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DIY Stompboxes => Building your own stompbox => Topic started by: igor12 on January 26, 2009, 09:16:45 PM

Title: DC power jack--center pin - or + ?
Post by: igor12 on January 26, 2009, 09:16:45 PM
OK, I'm working on a new design that I dream of selling millions of.  I know most effects have center pin -.  This always seemed counter intuitive and makes things harderand dangerous,  cause you have a higher chance of shorting to chassis which is also ground. Do companies do this just so you buy their wallwarts? I can't decide which way to go because I'd like to maintain compatabilty with boss, ibanez and MXR supplies.  I guess their paint insulates the chassis well enough.
Title: Re: DC power jack--center pin - or + ?
Post by: Ripthorn on January 26, 2009, 09:20:08 PM
As long as your pedal has reverse polarity protection, it shouldn't damage much if anything.  Also, center negative is very common in pedals, most people should know about it.  I say go with what the industry does.
Title: Re: DC power jack--center pin - or + ?
Post by: runmikeyrun on January 26, 2009, 09:31:46 PM
that or put in a polarity reversing switch, but then you'll get stupid people who bump the switch or something... yeah, bad idea.  Just go with center -.  I hate DOD with their stupid 1/8" plugs, what a dumb idea.
Title: Re: DC power jack--center pin - or + ?
Post by: petemoore on January 26, 2009, 09:39:52 PM
  companies keep people like us.
 They try to keep us happy.
 Unfortunately the way things turned out is...counter intuitive to not burning stuff up when it comes to + and - and AC and DC all sharing the same type of jacks, the chances for things to go wrong in such scenarios is great.
 And I wanted to have my company which makes effects for me put different jacks than AC, DC wrong polarity or voltage could connect to.
 In the end, Guessepi [my imaginary friend] and I settled on the DC jacks just like everyone else, AC/DC and people with polarity reversal probles do, the potential for voltage and damage is unknown with this system because I've been lucky [I just plug in the IEC to the PPII and go.
 The one best simple reason our company [me] chose DC jacks is probably the same reason other companies do, except I did have the option to opt out of the 'danger jack' scenario [for me that's less of a danger, but ya never know if it's off the PB and...]:
 The reason is:
 Most of the power supplies follow the same reasoning.
 They have plugs fitted that fit the DC jacks described above.
 When discussing "DC JAcks", DC Jacks is short for "Danger Connection Jack"...sort of the same thing with the plug side too "Danger Connection Plug".
 The only real danger most of the time is to pedals and PS's.
 All the 9vNpN effects my company made are wired with Neg. Gnd. / Negative barrel, I used some metal DCJacks.
Title: Re: DC power jack--center pin - or + ?
Post by: German on January 26, 2009, 10:51:35 PM
Two diodes.. + one switch will help much.
Title: Re: DC power jack--center pin - or + ?
Post by: R.G. on January 26, 2009, 11:02:18 PM
Quoting myself from only two days ago:

QuoteIn the beginning, there was Boss, and they did bring forth on the earth an adapter for powering pedals.

And they did find that having the center negative did make their own circuits easier to manufacture. And they said "It is good."

From thence forth, all adapters were made by Boss, and they did wax great upon the earth, and prospered in number into the uncountable millions.

And others did detect the sickly-sweet smell of money in their nostrils and did say "If Boss shall make adapters which have the center negative, so shall we." And it was so.

And they did bring forth adapters of many and various sizes and shapes, but none of them had center positive. This caused vexation and consternation in the minds of those who owned positive-ground pedals, because lo, these pedals did require the positive of the power supply connected to ground. But there was already in the earth millions of Boss pedals requiring center negative, and also Ibanez took up the center negative, and other makers of millions of pedals. And so the owners of positive ground pedals were smitten with great wrath, for their pedals would not play well with the minions of the Great Boss.

And so it is unto this day.