[snooper]

I see most DIY power supplies use toroidal/round (did I spell that correctly?) transformers; is there any advantage over using normal "square" transformers?

(my apologies if I posted in the wrong section)

[Al_The_Man]

Advantages are, a bit more efficient, more compact for size, but the big one for the DIY'er is that they generally are easier to modify, (add/remove turns etc).
Otherwise, you won't notice alot of difference.
They became popular with Audio amp. builders due to the minimum radiated energy reducing hum pick up etc.
Al.

[snooper]

They became popular with Audio amp. builders due to the minimum radiated energy reducing hum pick up etc.
Al.

Does this mean they produce less EMI?

[Al_The_Man]

This is why they are more efficient, there is less radiated magnetic energy, the figures I have seen are up to 8:1 less than for square laminate types.
Al.

[snooper]

Thanks Al, seems like I'll start hunting for a transformer now! Proves again that "round" is better than "square"...