I need 90 VDC to test an old battery radio.

Can I hook up a couple of triple power supplies (each is 5V/20V/20V and can be added together for 45V, then I need two of them) to get 90 VDC? Or is there some ground problem/issue I am not aware of?

I'll post over in videokarma too, since this is for an old radio.

It depends on the power supply. If the outputs are floating (negative terminals are not tied together internally), it should be fine. I use an HP 6228B dual 0-50V connected in series to get 90 volts.

I can do the supply itself.

What about using two seperate supplies??

Jason

Again it depends on the supply. If the negative terminal is connected to either the neutral or ground on the AC plug, it won't work.

perhaps you could just build a 90 volt supply from scratch ? Here's a very simple transformerless circuit http://www.antiqueradio.org/bsupply.htm

I ran across that page a while back, forgot about it. I might do that if I don't do somehting else. The radio I have only needs 1.5V and 90V. I guess I could always go the 10 9V route.

I want to see if this works before I construct a permanent supply for it.

I'll look on E-bay for a bigger supply, always a good excuse........

Jason

You could go to the dollar store and buy ten cheap 9-volt transistor batteries and snap them together + to - and get 90 volts for your test. You might be surprised how long they would last, too. If you need intermediate voltages just capture a wire between snapped terminals at the appropriate point between batteries. Ditto for your 1.5 volt supply: put a couple of D cells in parallel for more amp-hours.

I was under the impression that the 9V's wouldn't last that long. Looks like from some basic informaiton, Alkalines would last at least 10 hours.

If I had enough AA battery holders (I used to have tons for old CB's, 8 each for 12 Volt, probably tossed them), I could get close with AA rechargeables I bet. Well at least 1/2 there.

Jason

http://home.comcast.net/~morrised2006/radios/752instructions.pdf

Simple!

Cheers,