A lot of noise from Wurly AUX / Headphone, even when it's powered off entirely

[elihu252]

I'm trying to figure out why my aux / headphone jacks are so noisy.  It's like a grainy crackle and hum that is constantly coming from the AUX output and the headphone output.  It doesn't matter if the device is turned off or on OR if the volume is up or down.  The level of the noise is constant.   The noise is the same in both outputs but considerably louder from the headphone jack.  The speakers sound totally fine clear.

I've tried different cables (balanced / unbalanced) and different wall outlets in different rooms of the house.

Aside from that, the sound from both outputs is clean.  It's so close to being usable, but definitely not right now.

[cinnanon]

the amp out signal goes to the headphone jack first then to the speakers. It should be a hot signal like you described but shouldn't be noisy. Sounds like someone may have farted around inside there. Check the wiring first. If the speakers are clean the aux out should definitely be clean.

[Tim W]

It is likely a ground loop causing your problem.

The key giveaway is "even when powered off".

Grab a ground cheater block from the hardware store.  They are little gray blocks with a 3 prong outlet and a 2 prong plug.  The 3rd prong is replaced by a green metal tab on the plug end.  Just don't let that tab touch anything grounded or just cut it off.  Use the block on the AC plug of whatever you are connecting the piano to. (i.e. amp, etc.). 

I should note here that this should be done AT YOUR OWN RISK.  If you have an electrical grounding problem *inside* either your piano or your amp, etc. you run the risk of shock by floating the safety ground.  For example, you may have a failed 'death cap' in your amp which will make the chassis live if it is not grounded.  Or, as cinnamon said, someone was monkeying around inside something and things are hooked up the wrong way somewhere.  The safety of your earth grounds should be checked before assuming floating ground is a safe thing to do.  But- one must also note that for decades tons of electronics and appliances were produced (and are still in use today) that do not have a safety ground (3rd prong).

A BETTER, and more proper way to address this issue is to use a direct box with a ground lift.  Or an isolation transformer, like the Whirlwind ISO1.  This way the safety grounds of all of your gear will still be properly attached to earth ground.  One must be careful with ISO transformers however--- if they are placed near a power transformer, motor, etc. the magnetic field may induce a hum in the ISO transformer itself, causing the same exact type of problem (hum/buzz in audio).  Usually relocating the ISO or turning it in a different direction in relation to the component generating the magnetic field can alleviate this issue.

Good luck!  and most importantly... BE CAREFUL!

Tim

[elihu252]

I'll do some more research on fixing the ground loop problems starting with the information you've provided.  It 'seems' like something that should be simple but who knows.  It doesn't sound like the sound is distorted, it just sounds like there are two totally different sounds coming from the aux. 

Thanks for the replies.