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Clarification on DC/battery wiring

Started by madbean, May 30, 2010, 07:01:08 PM

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madbean

In the wiring diagrams for the projects I use a certain labeling convention for the DC jacks and battery. It's come to my attention that this is confusing some people, so I will try to clarify.

Standard Boss type plugs deliver a center negative tip. In my diagrams I've labeled the DC jacks as +9v on the "tip". This is probably not the best way to do it. To me, I've always associated the "tip" of the actual jack as delivering +9v, which is probably just a little meme I constructed to avoid confusing myself. However, using this convention could make it appear as though connecting the jacks/battery as I picture it would lead to a short. This is not the case: the diagrams are correct, but the naming is kinda bad.

For example:


In this example, I've labeled the DC Jack as having a 'tip', 'ring' and 'sleeve'. The 'tip' delivers +9v to the board and the sleeve acts as ground. The 'ring' is connected to +9v on the battery, and the negative lead of the battery is connected to the ring on the input jack. This set-up delivers +9v to the board, even though it is confusing on my part to label the jack as the 'tip'. When the 2.1mm plug is inserted, the power supply operates to deliver the necessary voltage to the board. When the plug is removed, the battery delivers the power. If the input jack is unplugged, the battery is then disconnected.

To clarify further, please refer to the diagram of the DC jack listed on the smallbear website.
http://www.smallbearelec.com/Detail.bok?no=93

In Steve's diagram, he labels the tabs "To battery+", "To board+", and "To board - and battery -". The correspondence is as follows:

Me ----- Steve

"Tip" = "To board+"
"Ring" "To battery+"
"Sleeve" = "To board - and battery -"

Hopefully this resolves the issue!

gtr2

1776 EFFECTS STORE     
Contract PCB designer

luke75

Hello,

First of, Thank you a lot for your help that is greatly appreciated.
I have 2 questions regarding the dark side project :
- reading the wiring diagram, there is no 9V battery in the dc wiring diagram : if i want to build this project and use a 9V battery, what sould be the correct wiring?
- Any suggestions for the 1N5401 substitution?

Thank you again.

Have a good day.

oldhousescott

1N4001 should work as a substitute for 1N5401 in this application. I've attached a marked up drawing showing the addition of the battery clip.

[attachment deleted by admin]

luke75

Thank you very much !

I'll try it as soon as possible.

frugalamps

Hi- I am trying not to be too dense hear.  If indeed the classic boss power supply and most others- deliver a -9V on the tip of their plug then how is it magically changed to +9V at the tip of your DC jack diagram?  I am thinking the sleeve would be the +9v source since the center is -9V?  Or am I confusing positve and negative somehow.
   Also, if you order the smallbear metal bodied dc jack instead of the plastic one, will it work or do you have to isolate it from the box?

pandadandan

Quote from: frugalamps on July 02, 2010, 12:39:30 AM
Hi- I am trying not to be too dense hear.  If indeed the classic boss power supply and most others- deliver a -9V on the tip of their plug then how is it magically changed to +9V at the tip of your DC jack diagram?  I am thinking the sleeve would be the +9v source since the center is -9V?  Or am I confusing positve and negative somehow.
   Also, if you order the smallbear metal bodied dc jack instead of the plastic one, will it work or do you have to isolate it from the box?

It's not -9v at the tip.  It's 0v. 
The sleeve is +9v.

frugalamps

OK- the tip is 0 volts.  so the diagram shows +9 volts coming from the battery to the ring of the dc jack.  When a plug is inserted to the stereo switch, the battery is taken out of the circuit and the pedal is supposed to get its +9v now from the tip of the DC jack....but we just learned the tip was 0 volts, not +9 volts.  Should the +9 be coming from the sleeve of the DC jack and going to the pedal circuit and the tip should be going to ground instead of the sleeve?

madbean

Yes, this was the confusion over how I labeled the DC jack. Take a look again at the post above: the 'tip' 'ring' and 'sleeve' naming was purely made up by me. It is not technically correct, I suppose, but just the way I thought about it.

The plug delivers 0v @ the tip, and sleeve at +9v. The jack itself is hooked up as the post describes. Just ignore what I have labeled as tip, ring and sleeve on the jack and the confusion will relent :)

For further clarification, take a look at the doc for the new 'Cherrybomb':
http://www.madbeanpedals.com/projects/Cherrybomb/docs/Cherrybomb_ver1.pdf

Here, I have created a new diagram for the DC jack to clear this up. I'll be using this in all the wiring diagrams going forward. Sorry this is troubling you. I can assure you that if you follow the wiring diagram, it works properly.