Harbinger one strong / noisy hum

[small fish]

Hi guys,
I just finished my Harbinger one (old Layout) and seem to have some issues, maybe you got some clues for me:

- EH wall-wart, 18V
- LM7815AC IC
- LDRs / bulb from Banzai, recommended parts for Univibe-build

The sound-volume of the fx is very low -  but I get a very loud hum. It seems like a hum from the wall wart or some grounding issues?!? 
Pushed the button (bypass) and the guitar signal is perfectly silent to the amp, no hum, no issues. Activating the fx and it´s humming like hell.

I can´t help, but I think it might be the wall-wart. It´s an Electro Harmonix, 18V, 500mA - so I think there´s no fault with the voltage. I got no other wallwart with 18v so it´s difficult to change, nor do I have  the charge-bump IC at hand, so I can´t change to 9V at the moment.

Does anybody have some experience with the EH wallwart?

Any help or ideas will be appreciated.
If you nee any more information, plz let me know.

Regards
Carsten

[RobA]

Check the polarity on the EHX power supply. Some of them have center positive outputs.

[small fish]

Hi, this one is center tap positive, but it´s wired that way.
I had to order another socket for the power connection, coz it´s slightly bigger than the normal pins / sockets.
any other suggestion?
I may order a Dunlop and send it back, when there´s no difference. we´ll see.

thx RobA

[RobA]

It should be fine as long as you've wired it to match. A loud hum always makes me suspicious of a ground issue somewhere. I'd start by checking all the ground continuity first.

[small fish]

ok. first problem solved:
the INT pot was broken with a short circuit inside (I suspect....). Changed to a new one and it sounds as it should.
Still to find:
the cause for that annoying hum. I ordered a Dunlop ww and hope, that´ll fix it.

resoldered all (!) connections to avoid cold solder anywhere.
We´ll see.

Thx so far
Carsten

[small fish]

The Dunlop wall-wart arrived today. Believe it or not: the pedal is dead silent now
It really has been an issue of the EHX power supply, I didn´t expect that.

thx
carsten

[RobA]

Congrats on getting it working! Now for the fun of playing with it.

I'm surprised the EHX power supply had that much hum even with all the filtering on the 18V filter board. That's pretty nuts really.