Voltage Regulators or Diodes to drop voltage?

Hi again,

Well, my linear power supply is working well. Too well in fact..
after the bridge recifier and capacitor, it's pumping out 38 volts.
This would be fine, only that the maximum voltage limit on my driver
board is 35V. Aaah!

Anyway, I need to drop off about 4V or so, just to be safe. Any
advice? I know I could just open the transformer and start taking
windings of the secondary, but (A) it's tedious as hell, (B) it's
probably defeats the isolation (my duct-taped result would certainly
not be as isolated as the original) and (C) ... it's just plain not a
good idea.

So I was wondering about other avenues? I'd heard someone talking
about using Diodes to drop the voltage on the line? What diodes do
you use for this and how many? (I can no longer find the message).. I
have some diodes around, but they're all meek li'l 1AMP ones, they'd
certainly become a small short-lived heating element on the 7AMP
power supply.

Also, what about voltage regulators? I know they don't make anything
above the 7805 and 7812 (no 7824).. but I know there are variable
ones available where you can set the output voltage with a resistor.
Again, looking on the web I've only been able to find some meek li'l
1.5ampers - which'll no doubt be carbon-toasties(tm) by the time my
steppers have vamped it. A voltage regulator would seem good - since
it might just save the driver board in the event of the AC power
supply jumping up a few volts in a surge etc.

Any advice welcome!
Thanks. :)