GGG Bipolar Power Supply Question

[johnadon]

I'm afraid of my power supplies with transformers connected to mains (   ) so I've been getting rid of all of them for commercially available dc adapters. Well, I just decided to take the transformer out of my previously functioning 15-volt GGG bipolar power supply to connect an 18-volt dc source directly from a store-bought dc adapter. I'm connecting the output of the dc adapter to the points where the secondaries of a real transformer would go. Guess what? It's not working. I have only a rudimentary understanding of power supplies (which should tell you why I'm afraid of them) so I'm not sure if this is something that will work.

I'm measuring +15 volts between positive and ground which is good, but I'm measuring only millivolts on the negative side. Have I more likely shorted something or is this something that just plain won't work with the bipolar power supply as configured to the GGG specs?

A link to the GGG bipolar project file: http://www.generalguitargadgets.com/pdf/ggg_bipolar_ps.pdf

P.S.: Sincere thanks to RG Keen for scaring the living bejesus out of me in one of his earlier posts about the ramifications of using home built, non-UL-approved power supplies. I've decided mostly not to deal with anything other than dc.

[johnadon]

Figured out by experimenting that whatever I was doing was flawed in some way. Apparently the bipolar supply requires an a/c input or something else I don't understand. Off to the market to find an ac/ac adapter with 24v output to keep my hands off  the transformers (except for octave up circuits of course). I do at least trust the rectification/regulation part of my power supply.

[Nasse]

I think you could use ready made unregulated AC wallwart with suitable output voltage/power rating.

[johnadon]

Thanks, Nasse. I think that is certainly my plan at this point. Anything to keep me away from the mains.