power supply Hum problem

[dromilious]

Hello all.I have a problem with my power supply.It is a one spot supply.When i connect it to the pedal(booster) it makes a hum.When i plug a battery i have not any noise.How can i solve this prolblem?
thanks

[ckim715]

Ground loops. It's a common problem with daisy chained power supplies. The solution is to buy a regulated and filtered power supply such as the Voodoo Labs Pedal Power 2 Plus.

[nzCdog]

How many pedals are you trying to power at once? 
What booster pedal is it?  Are you connecting your amp and pedals to the same power wall socket?

[dromilious]

I used this adaptor http://www.visualsound.net/index.php/products/pedal_power_supplies/1_spot_power_supply.It is a Jack Oman's Mosfet based booster.I used it with a MXR chorus powered both with the 1 pot adaptor.I tried also with an other adaptor alone.

[nzCdog]

Hums are often caused by bad cables, so make sure all the cables you're using are good... don't assume they work fine, you'll need to test them by experimenting.

You should double check your wiring in the pedal, making sure you have all electro caps in particular...  you may find an improvement by adding a 100uF electrolytic capacitor filter, going from the 9V lug on the DC jack (+ lead on capacitor) to the ground lug on the DC jack (- lead on the capacitor).

You may be getting interference from TVs, computers, light dimmers or other electrical appliances at your home.  You can experiement to see if turning these things off improves your hum problem.

Assuming your booster is correctly wired and its not interference from something else, then it may be a ground loop problem.  The easiest way to test this is to run the effects on different power supplies, if this fixes the hum then you may need to get a multiple isolated output supply like ckim715 mentioned.

Good luck

[dromilious]

thank you very much for your advise.I will check them!