regulated supply with one bridge

[velikan]

Hy.

I didn't think of it when i bought yesterday my toroid but here is the problem: how to put two lm338 voltage regulator on psu with one rectifier bridge???
My trafo don't have two separate windigns but star point. I am afraid that i will make closed loop with two rectifier bridge

[ebijma]

To my knowledge its not possible to use this Pedja lm338 circuit with only one bridge.
You should use an other kind of regulator circuit.
Or an other toroid.

[macboy]

ebijma is correct; in order to use two positive regulators (e.g. two LM338's) you need two completely isolated supplies, and that means either a dual-secondary transformer (not a centre-tapped one) or two transformers, and a bridge rectifier for each. If you have a centre-tapped transformer and/or only one bridge, then you need to use a negative regulator for the negative rail, since the supplies share the common ground point.

[velikan]

Yes, i thinked so.

Luckly, i managed to separate the star point.

Thank you

P.S.
What people says for Carlos Filipe capacitor inductance compensation. I am using some capacitance after regulator.

[Gcollier]

I'm not sure what you are powering off of this but you could resort to LM317/LM337 split regulated supply. This won't handle 5 amps like an LM338, but it will handle 1.5. This is likely enough for one channel of LM3875/LM3886 but you would be pushing it with 2 channels.