9V DC wiring

[oldsoul]

Ok really basic question. I'll be using a VooDoo iso5 to power my Kingslayer.  When wiring up the D.C. Jack since the center pin is -9V should that be wired with a red or black wire? Also does that connect to them+ or - hole on the pcb of the Kingslayer. Sorry for the really basic question I'm just having a mental brain fritz and can't wrap my head around this.

[midwayfair]

DC "swings" one way: a voltage positive compared to one pin and negative compared to the other pin. That is, you could use the sleeve as ground and the center pin as -9V or you can use the center pin as ground and the sleeve as +9V. You cannot use the center pin as -9V and the sleeve as +9V at the same time. (The DC jack icon on the PCB being labelled + and - can be a little confusing, because that - is actually ground on this PCB.)

The standard wiring diagram, which you can download on the projects page, has wiring for effects that run on positive voltage. The Kingslayer uses that standard wiring (as do almost all projects on Madbean ... maybe even ALL the current projects). All the voltage conversion is done using the charge pump IC.

Just to be absolutely clear, you should only be using +9V DC to power this effect. Do not use -9V.

[m-Kresol]

to follow up on Jon's comment: How did you establish that it is -9V on the centre lug? If you measure the voltage with a multimeter/voltmeter you need to hook up the black (GND) probe to the centre pin and the red (positive) probe to the sleeve/outer pin. If you get a reading of +9V you have a centre negative cable/plug, if you get -9V, its a centre positive plug/cable. It's basically just a problem of the reference point as Jon said.

[oldsoul]

Thanks guys. I measured as you suggested. Black lead on my multimeter to center pin Red to sleeve and I got a +9.37V. When I'm wiring it up to the board my red wire should attach to the sleeve and go to the + hole on the PCB and Back to the center pin and to ground?

[m-Kresol]

exactly.
The red and black wire is of course more of a convention than a must-do.

another thing: the kingslayer has a built in charge pump, which doubles the voltage to 18V. However, the charge pump itself must not be supplied with voltages above 12V-15V or so (depending on the type, refer to the datasheet), so make sure to stick to 9V, so the charge pump will be safe.