Hi Guys,
I am looking to upgrade the power supply in my gainclone to Carlos' snubberised version.
I can get a 250VA transformer with a single centre tapped 28-0-28 secondary for half the price of one with dual secondaries.
Anything wrong with using a 28 - 0 - 28 transformer like so?
Also, the idea is to do this on the cheap. Any reason not to use 10000uf filter caps I have lying around?
I am looking to upgrade the power supply in my gainclone to Carlos' snubberised version.
I can get a 250VA transformer with a single centre tapped 28-0-28 secondary for half the price of one with dual secondaries.
Anything wrong with using a 28 - 0 - 28 transformer like so?
Also, the idea is to do this on the cheap. Any reason not to use 10000uf filter caps I have lying around?
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No (yes, it is wrong), you will short-circuit the transformer windings through the diodes supposed to generate the potential close to the mid-point. You need floating windings.
Try to find a current path from the mid-point and you will see the problem.
You can no doubt use your 10000uF instead of the 4700uF.
Try to find a current path from the mid-point and you will see the problem.
You can no doubt use your 10000uF instead of the 4700uF.
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No, it'a a fundamentally flawed approach.
With a single, center tapped secondary, you have to use
the FWBCT circuit to get a bipolar power supply.
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You can't use a transformer with a center tapped secondary in that circuit, it needs to have two totally separate secondaries.
Mike
Yeah I was just working my way through that. Transformer wiring always does my head in a tiny bit. I think i have it right this time round.
Would it work to wire the rectifiers to the centre tap as though it was dual secondaries?
The ultimate question here is can a centre tapped transformer be wired as dual secondaries?
Would it work to wire the rectifiers to the centre tap as though it was dual secondaries?
The ultimate question here is can a centre tapped transformer be wired as dual secondaries?
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Thanks Rayma.
I was afraid of that.
It looks like I have to spend the extra money for a transformer with dual secondaries.
I was afraid of that.
It looks like I have to spend the extra money for a transformer with dual secondaries.
I purchased a board with two diode bridges per channel. The bridges are parallel. Cannot see why circuit in post one will not work.
Using two single output center tapped winding transformers for stereo.
Using two single output center tapped winding transformers for stereo.
Or, you use a symmetrical regulator design such that you have a regulator for the positive rail and a regulator for the negative rail. You can use LM317(positive)/LM337(negative) but they have to be buffered with an NPN and a PNP power transistor. Then, you can use your transformer with a center tap.
The need for individual windings arise from your intention to stack positive supplies.
Such less trivial rectification arrangements require us all to think at least twice before being sure it will work well. It is certainly not only you having overlooked a problem with such constructions.
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