Something weird happening when connecting my BSIAB II to the wallwart

[Subzero]

I've just finished a BSIAB II.

As long as it's getting power from a battery, it's dead quiet and the sound is amazing.
When I connect it to a wallwart (9V 1000 mah, this is what I use for all my pedals ...) it becomes louder and starts to hum (very noticable), it works just as with the battery but a bit louder, with a  change of tone and a lot of hum .
Any idea what could be causing this ?
How should I adjust the trim? what would be the best setting ?

Thnx
Itsik

[caress]

is it a regulated/filtered supply?  if not, that might be your problem...many circuits, especially high gain ones, tend to get some hum and bad noise going on with unregulated supplies.

[Subzero]

Yep, it is reulated.
Is it possible that the supply is putting out more the 9v/the battery less the 9V ?, Could this be the cause?

[aloupos]

Same thing happens to me with Dr. Boogie and some ROG pedals (Thor I think).  Loud hum with 1 power supply I have (says regulated).  They work fine with my voodoo labs pedal power though.  Hmm....

[dschwartz]

if the supply is regulated, i´m almost positive that you have a ground loop..
i see a lot of those cases when the ground for the supply is taken from the wall...

[Paul Perry (Frostwave)]

If the offending power supply is "surprisingly light", it's probably switchmode.
Regulated or not, one of my customers reported trouble (hum & strange but unpleasant sounds) with my Sonic Alienator - which disappeared when they used a linear supply (soon to be illegal in many places.)
Start stocking up on linear power supplies now!
(I might add, my Alienator has internal regulators.. still a problem with the switcher.)

[Subzero]

thx for all the answers guys but it's not the power supply. I've checked with 2 other power supplies as well as other pedals with this power supply.
The power supply is not faulty.
I've wired the pedal exactly like I wired other builds, it works fine, the only differance is that when you connect it to a power supply, it becomes  A LOT lauder and a buzz is added.
Any other ideas on what it could be ?

thnx
Itsik