PSU is acting weird (+ and - 15V); fixed

[Bernardduur]

OK, I build this PSU with a transformer (+ 27V) and the bipolar PSU from GGG. I used a 7815 (S?) and a 7915 (Motorola).

My problem:

I've build a Kreuzer bass preamp and with no FET's on the board I get +15 and -15V. When I add the FET's my power suddenly drops to +4V and -26V..........

What can be wrong?

Edit: OK, I found it. I used trimpots on the emitters to adjust the FET's to the desired voltage, but this was messing with it. Now I adjusted it by adding a fixed resistor to it and now it works great!