Hummmmmm How come ?

[HOTTUBES]

So , i attempted to build a poor mans 9 volt power supply box  by putting a small 9 volt dc wall wart
inside an enclosure , and then daisy chaining 4 , std 2.1 mm DC plugs off the wall wart , but now it's
got this horrible hummmmmm to it . It was dead quiet before i messed with it ..... How can you kill
this 60 cycle Hum ?   it's an awful big paper weight at this point .....




Any tips or help would be much appreciated  !!

Thank You !

[merlinb]

The transformer isn't bolted down firm enough, or something's wired up wrong...

[Jdansti]

Also make sure that you don't have any AC wiring located too close to DC power wiring. If you have any effects in the same box, keep the AC away from all of that wiring too.

[HOTTUBES]

Also make sure that you don't have any AC wiring located too close to DC power wiring. If you have any effects in the same box, keep the AC away from all of that wiring too.

This what i was wondering too . cause it's a pretty close fit in there ....
I guess i could remove it and try it again and see if it make a difference .

[Jdansti]

Is this a power supply that you've used in the past without any problems?  If so, it might just be how you've got the wires arranged.

[petemoore]

  When using 1 output into 1 effect [to eliminate 1 bad effect as possible problem, make sure it works right with a different power supply, or try a second effect as another single test subject]...does it hum ?
  Also if they're true bypass it's easy to take the circuits out of the signal path...and test each effect individually.
  Could be a lost ground / bad patch cable for that matter, 4 effects..the variables add up.

[HOTTUBES]

Another question i have ....

Why does my 9 volt power supply show 13.25 volts with a DVOM ?

[Jdansti]

Sounds like it's an unregulated power supply. If it doesn't say "regulated" on it, it probably isn't. You might need to look up the part # and check the specs.

[petey twofinger]

it may run at the printed voltage when it is hooked up to the device it was designed to power . it may not , but with nothing on it , it is essentially " load free "

this is also telling in that i would want to be careful , personally i have put masking tape and tested then labeled the no load outputs on a lot of mine . the main offenders are those " coby " or similar brand multiple voltage units , at the "12 volts  " setting they are putting out 18 .

[KazooMan]

A great project would be a regulated power supply for your pedals.  There are plenty of tutorials available.  Check out R.G.'s geofex site for one.  Also check out Steve's Small Bear Electronics under the projects tab for two sizes of power supplies.  He provides a ton of information with photos to show how to assemble the power supplies. 

Stable, clean DC power for your pedals is the way to go.  The initial cost will be recovered easily by eliminating batteries.

[HOTTUBES]

This one is a Mode Electronics unit , i don't know if its regulated or not ....
I will have to check ...

I powered up my Klon Clone today with it , and it was Horrible & LOUD !!
I had the back off the pedal for other matter's , and i noticed that the protection diode was getting hot , so i unplugged it fast !
Luckily there was no damage done , it still runs and sounds fine with a standard 9 volt battery !

[HOTTUBES]

A great project would be a regulated power supply for your pedals.  There are plenty of tutorials available.  Check out R.G.'s geofex site for one.  Also check out Steve's Small Bear Electronics under the projects tab for two sizes of power supplies.  He provides a ton of information with photos to show how to assemble the power supplies. 

Stable, clean DC power for your pedals is the way to go.  The initial cost will be recovered easily by eliminating batteries.

I really like your idea !!
I will look into it asap ....
Thank you !