Wall Warts & Hum

[Fenderson]

What are some ways to deal with wall warts in a Guitar rack?

 

I've seen posted that distance from audio lines. & equipment is possibly the best solution - I've seen 6" min recommended for studio gear.

 

It's not easy when I need 9vdc 9vac 12vac 18vdc & 120v to run all the gear and would like to keep things in a small box.

 

I'm aware of power pads such as voodoo labs pedal power. But for monitary reasons I would like to stick with the power supplies that came with the units.

 

 

Any thoughts? Any tricks?

[HairyScaryMark]

Maybe if you list all the devices you need to power, it might be easier to suggest a solution as some devices that claim to require AC power, don't actually need it and some devices that run off 2 x 9V batteries, don't use all of 18V etc.

 

There are also some cheaper multi power supplies available, although usually involve a degree of compromise

[WRGKMC]

Most rack units use a specific wallwart, same goes for most pedals. Something like a Boss pedal will hum like a sob unless you use a zero hum adaptor. Substitute wall warts for rack equipment can also cause all kinds of hum, An alesis for example runs on 9vac. If the current draw is wrong or the cable is unshielded it will hum badly.

 

If all of that is Kosher, then the best thing to do is disconnect one unit at a time and find the culprit causeing the hum. In some cases, like mine I have an old Yamaha rack unit that will hum. Its direct AC and when connected with other units the darn thing just generates hum. I put a ground lift adaptor and bingo its gone. I'm not worried about a shock hazzard because all the cases share a common ground. I also get an issue connecting my amp to my recording interface. they are on separate AC lines so I use an isobar, Isolation transformer to prevent ground loops and remove hum.

 

Identifying which unit is causing the problem is the first step though. Till you do that no cure is possible.

[Fenderson]

Maybe I asked the question wrong - each transformer adds just a little more hum - to the point that it becomes to much hum.

 

I guess I'm asking the best place to locate the tranformers would be?

Is it just a question of getting a much bigger box?

[WRGKMC]

I have all kinds of warts in close proxcimity to my rack units with zero hum. If you are having hum issues and have then on a strip mounted close in there. Loossen the strip and try moving it around for minimal hum. If you do have tight quarters and the warts are causing the hum through EMF emission, a deeper box might help. Also High quality cords. The EMF is probibly leaking in because the cords and jumpers are have crappy shielding. getting jumpers and cords that have 90% shielding vs 70% makes a huge difference. You could also try putting the power strip in a metal box or maybe put a grounded metal plate between the rack units and AC wall warts. You can also try a metal AC strip vs a plastic, and make sure it has surge protection which seems to help a littel too.

[Fenderson]

Well it was the gcx (no pedals connected). I'll put it in a different case problem solved.

 

Still getting a very slight noise from the 50/50 power amp fan at the speakers(same sound as at the fan itself). Guess there's nothing I can do about that ?