madbeanpedals::forum

Projects => Tech Help - Projects Page => Topic started by: wretched on November 06, 2013, 02:42:28 PM

Title: PNP Fuzz power
Post by: wretched on November 06, 2013, 02:42:28 PM
Probably a dumb question, but could I just change the polarity on the DC plug for a PNP fuzz pedal? Like connect the negative to the positive on the jack?

I am guessing it will create problems seeing it seems like the easiest way.
Title: Re: PNP Fuzz power
Post by: garfo on November 21, 2013, 11:11:48 PM
I'm pretty sure you can do that.You'll have to sacrifice that power transformer though.
Title: Re: PNP Fuzz power
Post by: RobA on November 21, 2013, 11:28:55 PM
You can only do this if the transformer power output is isolated. If you use a separate transformer for the one pedal or if your transformer has isolated taps it will work. If the taps aren't isolated, doing this will cause a dead short from the power rail to ground. You would also need to mark the jacks well and remember what you did. The problem is that everyone is really used to one standard with the 2.1mm DC jacks. MAcking a mistake and plugging into the wrong power supply is just way too easy.

My personal preference is to do something to generate the negative rail in the pedal.
Title: Re: PNP Fuzz power
Post by: selfdestroyer on November 22, 2013, 12:08:54 AM
I tired this with a 1Spot I had years ago and like RobA says

QuoteIf the taps aren't isolated, doing this will cause a dead short from the power rail to ground.

No worky.
Title: Re: PNP Fuzz power
Post by: davent on November 22, 2013, 12:57:25 AM
My approach is, from what i've measured, my positive ground pedals with high intensity LED's draw such a small amount of current, batteries seem to last forever so i just go with a battery.

You could add a charge pump circuit to your pedal such as Madbean's  Road Rage and then you could you add it to your string of powered pedals with no worries over the mixed grounds.