Author Topic: Switching power jack questions (-9v circuit)  (Read 208 times)

eightsevenzero

Switching power jack questions (-9v circuit)
« on: January 14, 2022, 02:44:26 PM »
I'm working on a -9v fuzz and have one of those switching power jacks that cuts the battery when a power plug is inserted. Would it be possible to wire the battery to center terminal in reverse fashion for -9v and then the power jack lug for +9v to power an inverter board? So essentially the jack has both -9v and +9v on it, but it cuts the battery when the power plug is inserted. I've attached a crude diagram below. Thanks


Kevin Mitchell

Re: Switching power jack questions (-9v circuit)
« Reply #1 on: January 14, 2022, 03:23:18 PM »
It depends. Are you looking for a light & smoke show?
If there's an inverter why would you want to wire anything in reverse? Wire it as you normally would. Otherwise you're going to damage components.
  • SUPPORTER
I'm archiving all of my DIYLC work for the home-etchers - Project Layouts & Templates

eightsevenzero

Re: Switching power jack questions (-9v circuit)
« Reply #2 on: January 14, 2022, 04:41:27 PM »
Not sure you're understanding which I'm sure is because of my explanation. The circuit is PNP -9v. It needs -9v power from both options, battery and power jack. The power jack is handled with an inverter, the battery would need to be wired to supply -9v power. The inverter is required because I'm preparing it for use with non-isolated power supplies.

idy

Re: Switching power jack questions (-9v circuit)
« Reply #3 on: January 14, 2022, 05:37:13 PM »
Kind of interesting thought process: to have the battery with no charge pump inverter, or DC jack with inverter. I don't think your diagram will work, not sure how to swing it.

All of the configurations I have seen just put the battery through the invertor too.

eightsevenzero

Re: Switching power jack questions (-9v circuit)
« Reply #4 on: January 14, 2022, 07:04:29 PM »
Kind of interesting thought process: to have the battery with no charge pump inverter, or DC jack with inverter. I don't think your diagram will work, not sure how to swing it.

All of the configurations I have seen just put the battery through the invertor too.

Yeah, I suppose that's the easiest solution, I just figured I'd try to give the "purist" option of running the circuit direct from the battery, I'm also not sure how much of a draw it would be to power the inverter as well.

FiveseveN

Re: Switching power jack questions (-9v circuit)
« Reply #5 on: January 15, 2022, 02:37:38 AM »
Does this inverter have a name? A datasheet that mentions such things?
Does the circuit sound better when oriented to magnetic north under a pyramid?

duck_arse

Re: Switching power jack questions (-9v circuit)
« Reply #6 on: January 15, 2022, 08:59:46 AM »
you could diode OR gate the output of the invertor and the battery, so when no DC plug, no invertor out, so the batter will win the OR and supply the circuit. would not require any switching work from the DC socket, either.
imps are sold

eightsevenzero

Re: Switching power jack questions (-9v circuit)
« Reply #7 on: January 15, 2022, 10:29:56 AM »
Does this inverter have a name? A datasheet that mentions such things?

Here’s a link to the inverter:

https://tagboardeffects.blogspot.com/2012/05/negative-voltage-inverter.html?m=1

Kevin Mitchell

Re: Switching power jack questions (-9v circuit)
« Reply #8 on: January 17, 2022, 03:08:15 PM »
Not sure you're understanding which I'm sure is because of my explanation. The circuit is PNP -9v. It needs -9v power from both options, battery and power jack. The power jack is handled with an inverter, the battery would need to be wired to supply -9v power. The inverter is required because I'm preparing it for use with non-isolated power supplies.
I'm not sure what's the confusion part. I thought I understood?   :icon_confused:
What I mean is you should treat everything (battery & DC jack) as positive polarity and just wire up the inverter -9v supply to the effect circuit - which you would be doing anyways. The way you want to do it will not work and will create problems that otherwise wouldn't exist.

Your DC jack handles the switching and expects positive polarity. Your inverter circuit creates the -9v supply and also expects positive polarity.

Your drawing shows the battery's positive terminal going to the ground of the inverter and without a DC plug connected the ground terminal would go to the +9v side of the inverter. That's one way to blow up your chip along with any polarized capacitors on that little board.

My point is you've made a problem and an incorrect way to handle the problem. So backtracking may give you clearity.
Or am I really not understanding?  :icon_neutral:

If what you mean to do is bypass the inverter board for when using a battery, then the DC jack switching will not be an adequate, failsafe solution for this.
« Last Edit: January 17, 2022, 04:17:08 PM by Kevin Mitchell »
  • SUPPORTER
I'm archiving all of my DIYLC work for the home-etchers - Project Layouts & Templates