Cornish Stereo output/Input

[boidek]

Hi all,

First, This is my first post here so hello everyone

my question is:
I noticed Pete Cornish is using stereo inputs and outputs on his pedals and he also grounds each input/output to the enclosure.
1. Any Idea why stereo and not the regular mono?
2. why grounding the input/output?
3. Also noticed he uses 2 resistors and a ceramic cap on the output. a. any idea why? b. any schematics on how he uses it?
4. Can anyone post an off-board drawing of his pedals?

[PokeyPete]

Do a search for "Cornish G2". I believe that every question that you asked is answered on that very interesting thread.
There is a terrific, detailed schematic included there by Dirk Hendrik. If you can read a schematic, it will answer most,
if not all, of your questions. If you still need answers after that, then ask away!

[boidek]

Thanks!
I tried following all (too much read )

According to what I understand, the following is the wiring diagram sketch.
Just couldn't understand where and how to connect the Resistors/Cap to the output.
Also, need help with how to connect the input.
http://boidek.wix.com/cij-62-reissue

Can someone complete the drawing I made?

[boidek]

this is the incomplete sketch:


can someone complete it?

[boidek]

No one???

[Nocentelli]

this is the incomplete sketch:

[butchered=image]taken from beavis[/image]

can someone complete it?

No one???

The way you've drawn it, your footswitch connects the circuit board input to either the output, or through an LED and a 2k2 resistor to +9v. Can I politely suggest you study and get to grips with plain old 3PDT true bypass wiring, then have a look at Cornish's.

1. Any Idea why stereo and not the regular mono?

Cheap, isolated stereo plastic jacks bought in bulk?

2. why grounding the input/output?

Cheap, isolated stereo plastic jacks bought in bulk?

3. Also noticed he uses 2 resistors and a ceramic cap on the output. a. any idea why?

Which pedals? Got a picture, link, anything?



This is on the first page of the G2 thread, I see two resistors on one jack, can't read the values on my phone. One appears to link the two input lugs of the switching jack together, the other is probably an output pull-down resistor[/url]

As for a cap:

It's a fairly common way (especially in the RF engineering world) to ground a panel. It gives DC isolation, but the screening properties of the case are preserved.

Wouldn't that mean that the cap would always been in the signal path, regardless of whether or not the G2 was bypassed?

Yes, but if you look at the schematic, you see that the sleeve connection of the output jack still connects directly to the chassis ground via the ground path of the circuit board that it's connected to. The output jack connects to the chassis via the cap, make sure the chassis screens the signal sufficiently, but the cap is used to make sure there are no DC ground loops caused by any difference in potential which may exist between the input and output jack grounds.

At least, I think that's what is going on!

...is on page 4 of the thread.

4. Can anyone post an off-board drawing of his pedals?

Which pedals? The G2 in the photo above has an input board with the buffer: The input goes direct to the daughter board, then on to the switch: The switch sends it on to the main circuit board (a buffered Big Muff ) or bypasses it to the output, wired in the normal way i presume.

[edit]Actually, just look at the schematic, it's all there.... 50k resistor to ground on the output and a 0 ohm resistor across the output tip lugs - I'm never going to get those ten minutes back...[/edit]

[boidek]

Sorry for your 10min, don't know what was over me when drawing this! Must have drank before
Yes, I am referring to the G-2 schematics when drawing this.
Anyways, this should be much more accurate (the 3pdt was taken from one of the sites linked here in this forum).
But again I have trouble with the Stereo Jacks (don't know which leg is S/T/R), So If someone can help out it would be much appreciated!

[Nocentelli]

Yeah, that's much better. As for the T/R/S, if you imagine the end of each jack that is next to the in/out label is the end of the jack that sticks through the enclosure, your out jack is drawn correctly: The pair of lugs nearest the label is sleeve/ground via the cap, the middle pair is ring, and the bottom pair (that you've connected together with the 100r resistor) is tip, connected to ground via the 50k - That jack is drawn correctly. The input jack just needs the chassis ground connection moving from the tip lug (where you have it now) to the lug nearest the "in" label. Note that you do not need those plastic switching stereo jacks with six lugs to wire up a pedal Cornish-style, just a standard single mono jack (two lug) for output and a standard stereo input jack (for battery switching) would work just as well, Hope this helps.

[boidek]

Thanks!
I think I got it?

BTY, the stereo jacks for some reason are less expensive

[Nocentelli]

Thanks!
I think I got it?

I assume the battery negative is only connected to input ring (and nothing else is) to stop current draw when the input is connected, but other than that it looks good to me. Just make sure the switched input connection is the one that is grounded - You can easily tell just by looking at the jack socket and pushing a plug in to see which one is disconnected: this is the one to earth, and use the permanently connected lug to circuit input.

This is actually a neat idea for grounding the input when a cable is disconnected, I'd not seen it before: My pedals aren't particularly noisy if a cable is disconnected, but i suppose don't play through a massive rig at volume - Might be useful.