regular pnp fuzz face has weird issue

[adapt]

not using the polarity inverter, just using a regular 9v plug but reversing the wires.

basically, my LED turns off when i tighten the nut on the input jack. i have the input jack sleeve connected to 9v+, so is a chassis ground and Q1 emitter, vol/fuzz lug 1, anode of 22uf electrolytic and anode of LED.


connected to ground is 33k resistor and 820 ohm resistor. seems like everything is wired correctly. but the LED shuts off when i tighten the input jack nut and my boss PSA-120 adapter blinks to indicate a ground issue.

Help?

[Travis]

Are you daisy chaining other pedals on the same power supply as the Fuzz Face?

Your description is hard to understand. Just post pics

[adapt]

my camera is broken on my phone or i would have. i am not daisy chaining anything, just using the boss PSA120 as a normal 9v adapter

positive lug on dc jack: chassis ground via lugged washer, input sleeve, Q1 emitter, fuzz 1, vol 1, anode of 22uf cap from fuzz 2, LED anode

negative lug on dc jack: 33k and 820 ohm resistor, switch lug on LED throw

this sounds right, yes? but for some reason when the sleeve/barrel of the input jack touches metal, the whole thing goes out with a "grounding issue"

it's driving me crazy

[Travis]

Where you connect -9V to the "switch throw" on the 3PDT are you then connecting -9V to ground as well?

Normally you would connect ground to the 3PDT for the switch and then use input grounded true bypass. The LED is normally powered via CLR to -9V

[adapt]

i have the switch wired up just like this:

http://fuzzcentral.ssguitar.com/faq/circuitwiringpnp.gif

and i meant switch pole, sorry for the confusion. it just blows me away that the LED's positive leg is connected to positive voltage that is literally connected to the enclosure itself, but the minute the positively grounded input jack gets screwed in, all hell breaks loose. LED off, indicator LED on power adapter indicates grounding issue. i'm kind of at my wits' end.

[Travis]

You're saying you have a positive voltage connected to the LED but we are talking about a pedal with a unipolar -9V power supply here so that's a red flag

The link that you gave and what you are describing are not the same, so unfortunately I'm having a had time pinpointing the issue for you without being able to see what you have done. It sounds like you have certainly shorted out the power supply, I am trying to help you figure out where but the info so far isn't too helpful

[adapt]

i don't know how better to describe it. what you're seeing in that picture is exactly how i have everything wired. there is no deviance. all of the ground points of a typical pedal are connected to +9v and all the "voltage" points are connected to ground.

i've used this wiring diagram before. many times. the power jack has two lugs. the positive one is connected to the anode of the LED. the cathode is connected to a CLR, which is connected to switch lug 1. switch lug 2 is connected to ground. the circuit is complete and works, but when i screw down the input jack's nut, everything shuts off.

my question is: why? the circuit is positive ground, why would it shit the bed when another positive wire touches ground? this is what i don't understand.

[Travis]

You keep saying +9V, ground, and -9V which does not make sense. You can have -9V and ground, you can have +9V and ground, but you don't have both at the same time with the power supply that you are using. It is not a bipolar supply.

Since there are no photos, it is important to give a correct description. The talk of +9V is adding a lot of confusion. I will say this, if you are measuring a positive voltage between ground and "9V", then you are shorting out the supply when you connect + to ground.

[Travis]

adapt wrote

i've used this wiring diagram before. many times. the power jack has two lugs. the positive one is connected to the anode of the LED. the cathode is connected to a CLR, which is connected to switch lug 1. switch lug 2 is connected to ground. the circuit is complete and works, but when i screw down the input jack's nut, everything shuts off.

I have to guess this is not what you meant to say because it wouldn't work this way. You're saying you connect both legs of the LED to + if we are to assume that ground is connected to +

What is "switch lug 2" connected to? Is what you are calling ground at that point + or - on the power jack?

[adapt]

as far as i've ever understood, PNP circuits require reverse polarity. 9V+ for all intents and purposes is "ground" in these circuits, and the normal ground wire is, for all intents and purposes, "-9V"

i've built plenty of PNP pedals and i've always just wired them up as if they were a negative-ground circuit, then just switched the lugs on the power jack. is that not how this works?

[adapt]

it needs to be stressed that I've checked my wiring against the diagram i posted earlier a bunch of times and it is the exact same.

in the schematic i posted, "negative" is connected to the 33k and 470R

also in the schematic, "positive" is connected to Q1 emitter, 1m resistor from Q1 base, input sleeve, volume 1, fuzz 1 and 22uf electrolytic +.

this is all correct. also in the schematic, "positive" is connected to LED anode, with LED cathode connected to CLR, then connected to switch lug 7. "negative" is connected to switch lug 8 (i'm using 1 and 2, respectively). with that said, everything is wired up correctly. but when i run a wire from "positive" to the input sleeve, as it states in the schematic to do, everything dies.

[Travis]

I'm just going on what you have posted and trying to sift through the conflicting information

If we are to assume the wiring is correct then it sounds like you might have -9V shorted to the chassis. In it's installed state in the enclosure, do you have continuity between -9V and the chassis?

If -9V is shorted to the chassis then that would explain why it shorts the power supply when you connect the chassis to ground

[adapt]

i will try when i get home. thank you for being patient with my no-camera-havin' ass.

[adapt]

a big THANK YOU to travis for putting up with my inane BS. minuscule solder bridge, everything is sorted <3

[scimitar]

Not sure if this is solved but if not - if you are powering by a power supply instead of a battery then you cannot connect the same power supply to any other effect (negative ground) unless the power outputs are fully isolated, otherwise your cables connecting your effects together will connect the positive ground of one pedal to the negative of another, effectively shorting the supply.