looking for a 20vac transformer resource

I have a power supply that outputs 36vdc (24vac transformers)and I
want to get down to 30vdc. A 20v transformer would get me 28vdc, if I
have the math right, which is close enough. Where can I get one (or
2) of these. I want to drive the 4 axis Xylotex driver board and some
250 oz in steppers on my Taig mill.

Or a 24-30vdc power supply would work too, if the price is right.

Thanks,
Monte