[sdiy] Synthi A trapezoid

[ganesha]

Hi All;

Sorry for cross posting, but does anyone have the
correct procedure for callibrating a synthi A
Trapezoid?
The steps on the hintonpage are not very clear to me.
1 ENV Set Trapezoid speed to 65Hz with PR12
2 ENV Set PR13 clockwise.
3 ENV Adjust PR8 for minimum residual signal.
4 ENV Adjust PR13 until signal just reappears, then
back off to zero.

How should I set the attack, decay, on and off
potentiometers during step one because they also
determine the frequency?
Step 3: there is no PR8 on the schematic. Do they mean
PR7 which is the 2M5 trimmer or do they mean VR8 which
is the decay potentiometer? Should I simply
connect a vco to the signal in of the trapezoid and
adjust till I hear no signal anymore? I tried that,
but with pr13 fully clockwise I had a constant
signal that wasn't affected anymore by tr7 or VR8.

Any help is much appreciated.
regards, Kris


		
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