No audio at input jack tip?

[nunonaos]

Hello, i'm building a wampler velvet fuzz, this version:
http://effectslayouts.blogspot.pt/2016/08/wampler-velvet-fuzz.html

When i have the switch in Tight mode, i have sound, but in big mode, i don't.
The crazy thing is that i don't event have audio when probing at the input jack tip!

WTF? How is this possible?

Thanks

[GibsonGM]

A direct short to ground makes this possible...check your wiring...

[antonis]

Just to fill out the 50% remainder of Sir Mike's well said, check for wiring discontinuity..

[nunonaos]

thank you for the replies

one of these should happen, right?
1-have continuity from the tip of the jack to ground
2-not having continuity from the ground of the jack to the ground of the pedal

[GibsonGM]

thank you for the replies

one of these should happen, right?
1-have continuity from the tip of the jack to ground
2-not having continuity from the ground of the jack to the ground of the pedal

You should have continuity from the jack's tip all the way to the circuit board, through whatever switching you may have there.

You should NOT read a short to ground, or an open (Antonis...) in any switch position...signal has to make it to the PCB for the thing to work.

You SHOULD have continuity from the sleeve of the jack (the 'inner circle'...hole the barrel of your plug goes into...the small tip carries the signal) to ground, or the pedal won't work.  If you have it in one switch position, that is likely ok.

Welcome to the forum, by the way!

[nunonaos]

thank you for the replies

one of these should happen, right?
1-have continuity from the tip of the jack to ground
2-not having continuity from the ground of the jack to the ground of the pedal

You should have continuity from the jack's tip all the way to the circuit board, through whatever switching you may have there.

You should NOT read a short to ground, or an open (Antonis...) in any switch position...signal has to make it to the PCB for the thing to work.

You SHOULD have continuity from the sleeve of the jack (the 'inner circle'...hole the barrel of your plug goes into...the small tip carries the signal) to ground, or the pedal won't work.  If you have it in one switch position, that is likely ok.

Welcome to the forum, by the way!

Hello, I've been checking the forum for sometime but never registeredm thanks for the welcome

The thing is i acctually have continuity form the tip of the jack to the input of the board, in all switching positions...
And the sleeve of the jack also has continuity to ground...

I am missing something and it's killing me

[duck_arse]

both antonis and Gibson are too shy to ask, but I'm not - can you show us photos of what you have built? we might see some wiring funnies, cause it sounds like there is one there to see, somewhere.

also, welcome.

[nunonaos]

both antonis and Gibson are too shy to ask, but I'm not - can you show us photos of what you have built? we might see some wiring funnies, cause it sounds like there is one there to see, somewhere.

also, welcome.

yeah sure, i know it's my problem and i've made something stupid
i'll take some photos when i get home.

[GibsonGM]

Check out making an audio probe, too.  It will tell you where signal is or is not present, no measurements or other BS...in this case, it COULD tell you where your signal is going. 

http://www.diystompboxes.com/pedals/debug.html

Since it works in one mode, not the other, I am really thinking your switch wiring is the culprit, so a pic of that one would be great, yes!  Perhaps wired up to short to gnd in that position.   If you look, one sw. terminal goes to ground.   

[davent]

Check the fat/tight switch wiring. When you flip it you ground the pedal input. The jumpers insulated, not insulated and touching?



edit; What Mike said!

[nunonaos]

Check the fat/tight switch wiring. When you flip it you ground the pedal input. The jumpers insulated, not insulated and touching?



edit; What Mike said!

i am testing with an audio probe and have no signal at the input jack (when the switch is in big mode)

[nunonaos]

Check the fat/tight switch wiring. When you flip it you ground the pedal input. The jumpers insulated, not insulated and touching?



edit; What Mike said!

i'll take a pickture and post it here,
one of the jumpers is not insulated... but i checked continuity on the switch and nothing seems wrong... i'll check it again

[GibsonGM]

I agree, the error is likely there.   When one is "on", the other is grounded...easy to mess that up...

[antonis]

i am testing with an audio probe and have no signal at the input jack (when the switch is in big mode)

If switch comes after input jack (as usually..) you definately owe a beer (or more..) to Sir Mike...!!
(lost signal after jack declares unwanted grounding..)

Nevertheless, you also owe a picture of your wiring to our beloved visual down under fellow.. 

[nunonaos]

Here are a couple of pictures (before all wiring complete, with all wiring complete and a close-up of the big / tight switch)

Note: the bottom left footswitch is the effect on/off
The bottom right one is the dpdt in the schematic ( I am using a led so changed to a 3pdt)
The top switch is the big/tight

I checked the big / tight switch and everything is checking out... The input jack has continuity with board input and the sleeve has continuity with ground..
I checked for bridges or something in the switch and nothing... Any ideas
Thanks again

[Ben Lyman]

I guess if these jumpers were shorting, the input could be grounded but then I don't know how you could get signal in either mode. Probably have to have a bad switch and the jumpers shorting for that to happen

[Kipper4]

Are you using single strand wire for the input/output of the pcb?

[nunonaos]

Are you using single strand wire for the input/output of the pcb?

Yes.im using solid core wire for all connections.is that a problem?

Maybe the outter case of the switch is shorting against the DC jack or a pot?

Sent from my XT1562 using Tapatalk

[Kipper4]

No problem.
I guess there's continuity on all wires end to end.
It's just single core wire can snap easier than multi core.

Maybe not.

[nunonaos]

No problem.
I guess there's continuity on all wires end to end.
It's just single core wire can snap easier than multi core.

Maybe not.

Ye.that happens but less if it's cloth wire like this

Sent from my XT1562 using Tapatalk