Fuzz face

[Coda-effects]

Hello !
I am currently finishing a fuzz face following Scruffie's layout ( http://music.codydeschenes.com/wp-content/uploads/2014/08/Fuzzface-Scruffie-TRANSFER.pdf ), but I have a stupid question : what does the "J Sw" output / input ? stands for ?
This is the last solder I have to make, and I am quite impatient to test it (I even got old NKT275 for it !)

Thank you for your help !

benoit

[AntKnee]

Is there a schematic for this?

[TGP39]

I'm pretty sure that is where you would put one leg of your LED.  The other leg would attach to your foot switch.

Steve.

[Coda-effects]

Hum, the trouble is that I already wired the LED to the switch... Should I connect it to the ground ? For now the pedal is not working...

[m-Kresol]

Hum, the trouble is that I already wired the LED to the switch... Should I connect it to the ground ? For now the pedal is not working...

No, don't connect it to GND. I doubt that it is for the LED, as it is connected to a transistor via a resistor and the latter is not for polarity protection as there is a diode to ground before that. Even if the pad was for the LED, connecting it to ground wouldn't help.

[Coda-effects]

Hum, I do not really get what is the purpose of the transistor... For me a negative voltage inverter would just be as simple as that :


I will check a bit the values of the current I get at different parts of the circuit... But I am a bit lost here... Thank for your help

[Stomptown]

Is I maybe being used for polarity protection???

[m-Kresol]

Is I maybe being used for polarity protection???

there already is a 1N400x diode for polarity protection on it... I'll send scruffie a PM with a link to this thread. I guess, he didn't see it

[Coda-effects]

Thanks ! 

[Stomptown]

Is I maybe being used for polarity protection???

there already is a 1N400x diode for polarity protection on it... I'll send scruffie a PM with a link to this thread. I guess, he didn't see it

Yeah, I saw that but thought that this may be a more complex was of doing it or something.  If you look at the Madbean PNP Rangemaster with built-in voltage inverter, he uses a MOSFET for polarity protection (RG Keen suggestion) so I thought maybe this was something similar but different?

[Scruffie]

http://www.geofex.com/circuits/+9_to_-9.htm

[Coda-effects]

http://www.geofex.com/circuits/+9_to_-9.htm

Thanks ! I will read it carefuly.

[m-Kresol]

Thanks Scruffie!

Ok, all makes sense now (more or less at least). The 2N3904 transistor is used to basically "separate" power and signal grounds to eliminate noise. So, actually you do have to connect that pad to ground after all (via the ring connector of a stereo jack using a mono cable) It will give you a base-emitter current on the transistor which itself switch the 9V on the collector-emitter, thus powering your effect.

[Coda-effects]

Ok I got it !
Very clever system, works like a charm !
Unfortunately, it was not really useful in my case, as I do not have enough space to put a 9V battery in my build (these 1590B enclosure are quite small after all... )
Anyway, hopefuly it will be soon in the builds reports section !