[sdiy] Shoot me now :) WAS: no free lunch :(

[David G. Dixon]

OK, I think I might have been a little too hasty in my assessment of the
2164-as-tempco.  Bear in mind that I have made so many measurements over the
last few days under so many different circumstances, that I have gotten
myself a little bit confused.

However, a private email from Ian Fritz made me realize that I'd neglected
to re-install the 7.5k MODE pin resistor in my breadboard circuit.  When I
did that, the problem of the changing voltages largely disappeared.

So, this is definitely related to the distortion specs of 2164.  Put in the
MODE resistor, distortion is decreased, and the gain stays virtually
constant at a constant control voltage.

However, there are still major issues regarding the use of anything
significantly larger than 30k on the input of 2164, but that's a story for
another time.