another transformer question

Hi,

This is another transformer question. Seeing that the Gecko likes
high voltage, I am now in the process of upgrading the power supply,
changing the 24VAC transformer to a 36VAC transformer.

So, with a 36VAC secondary, a bridge-rectifier plus capacitor, I
should get about 48VDC, right?

Wrong! I got only 25VDC!

Only thing is, I am using the output from the bridge rectifier to
drive 2 (two) 12V 1.8A fans in series plus a 150ohm 5W resistor. I am
doing this so that the fans can act as a blled resistor.

Why can't I get 48VDC with this set-up?

Thanks

Peter