>I did get my VCO working yesterday but spent an inordinate amount of time
>calibrating it. I really love the instructions (especially the theory of
>operation). Yes, I had problems with the power cable and that added to the
>time it took to calibrate it; I was able to fix the pins on it properly.
1) If you are use a freq counter, then use the SYNC I/O jack with the switch
set to SOFT.
This seems to make my freq counter the "happiest": ie not bouncing the
digits.
2) I take it you eventually were happy with the calibration.
3) Using a Pro2000 and a freq counter, I start in the middle of the pot
rotation and
can get to tracking point in about 1 minute. How long did it tke? What was
the
input device?
>
>I do have a question for Paul and other VCO users: I'm experiencing a
>frequency drop when I switch from soft to hard sync (with nothing at the
sync
>input!). At 1440 Hz in the hard sync position, it drops to about 1360 Hz in
>soft sync. I don't hear a pitch drop at around 90 Hz (I don't trust my freq
>counter at this low freq), so it seems to scale differently in the hard and
>soft sync positions. Does anyone else notice this behavior?
Look at the schematic. In SOFT mode, the sync pulse is feeding back into the
VCO.
So, it would not surprise me if it dropped some because of delays in the
circuit.
I haven't paid much attention to this: I will investigate.
The soft sync is a little "touchy" and I may need to adjust a R or C.
99% of the time, HARD sync is what you will use.
Paul S.