Using an external dual power supply

[heady]

I am just wondering, given the difficulty in obtaining 22-0-22 300VA toroids here. Is it possible to rig up a dual power supply, regulated to 30-0-30 to supply the board. Connect the ground to the AC ground, the + and - supply to the output positions of the GBU.

Will this achieve the purpose of powering the board adequately?

Thanks.

[thomaseliot]

Your external supply is an SMPS?

[heady]

Hi, can a SMPS be used with amp5? I am not very tech savvy. I was thinking of those power supply kits from people like Pers (http://home.swipnet.se/~w-50719/hifi/rfb02/index.html) to be used with larger voltage toroids and regulated down to suit the amp5. I am just curious if this can be done.

Thanks

[thomaseliot]

Heady, I don't understand. Per-Anders has not SMPS kits; the kit of your link is simply a rectifier, a fast high current version of AMP5 GBU.

For AMP5 you simply add a transformer: the PS is on board. Try this link, it is much cheaper than external PS.

http://www.distrelec.com/ishopWebFront/catalog/product.do/para/language/is/en/and/shop/is/YY/and/id/is/01/and/node/is/aeadaaadaaae/and/series/is/1.html

I would go for the 230VA 2X22V

Or you can buy everywhere 2 transformers with 2x12V secondaries. Put the secondaries in series to get 24V, then make a center tap connecting first trafo end with second trafo start. With this you get +36VDC (rectified).

[heady]

Hi, you are right, I put in the wrong link, it's a rectifier in my link. Pers has power supply pcb for sale on his site.

Your suggestion of twin transformers is interesting. Let say the transformer has two outputs for each secondary, a 0V and a 12V. So for both transformer, I connect the 22V of the first secondary to the 0V of the other secondary. So, now I get two transformers with 0-24V.

To create 24-0-24, I need to join the 0V of each transformer together? Am I correct?

Thanks

[thomaseliot]

Hi Heady,

correct. The right way to say the thing is this. Each trasformer secondary has a START wire and an END wire. You connect the END of the first secondary to the START of the second secondary: this way the two windings become one winding, so only one secondary.

When you have the two transformers with only one secondary each, you connect the END of the first trafo with the START of the second. This point is the CENTER TAP. The START will be +24V referenced to center tap, while END will be -24V referenced to center tap.

[heady]

You couldn't have made it any simpler. Thanks, it's very clear to me now.