Hi everyone,
I can offer some comments on the above:

1. The sine wave from the A-110 is generated from the triangle wave
(through a voltage divider, then taken across a diode, and the
exponential type curve produced is then scaled up, which is why the
sine wave is not very sine-like!). Thus there is no way they should
have different frequencies! Resistor R52/capacitor C9 used in this
process don't affect the signals frequency. (Same method is used for
the sine wave in A-111, A-145 and A-147.)

2. The main capacitor in A-110 controlling the frequency ranges is C3
- in theory halving this will double all frequency ranges; in
practice, if you were to do this, I don't know what the 'quality' of
the waveforms would be though!

3. The max freq I can get from both my A-110's is about 10500Hz: top
range, with about 8V input. Max from A-121 is 13500Hz (A-122 similar).
I haven't spent much time looking at the filters (yet!), so I don't
know what the limiting factor is.

Tim

[The views expressed above are entirely those of the writer and do not
represent the views, policy or understanding of any other person or
official body.]