Cgs synth

I'm ready to wire up a sub oscillator using the 3u schaeffer design
and I'm a little confused about wiring the prescale switches!

How do you wire in the prescale/bypass switch?
It looks like it should be a SPDT, with A going to the top, & B to the middle. I'm not
sure what the bottom connects to, though! Does it go straight to C?

How does the 3/5/7 prescale swith fit in?
What type of switch is used? How do the /2, /3, /5 & com pads connect, & how does
this relate to the 3-7-5 options on the switch?

>How do you wire in the prescale/bypass switch?
>It looks like it should be a SPDT, with A going to the top, & B to the

middle. I'm not

>sure what the bottom connects to, though!

>Does it go straight to C?

Correct! The switches usually work up-side down though, so when the switch
is in the upper position, the lower contact is the one working, so you may
find you need to rotate the switch, or swap the A and C wires.

>How does the 3/5/7 prescale swith fit in?
>What type of switch is used? How do the /2, /3, /5 & com pads connect, &

how does

>this relate to the 3-7-5 options on the switch?

If you are using toggle switches, i.e. you have wired bypass as described
above, a second toggle switch, this time a SPDt Center-off type, is wired
with its top connection to /3, its bottom connection to /5 and its center
connection to COM. (again you may need to swap the top and bottom
connections.) /7 is automatically selected when the switch is in the center
position. This is done without any extra wiring. When wired like this /2 is
not used.

Alternatively, a two pole 5 position rotary switch is used, in which case
the schmatic diagram represents the connections to the two poles of the
switch. One pole is wired so at the CCW most position it is connecting A to
B while in all other positions it is connecting C to B.
The other pole is wired so that the CCW most position is not connected to
anything. /2, /3 and /5 go to the next three succesive positions, and the
final position is not wired to anything (which gives /7).

If you can only get a 6 position switch, don't worry - it will simply mean
you have two /7 positions.



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