Cgs synth

I just want to preface this by stating that I have 0 electronics
experience other than soldering my own cables.

I'm just about done with my first DIY module from the CGS, the simple
wave folder. I'm just waiting for a Semi from mouser and all
components will be soldered to the PCB.

I can't seem to find a straight foward explanantion of audio jacks,
specifically 3.5 mm jacks. I need to figure out exactly which patch
point on the jack is the input, output and ground. I don't have a
schematic for any of the other modules that use 3.5 jacks, so I can't
logically figure this one out. Can anyone point me out to a simplified
explanation or book or anything that might help. I hope this list
believes in the no stupid questions matra, this is certainly one.

Also, according to the schematic the input going through the 100k pot
needs to grounded. I think that means I need to wire the ground output
of the pot to the "0V" in on the pcb thats between the 2N3906 and 15k
resistor. Can someone verify that this thinking is correct?

I'm probably going to have more questions once i get the module all
wired up.

Thanks Alot,

Don

>
> I can't seem to find a straight foward explanantion of audio jacks,
> specifically 3.5 mm jacks. I need to figure out exactly which patch
> point on the jack is the input, output and ground. I don't have a
> schematic for any of the other modules that use 3.5 jacks, so I

can't

> logically figure this one out. Can anyone point me out to a

simplified

> explanation or book or anything that might help. I hope this list
> believes in the no stupid questions matra, this is certainly one.

Oh man, Don! If I didn't ask stupid questions, I'd be nowhere!

If you have a DVM or any kind of continuity tester (light bulb,
wire, battery) and a 3.5mm plug, you will be able to see which lug
on the jack correlates with which lug on the plug. If your jacks
are the open type, you will be able to see which lug is part of
which element - the sleeve (ground), the tip (signal), and the
normally-closed contact with the tip (for sending the signal to
another point when there is no plug inserted).

>
> Also, according to the schematic the input going through the 100k

pot

> needs to grounded. I think that means I need to wire the ground

output

> of the pot to the "0V" in on the pcb thats between the 2N3906 and

15k

> resistor. Can someone verify that this thinking is correct?

You are correct, sir! Zero volts is our reference (some call it
ground) and return current path. You're dividing the signal voltage
between the input stage and zero volts with the pot acting as a
voltage divider.

>
> I'm probably going to have more questions once i get the module all
> wired up.

Good. Read my thread about my little VCO woes. We all hit snags
from time to time. Help when you're able, ask when you need help.

>
> Thanks Alot,
>
> Don

You're welcome, and welcome to electronics!

Chub

> I'm just about done with my first DIY module from the CGS, the simple
> wave folder. I'm just waiting for a Semi from mouser and all
> components will be soldered to the PCB.

Welcome aboard!

> I can't seem to find a straight foward explanantion of audio jacks,
> specifically 3.5 mm jacks. I need to figure out exactly which patch
> point on the jack is the input, output and ground.

The easiest way to answer this question is to figure it out yourself. :-) In
all seriousness, there is more than one kind of jack out there, so you'll
have to examine your own particular jacks to figure out what's what. Stick
a patch cable into a bare jack and use a continuity tester of some sort
(like an ohm meter or continuity beeper on a DMM) to figure out which lug on
the jack connects to the ground of the cable. Then figure out which one
connects to the tip of the cable. The remaining lug is the "NC" lug, or
Normally Closed lug. This lug connects to the lug for the tip conductor when
no cable is inserted in the jack, but is disconnected when a cable is
inserted. In the case of the Simple Wave Folder, this lug is not used.

> Also, according to the schematic the input going through the 100k pot
> needs to grounded. I think that means I need to wire the ground output
> of the pot to the "0V" in on the pcb thats between the 2N3906 and 15k
> resistor. Can someone verify that this thinking is correct?

It's a little difficult to make out from the image on Ken's website, but
yes, this looks (and sounds) to be correct.

Have fun!

--Adam

Thanks for the help. It all makesa little more sense now.

-DM