Grounding Issue New Build - when plugged into the One Spot, all pedals off...

Started by frankie5fingers, March 23, 2012, 08:26:12 PM

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frankie5fingers

...
So I wired up the wah, using this configuration, only using a 2PDT switch.   No idea whether or not it wahs.  When I plug it into the 1 Spot, it turns the other pedals off, so clearly there's a grounding issue.  There were three tabs on the Nobiconn DC jack I described in my post above.  9V on PCB to center pin.  Non-center tab on the DC jack to one of the sleeve tabs on the input jack (according to one of the many possible ground configurations).  The other sleeve tab on the input jack to the sleeve tab of the output jack and gRound pad on the PCB and the center/left of the star 2DPT switch.   "In" from PCB to top left of switch.  Top right of switch to "out" on PCB.  Center right of switch to tip of output jack.  At this moment the tip of the inmput jack isn't attached to anything.  I did have it attached to the center/left of the switch, but that's where the sleeve was also attached; clearly it doesn't go there.  Obviously I have the switch wired incorrectly, which is, I beleieve, where I started this.  I can't post pic, this is a work computer and it prevents me from doing that.  Thanks

jkokura

Centre negative means that the 'centre pin' of the jack should go to ground. You may have wired your DC jack incorrectly.

There is no relation between where the LUGS are and where the pin inside the jack itself is. I use the term lug because that is what you're soldering to. The pin for a DC jack often can refer to the element inside the jack itself which connects to the internal central terminal inside the plug itself.

You don't need to attach ground to the switch at all. You have your switch almost wired correctly.

The top two lugs should go to the in and out of your PCB as mentioned. The middle two lugs should go to your jacks as mentioned. Your bottom two lugs should connect to each other.

If you googled "True bypass Wah Wiring diagram" you would get this come up: http://www.generalguitargadgets.com/diagrams/wah_847_lo_tb.gif

Jacob
JMK Pedals - Custom Pedal Creations
JMK PCBs *New Website*
pedal company - youtube - facebook - Used Pedals

jkokura

I think I need to understand what you understand 'pins' and 'lugs', because I'm not sure you and I are on the same page.

What do you mean when you say "pin"

Jacob
JMK Pedals - Custom Pedal Creations
JMK PCBs *New Website*
pedal company - youtube - facebook - Used Pedals

bangerang101

no, the center pin on the back of the 9v adapter jack is the ground lug and should be wired to all the other grounds, and the longer one of the two other lugs (outside one), goes to 9v on the board.

like this:





Owner of Luck Duck Pedals (LDP)

bangerang101

Your DC jacks 9v lug (outside lug) should only be wired to 9v on the circuit board. The center pin on the DC jack should be wired to all your other grounds (which is usually at the sleeve of the input jack)
Owner of Luck Duck Pedals (LDP)

jkokura

As I've said before, the centre pin of a DC Jack does not correspond with the centre tab, or lug, that you solder to.

If you look above, the diagram shows the centre 'pin' of the jack connecting to ground, as it should. But the centre 'tab' connects to the +9V pad on your PCB. Does that make sense?

As to your other questions and problems, perhaps if you took some good pictures we could see what you mean. Your problem points to a wiring error, so that's where to start.

Jacob
JMK Pedals - Custom Pedal Creations
JMK PCBs *New Website*
pedal company - youtube - facebook - Used Pedals

bangerang101

It's Ok, just take a deep breathe and follow me closely...

Based on your last post and the way you described your wiring, Ive found a few things that are probably causing your pedal not to work.

Ok first thing: you mentioned you were using a metal DC jack. You can't use a metal DC jack... w/ it mounted in the enclosure, your effectively shorting out the pedal,  + to -. If you must use a metal DC jack, you need to isolate the DC jack from the enclosure. Just find a way to have the DC jack's metal body, not be directly touching the enclosure (ie, wrap it in electrical tape, use rubber gromet, ect.)

This is why we use those round insulated plastic dc jacks in effects pedals. They work great, are pretty durable, and are fairly inexpensive and they isolate the 9v power from the enclosure... only thing is, you kind of have to order them online because local radioshacks or similar stores don't carry them.

Ok, so once you get that sorted out heres the next step:

wire the dc jacks CENTER LUG (gnd lug) to your star ground, at the input jacks SLEEVE LUG (inside lug) or at whatever point all your other grounds are all meeting.

now wire the +9v wire coming from your wah's circuit board to your DC jacks other, OUTSIDE LUG (+9v lug).

Now thats that for the DC jack. If you were to want to use a battery, the + (red wire) of the battery snap would go to a third lug on the DC jack (which I'm assuming you don't have becuase the metal DC jack your using only has two lugs right?) and the - (black wire) would go to the stereo input jacks RING lug (middle lug).

Anyway, if your not using a battery snap... just disregard that last sentence and don't use the third RING LUG (middle lug) on the Stereo input jack.

Ok so now your input and output jacks should be wired like this:

Input Jack - SLEEVE LUG (inside lug) on input jack should be your ground point. TIP LUG (far outside lug) on input jack should be wired to it's corresponding lug on your bypass (3pdt) switch.

Output Jack - SLEEVE LUG (inside lug) on ouput jack should be left open since it's being grounded to the enclosure. TIP LUG (far outside lug) should be wired to it's corresponding lug on your bypass (3pdt) switch.

Let me know if you have any other questions or if your confused about any of this.







Owner of Luck Duck Pedals (LDP)

frankie5fingers

THX banagrang.  I just found a post from the diystrat site that shows the specific metal Nobiconn jack and warns against using it as the plastic acts as an isolator.  Now I get it.  I actually did have it wired properly (except for needing to switch center for sleeve - neg for pos.) but it was shorting due to the metal jack.  This is clearly why I couldn't understand the problem.
I also have a spare plastic jack I'll install tomorrow with a couple of new jacks and that should do it.  Again, thanks to all for the patience, I'm sure you can see why it didn't make any sense - I had no idea why a metal jack would cause the issue.  Anyhow, thanks again.  Hopefully I won't need any more help on this one.  Frank

bangerang101

 Great! glad to help you out man... Weve all been there at some point, sometimes it just takes a proper explanation. :)

Let us know if you have any other problems.

Heres a little diagram you can use for the basic wiring of a pedal:

Owner of Luck Duck Pedals (LDP)

frankie5fingers

THX all.  Bangerang, great call on the metal jack.  I traded new for old, tossed the full metal jack and it works - solid and reliably.  Now I just need to get to the right combination of tweaks to get the output up and increase the depth of the wah.
Thanks much Jacob and bangarang.  I was about ready to add this to the box i keep the Rubick's Cube in.

Thanks again.

bangerang101

No, problem man... Always glad to help.

If the wah your building is based on the crybaby or vox wah (madbeans weener wah), you can increase output by reducing the input resistors value... I use a 47k resistor there for a boosted output volume.

Cheers!
Owner of Luck Duck Pedals (LDP)

frankie5fingers

Yup.  I put a 33K there, output's pretty much at unity. all good output-wise.  I socketed R2 and R4, C1, C5, Q1 and Q3.  Now I'm looking to expand the range a bit, and maybe widen tha "envelope" if I can.