[PointyFox]

I noticed humming in one channel of my headphones. It goes away when I touch a metal part of my amp/DAC.

I unplug my headphones and they continue to hum when the cord is in close proximity to the amp/DAC. Touching the amp/DAC makes the hum go away.

Unless the headphone cable is unplugged with any part of it touching my plastic desk. Then it picks up much louder hum when I touch the amp/DAC, and it doesn't matter where on my desk the cable is.

 

[ADUHF]

Ground loop?

 

[PointyFox]

Through what? Me, then the air, then through my non-metal desk?

 

[ADUHF]

If it's not related to grounding, then maybe there's some static built-up somewhere in the headphones. Or possibly the amp.

I am not that knowledgeable about electrical junk. I mainly just replied because noone else did.

The last time something like this happened with some of of my gear, I was getting bad (static?) shocks from the headphones. And both the amp and the headphones were dead a few months later.

I assumed it was related either to a bad build-up of static electricity in my apartment. Or a lack of proper grounding in my equipment or apartment's wiring. Or possibly both. I'm still not sure though. The problem has not happened again since I moved out of that apartment, and bought some new (and hopefully somewhat better made) gear though.

I do hear noise coming from my new headphones though sometimes if I leave them attached to the amp with no source plugged in.

Have you had any bad electrical storms in your area recently?

 

[ADUHF]

You might also get a more informed response on something like this in one of the other general forums, from users who've had more firsthand experience with this type of thing.

 

[PointyFox]

If it's not related to grounding, then maybe there's some static built-up somewhere in the headphones. Or possibly the amp.

I am not that knowledgeable about electrical junk. I mainly just replied because noone else did.

The last time something like this happened with some of of my gear, I was getting bad (static?) shocks from the headphones. And both the amp and the headphones were dead a few months later.

I assumed it was related either to a bad build-up of static electricity in my apartment. Or a lack of proper grounding in my equipment or apartment's wiring. I'm still not sure though. The problem has not happened again since I moved out of that apartment, and bought some new (and hopefully somewhat better made) gear though.

I do hear noise coming from my new headphones though sometimes if I leave them attached to the amp with no source plugging in.

Have you had any bad electrical storms in your area recently.

No, though they are electrostatic headphones.

 

[ADUHF]

My advice would be to contact the manufacturer.

You might also want to discontinue using the headphones and amp in the meantime, in case there might be some risk of them getting damaged by whatever is going on.

 

[PointyFox]

All my other headphones are dead quiet, just the electrostatic ones are picking up noise.

 

[castleofargh]

What's the rated sensi?

 

[PointyFox]

What's the rated sensi?

98 dB SPL/1mW

 

[castleofargh]

Ultra high sensi was my only guess and I doubt it suddenly goes from 98 @ 1kHz to 130 @ 10kHz. Sorry, I have no idea.

 

[ADUHF]

I don't know much about e-stats. But I believe they require higher voltages than normal headphones, and usually come bundled with specialized amps. Is that not the case here?

I still think the manufacturer is your best bet. And you should probably discontinue using them till you figure out better what's goin on. If they require more voltage though, then maybe they're more sensitive to things like grounding issues. Static electricity in your hair or clothes. Or higher humidity (most people suggest not using them with wet hair, for example). And reversed polarity on the connectors. Perhaps they are also more sensitive to EM or RF interference from other electronic devices as well.

Those are a few things I've sort of been able to glean from looking at some other topics on this. But the honest answer is that I really don't know... which is why I suggest contacting the mfr.

Fwiw, there should be plenty of e-stat owners though in either the High-End Audio or Fullsize Headphone forums that might be able to offer some better insights on this.

 

[ADUHF]

A related topic on Drop. Seems some other Koss users have had similar issues, and it may be related to the energizer on the E90 amp.

https://drop.com/buy/koss-esp950/talk/1914116

 

[PointyFox]

I've tried a different E90 amp and same results.

 

[ADUHF]

Another related topic.

https://drop.com/buy/massdrop-x-koss-esp-95x-electrostatic-system/reviews/2434613

It seems this is not an uncommon problem with these headphones. And one of the suggestions in this link is to try a different power source. But I would really STRONGLY suggest contacting Koss first before doing something like that!

If you've already been down that path with the mfr, and not gotten the issue resolved, then you should try posting your question in the appropriate thread for your headphones to see how other users are dealing with it. Just my 2c fwiw.