Hello, I have a strange problem with the LM337 regulator. I have built a classic LM317/337 power supply - and it works, giving proper voltage, etc. however when I start it under load (approx. 300mA per regulator) using a switch, the LM337 goes into some sort of protection (audible buzz), but when I start the circuit under load using on/off switch on my laboratory power supply (I think the input voltage is rising then slower) the LM337 works as normal. I heard that when the LM317 is starting as first, then such effect may occur (but I don't know anything about this). What would be your first suggestion in solving this problem?