[gives]

Originally Posted by Southsidemusic

Hi Friends

I am going insane with this issue we are having now.

Background info and explanation:

Bought a crapload of new analog gear for the big room lately and now we have soo much analog toys we tend to turn off a few of the racks as the power needed to run all that is enough for a small village.

So everything has Neutrik connections and Mogami cables attached into 3 balanced patchbays of high quality.

The issue:

When we powered off the racks and only have say one rack filled with gear ON but the other racks which have all the gear turned OFF but still have some units in those racks patched into the Patchbays (with the units power OFF) we get a damn HUM low irritating as hell.

We tried all the tricks like swapping power outlets, checking cables and all that and every piece of gear in our studio goes into a seperate socket in the power conditioners and not one analog synth or outboard share sockets in the power units.

The weird thing:

When we power ON the units that are patched in and cause the hum noise the hum and noise disappears.

So in conclusion:

If we turn ON ALL the outboards and the same patch settings kept no noise at all but as soon as we power off the units still patched in the bayw some make a low noise hum like 1176’s, Neve 1073 pre’s, WA Buscomp, Bluestripe Rev A and Rev F
But not say Monster-2, WesAudio NG_Nuscomp, LA2A’s, Manley Comps and 500 series units etc etc etc ...

The culprits patched in but turned OFF like some pres and comps make the humming noise and as soon as we either pull out a patch cable or turn ON these units the humming is gone!

We never noticed before as all the studio runs off the same outlets so everything has been ON all the time which made the hum not there. But now with soo much gear we started turning off some of the units and racks and kept some patched in to the balanced patchbays and thats when we noticed that some units makes this humming sound until we either turn on the units or pull out the patch cable connection.

Does anyone here know why this only affect some outboard units and why the humming appear only when turned OFF and patched in and why other units doesn’t do this even though they are also patched in and turned OFF and why it disappeared when we turn these units ON again?

Thanks a million for any help as we googled and asked ans looked into verything we know like swapping cables in the patchbays and on the non humming units to the humming ones and vice versa but still only the same 8-10 units make this humming noise only when OFF patched in and stop of we unpatch or turn the. On.

All the best and let me know if more info is needed as I am going crazy for real and my stomach pain is maxed now.
Some units

If you are using any power strips that have surge/noise prior going into your power conditioning, that can totally cause problems. Also I have Equitech Balanced Power systems here for years and it's so quiet. Just another thing, I had a problem years ago when the rack itself was not grounding thing in it properly.
You probably covered this, but just thought I'd throw in on this-:)
Check out Equitech.. They are great and the people are still very helpful. The founder passed away unexpectedly a few years back, but the family and team are still going strong!
You are probably fine with your setup, but someone there might be able to help you out!
https://equitech.com