two rectifiers one transformer?

[homer09]

Hi,

I was just wondering if anyone has built a gainclone using a single transformer which branches out to two rectifier boards. I was looking at BrianGT's gallery of finished gainclones, but no one seems to be doing this.

Is there any advantage of using two rectifiers, or is there really only a difference when you have two transformers? Is this more or less of an issue with a snubberred power supply?

[pinkmouse]

To use two rectifier boards with one traffo, you need to have split secondaries, ( four wires coming out, for instance: 15-0-0-15), not just a centre tap, (three wires: 15-0-15)

Oh, and two rectifiers reduce noise, and enable better rectifiers, (usually lower current handling), to be used if required.

[HDTVman]

The only advantage to using 2 rectifiers (bridge type I assume) is to provide seperate filtering for each channel of a 2 channel amp. This can result in better crosstalk performance and somewhat better PS regulation than a single rectifier/filter type of power supply. This results from each channel having it's own filter caps.

The only down side is that the extra caps and rectifiers will take up room in the chassis.

I'd say go for it.

BZ

By the way you can do this. just parallel the bridges with the output going to each set of caps.

[homer09]

Originally posted by HDTVman

The only down side is that the extra caps and rectifiers will take up room in the chassis.

I see another disadvantage...cost

Thanks for the quick replies guys.

Yes pinkmouse, i was planning on using a dual secondary transformer, thanks for the confirmation.

Im going to be using the BrianGT boards (more specifically his new snubber board), so i will just split each of the transformer's 4 leads into 2 leads for a total of 8. Then feed 4 leads to each rectifier.

Does that make sense HDTVman?

[tschrama]

Hi,

I think I did exactly what you describe: one xformer, dual secondary, 2 diode bridges (16 diodes) .. if you do it neat (1 real star ground) it can work just fine.. weird thing was that I didn't like it that much... I thoughd that a single bridge sounded better... so I converted back to 1 bridge, but maybe I folled myself..

[homer09]

Originally posted by tschrama
Hi,

I think I did exactly what you describe: one xformer, dual secondary, 2 diode bridges (16 diodes) .. if you do it neat (1 real star ground) it can work just fine.. weird thing was that I didn't like it that much... I thoughd that a single bridge sounded better... so I converted back to 1 bridge, but maybe I folled myself..

Thats interesting. Ive also heard people say the same thing about dual transformers. They sound is a better smoother, softer with a single supply.

What differences did you notice? I was considering this for a snubber supply, and since this is a high capacitance supply, i think their will be a much more noticeable difference. Any thoughts?

[HDTVman]

[
Im going to be using the BrianGT boards (more specifically his new snubber board), so i will just split each of the transformer's 4 leads into 2 leads for a total of 8. Then feed 4 leads to each rectifier.

Does that make sense HDTVman?

Ya, that should be OK. I scratch build so I can make it any way I want and was thinking that way when I answered before.

Good luck

BZ

[AudioFreak]

Using dual secondaries with 2 bridges also puts less stress on the transformer.

[gmarsh]

Suppse you configure a transformer as center-tapped and rectify it with a single bridge rectifier to two rails, and the voltage on the two sides of the transformer winding isn't matched.

The "higher voltage" winding will handle more current. Depending on power supply load, input capacitor size and how bad the voltage mismatch is, it's entirely possible that the lower voltage winding won't ever conduct any current... Even with a small mismatch, your "full wave" input rectifier can resemble a voltage doubler.

Two bridge rectifiers prevent this from ever happening, since each rail gets its own winding.