent when it comes down to figuring out what to
tweak next.

Sure, I could trudge through all the math and probably get it right
but, gee, life's much too short!  Does anyone have access to a copy of
the manufacturer's calibration procedure?  At least it would give a
place to start.

Besides being a great device for tuning xylophones (haven't tried it
for that, though) it is a terrific display of how an instruments
overtones (partials) can dramatically differ from its harmonics.
Something anybody into tuning instruments really should know.  If you
think pianos have stretched octaves, have a look at musical boxes!

Jim Heyworth,
Sechelt, B.C., Canada