Reducing rectified power output

[JRKO]

I have a nice R-Core 30VA 24V transformer that I want to use that should give 24x1.414=34V. The problem is I need between 25-30V for the preamplifier I'm planning on powering.

I usually use SMPS so don't have much working knowledge of how linear PS work. How can I reduce the power safely?

 

[rsavas]

You want to reduce or regulate the voltage not the power. It could be as simple as using a three terminal regulator such as a lm317