Power Question... 18v from dual 9v jacks?

[no one ever]

I've seen the drawing by M.F. at Fulltone for getting 18v out of 2 9v batteries, can the same voltage be had from dual 9v jacks hooked up similarly?

if so , can they be fed by a single daisy chain?   

[R.G.]

In general, no. Unless the dual 9V jacks are specified as completely independent, they are wired in parallel behind the jacks. Wiring them in series just shorts one of them out.

You can tell by using your ohmmeter on the power supply that provides the dual 9V jacks. Leave the jacks unpowered, and measure the resistance between both - contacts and both + contacts. If there is less than 1M between either the two -'s or +'s, you cannot stack them for 18V.

[gener]

i have 18v cables for my VL Pedal Power. my 15-18V effects work fine with them, so i would think that it's possible.

not sure about the second question.

[R.G.]

The voodoo labs power supply is one of the few - and maybe the only - power supplies available that can do this. The VL power supply is the reason I described the test for independence so carefully. The VL power supply is internally a one-transformer Spyder power supply as shown in my article at GEO. It's outputs are fully independent and will pass the ohmmeter test.

Ted Weber sells a suitable power transformer for making a Spyder-type independent-output power supply that will also pass the independence test.

There may be others but I don't know of them. And none that I know of will run two independent outputs from one 9V daisy chain.

I suppose my reply should have been "Yes it's possible, but only with a Spyder-type power supply, and here's why..."

[no one ever]

  Much appreciated, gener and R.G.

The recipient of the neovibe I will be building is planning on getting the PedalPowerII, so I guess I only have to put in one 2.1mm jack. I'll be running it on double-9v's for testing purposes, however.