Floating ground power supply

[Theodore Julie]

I have a transformer with a single secondary 0-63V winding, after rectification i have a 90vdc single rail power supply. what would be the correct way to create a +45v 0 -45v split rail supply floating ground?

[richie00boy]

Put two caps in series across the rails each with a balancing resistor. The centre point is your speaker ground. Do a search for the recent thread in Solid State section about QSC amps using that method.

[Ponz]

there have many methods to split signal power supply to dual power supply, but it depeneds th supply current you need.

if you needs only under 500mA, just put two capacitors in series between the positive and negtive side in the signal power rail.
and it creates the simplist dual +-45v power supply, but the center point is not really stable.
So add regulator like zener diode is the better way, also this way will
drop a bit voltage down.

[Theodore Julie]

thanks for the speedy reply guys, i just wanted to be sure since the MOSFET amplifier output stage is about 400W into 4ohm. it draws heavy current and will be way above 500ma, so would the capacitor configuration still work?

[BWRX]

Nope. You should sell your current transformer and look for one with two secondary windings or a center tapped secondary.

[richie00boy]

If you can find the thread I mentioned you can see that yes it will work for your power amp. In fact QSC used it for a while.

[Theodore Julie]

Thanks ( BWRX ), I thought that much

[Theodore Julie]

(richie00boy), i tried searching in the solid state forum and did not come up with that thread you were talking about..will keep trying though..

[BWRX]

This is the thread richie is talking about: QSC style single supply

Yes, the search feature sucks unless you know what words to search for...

You can do that but I would still recommend finding a transformer with dual secondaries or a center tapped secondary.