9V supply hiss

[Dimitree]

hi everyone
when I plug the 9V DC power supply in a stompbox I've made I can hear a subtle hiss in the audio path..even in bypass (true bypass).
in your opinion what's the problem? is a power supply issue or a stompbox issue? I can't try it with other stomps unfortunately.

[anchovie]

Who made the power supply? If it's a cheap switch-mode thing then hiss is usually to be expected. Try the pedal with a battery to confirm this (if you haven't fitted a battery snap, just clip on some test leads at the appropriate places).

You've probably done this, but make sure there's no hiss when you plug straight into the amp!

[Dimitree]

thanks for the help
I tried to put a 9V battery but unfortunately the stomp doesn't want to power up with it, I think it requires too much current and the battery can't give it (it's not fresh). tomorrow I will get a new one.
The power supply is a Godlike one, made for effects pedals (a cheap one, yes, but still for pedals, so regulated at 9V)

[davent]

Might try a 100Ω resistor in series with the power supply input followed by a 100uF cap to ground. Had a nice quiet, when powered by battery, pedal that would get hissy powered with a very good quality power supply, after adding those two parts the hiss issue dissappeared.

dave

[rockhorst]

I've had terrible results with the Godlyke supply, while others seem to have no problems with it.  I find it difficult to believe that a battery can't power your effect. What's the circuit? Most stompbox circuits draw very little current, except (mostly) digital ones. So maybe something else is wrong too? Need more info.

[merlinb]

I've had terrible results with the Godlyke supply,

The curse of switched-mode power supplies!