PNP FUZZ FACE BUILD HELP

[seagurt]

Hello all.

I recently purchased sone PNP germanium Transistors from the good folks at small bear. It is my understanding that this is supposed to be a negative ground build, and so I ordered some PNP Germanium Transistors (PNP texas instrument 2g308). ,the first issue arose as I cant find any datasheets on the pins for the Collector Emitter and Base. From what I have found, it should be CBE as pins 1,2, and 3.

The second issue (or confusion) arose from getting the diagram from small bear as it being a negative ground (as opposed to the positive)and so I am left scratching my head. All indications for this circuit indicate it should be positive ground. I have bread boarded the crurcuit using both positive and negative layouts, switced electrolytic positives and negatives to test both circuits, and even used non polarized capacitors, and sockets to switch out positive and negative polarities on components. All of my caps are tested, as well as resistors.

I am looking for any type of help regarding this build, as it should be simple, but I am left dumbstruck. I have tried to upload pics, but cant figure out how to do so... :/

Please feel free to ask any questions you may have, and I will reply as best as I can.

I am looking forward to getting this simple circuit built, and learning what the issue is. I will keep trying different layouts until I get it right.

[Quackzed]

it's a confusing situation made worse by different approaches to naming things. easiest way to look at it is this: don't worry about whats called ground or positive ground vs. negative ground etc, untill you hook up the battery or power supply... the explanation is this : if you look at the above schematic, you'll notice that the + side of the battery is connected to ground. so it IS a positive ground circuit if it uses pnp transistors.
just ignore that, check your pinout of your transistors, google 'transistor number' and 'pinout' and make sure each leg is going where it should, then make sure all your grounds are connected to each other.check the polarized caps are oriented right according to the above picture, then when its time to hook up the battery, double check the schematic and connect the +side of the batt to ground, and the negative side to the intersection of the 470 and 33k resistors (actual values of those resistors may vary a bit.)

some transistors legs are different than the pic below, so look up your specific transistors pinout. 

[Hatredman]

I shall disagree with the "just ignore that" statement, because the OP may want to use this pedal with other negative ground pedals AND use the same external PSU on all of them. Trying to do so may result in short circuits, loss and a lot of crying.


Sent from my iPoor using Tapatalk - now Free because I'm poor

[GibsonGM]

"Until you know what's up with positive ground circuits, always power them from a battery"   

[smallbearelec]

Please e-mail us at smallbearelec@ix.netcom.com. We will do our best to get you going.

[seagurt]

I shall disagree with the "just ignore that" statement, because the OP may want to use this pedal with other negative ground pedals AND use the same external PSU on all of them. Trying to do so may result in short circuits, loss and a lot of crying.

Thank you for that statement. I am using the pedal solely with a battery, no DC jack.

"Until you know what's up with positive ground circuits, always power them from a battery"   

All my research told me the same. And thank you for your input. Helpful info is always appreciated.

I will email the kind folks at small bear.

Thank you for all your expertise. The people here are always great.

[GibsonGM]

Thank you for all your expertise. The people here are always great.

That is because we were once all new like you, and because down the line, you will be helping new people, too!

[duck_arse]

seagurt, seahear:

http://www.diystompboxes.com/smfforum/index.php?topic=113550.0