Doubts and safety checks for building first pedal

[iommimonkey]

Hellooo Internet so nice to see you,

So after stocking up I'm building my first pedal. I decided to go with the MXRDIST+ since I saw it in tonepad labeled as a beginner one. For background, I've done some electronics at university but not much, and I've worked with digital boards like STM32F7 but I never added anything else to the board.

I used this schematic to build the pedal in a protoboard: http://tonepad.com/getFileInfo.asp?id=115


Regarding the offboard wiring I've been reading in a lot of places and I see there are several approaches on how to do it, and I'm a bit confused for using stereo for the input and mono for the outpit since I guess I can have short circuits depending if I use a stereo or mono cable (I have one stereo cable for some reason).

For the sake of having the first pedal done and keep my moral up on this, I decided to learn about the reasoning behind that in parallel with making a real pedal, so I decided to go no brainer with the tonepad offboard wiring schematic (http://tonepad.com/getFileInfo.asp?id=76 PAGE 5, OFFBOARD WIRING 5) because I'm using their schematics for the pedal as well, and just forget about everything else by now.





My concern is that I'm going to be connecting stuff to the wall and phew, this is a lot of volts, and there's this wall adapter in the schematic so I just wanted to double check that everything should be safe if I mess something up even with the wiring using those schematics, or I touch something when it's on. I might sound paranoid on this but I don't know if I can die of making a pedal (believe me, I can be very dumb). I don't know if it's possible to somehow pushing a lot of current into the guitar that can be unsafe.

As a side note, I'm also confused because I have mono jacks with 3 pins but the schematics show only two, so I don't know what the third one is for, but this is another topic.

See you!

[kaycee]

If you have a proper plug in wall adapter power supply, then you should have little to worry about. It will step the wall voltage down to 9 volts, which tickles a bit, but won't stop your pacemaker.

Most pedals incorporate some voltage protection measures, often a simple diode which will blow or block over or wrong polarity voltage going in.

Yes, if you wire it wrong or get a short, you can get a nasty little burn off of a hot IC chip, and they can set light too, or at least go up in a puff of smoke.

If you are that worried, run your first project off of a battery only, which will still do the above.

The jacks with 3 tangs are tip, sleeve and ring connections. The ring is used to switch on the power when a jack is inserted, completing the powers path to ground. Sleeve is your ground connection, tip your signal. Usually you will have one jack with two tangs, and one with 3 (for input), but you can use the 3 for both and not use the ring on the out.

Relax and enjoy it.

[rockola]

My concern is that I'm going to be connecting stuff to the wall and phew, this is a lot of volts, and there's this wall adapter in the schematic so I just wanted to double check that everything should be safe if I mess something up even with the wiring using those schematics, or I touch something when it's on. I might sound paranoid on this but I don't know if I can die of making a pedal (believe me, I can be very dumb). I don't know if it's possible to somehow pushing a lot of current into the guitar that can be unsafe.

It pays to be careful for sure.

- Don't grab the hot end of a soldering iron, or poke yourself or anything flammable with it
- Don't breathe the soldering fumes; I use a computer fan to which I've attached an active carbon filter to pull the fumes away from my face
- Wear safety glasses when clipping wire
- Don't eat the yellow snow (OK, that one is perhaps not pedal-related)

Use a 9V battery for testing; it'll be safe even if you short it. A 9V wall wart likewise won't kill you, but as with anything else with a wall plug, toss it if it breaks, even a little.

[iommimonkey]

The jacks with 3 tangs are tip, sleeve and ring connections. The ring is used to switch on the power when a jack is inserted, completing the powers path to ground. Sleeve is your ground connection, tip your signal. Usually you will have one jack with two tangs, and one with 3 (for input), but you can use the 3 for both and not use the ring on the out.

I understood that mono jacks have Tip and Sleeve, and stereo jacks have Ring, Tip and Sleeve, and I have one mono jack with 3 pings, but doesn't have the big ring ping though.

Relax and enjoy it.

Thanks!!

[duck_arse]

iommimonkey, welcome to the forum.

what you show appears to be a switched jack [switch is normally closed, and opens when a plug is inserted], which is different to a stereo jack. you just want the BIG tip dinger lug, for signal/hot and the sleeve lug, for ground/common. don't sweat the mains, the plug pack will isolate you, unless you do something really stupid.

I don't think we have any forum members that stupid.

[edit:]

I don't know what the third one is for, but this is another topic.

put it all in this thread, where we know to find you. your second build can be a second thread. also, not posting the schems to go with your questions will cause friction and start ructions here. tonepad has never complained about the postings here - he is a member here, as are most of the other pedal site people.

[anotherjim]

Could be a grounding jack. Typically used on guitar amplifier channel inputs. The switch lug is wired to the input ground so the tip contact will be shorted to ground by it. When you plug in, the switch opens, removes the ground and allows signal in via the tip contact. You want the input grounded when it's not used to stop the amp picking up hum -which it will. An amp that's noisy when nothing is plugged in may well have a dirty tip grounding contact.

[iommimonkey]

Thanks for your answers! I edited the post to include images then if it's not an issue. I'm going to be posting issues here then.

So regarding the mono jack with 3 pins, should I connect the third pin to any place?

[antonis]