[VSTOLL]

So, last year I bought a HD660s and a FiiO K3 when I was in the USA traveling. I was enjoying the heck out of it, and then, May of 2020, the left side of the headphone just went silent, without a reason and without giving any signals. I sent to warranty, but because I live in another country, the dealer had to make a bridge with Sennheiser USA, and they didn`t had the HD660S in stock, only in August.

So I was using my trusty WH1000XM3, and decided to buy an AKG K702, brand new, to try a different sound signature and the claimed soundstage that the K7XX line has. I was liking it for classical music, but 3 days later, guess what? Yeah, left side went silent. I got a refund from the store I bought it and returned to my trusty WH1000XM3.
I was really pissed, so I started investigating what it could be. I narrowed it down to the amplifier and stactic electricity. So I exchanged the FiiO K3 for a FiiO K5 PRO, and changed the carpet floor in my office for vynil flooring.

Sennheiser sent the replacement directly from the USA to me, and I had to pay taxes to get the headphone. I paid it with the intent to sell the headphones once they arrived, and I bought a second pair of HD660s straight from Sennheiser in my country in August. The other pair arrived from US in october and I sold it, and the new one I bought here was working like a charm. Until today.

It's no mystery anymore, but I was using it at night yesterday, put it down to go to bed, when I went to use it today, the right side was silent. Back to the Sony.

The first HD660s got the left side voice coil busted for some reason, and I believe the same happened with the new one. I tried different cables and sources and it never worked.

I have NO clue what is going on. I thought it could be bad electicity but my PC should give me signals, and all my other stuff too, the Sony have electronics inside, and I use it plugged into the K5 all the time, and I never heard a single hiss or noise coming out of it. If anyone have a clue on what may be happening here, I would love to know.

I guess I ran out of luck this year or I'm not supposed to enjoy a good open back headphone for some reason. So I'll try a refund with Sennheiser instead of getting a new pair. This is ridiculously frustrating. My cheap pair of headphones that I had before the Sennheiser still works just fine...

 

[ADUHF]

Sorry to hear about your difficulties VSTOLL.

 

[Lokiiami]

This can be explained by science. Most likely your office has very high harmonics.. it can cause lifts and photocopy machines to malfunction as well.
https://www.mtecorp.com/blog/2018/04/13/what-causes-harmonics/

 

[VSTOLL]

This can be explained by science. Most likely your office has very high harmonics.. it can cause lifts and photocopy machines to malfunction as well.
https://www.mtecorp.com/blog/2018/04/13/what-causes-harmonics/

So, harmonics are generated by those heavy duty equipments? I should have explained better but by office is inside me house hehehe It's just the computer and my TV on a repurposed bedroom.

But anyway, if this is what causing issue, shouldn't I hear something before the driver fails? Like some crackling or popping. The last HD660s that died was even unplugged from the amp, I always unplug before putting the headphones away.

By the way I was researching some time ago the correct order to turn off a system, I came to no conclusions, but I usually lower the volume to the minimum on the amp, unplug the headphones and then turn the amp off and right after that the computer. The first 660s that died on me I always left plugged, just turned off the amp. Dunno if this is causing something either, I know something must be happening but I can't really understand what and have no evidence

 

[ADUHF]

^ Some excellent questions which I don't know the answer to.

Those might be some good questions to pose to the headphone manufacturers, if you have that ability.

I have sometimes heard loud noises coming from my headphones when leaving them connected to a turned on amp, with the sound sources turned off. So that might be one thing to try to avoid.

Grounding might also be something to look at.

And maybe also the humidity in your office. Not enough might contribute to static buildup, which can be a problem in the northern hemisphere around this time of year, due to people turning up the heat in their homes. Too much could also potentially cause other issues.

It's a little odd that your Sonys so far seem to be uneffected by whatever is going on, and all the other headphones are not. Kudos to Sony I guess.

 

[ADUHF]

Interference from other electrical devices could also be something to look at. Including loudspeakers.

Issues with your sound source could also be something to consider. Especially if you're using some type of computer as your source.

 

[ADUHF]

A mismatch in impedance between the headphone and amp could also be something to consider.

Are you having to crank up the volume on the amp with some of these headphones to get decent sound levels?

Maybe your gear just doesn't play nice with the FiiO amps as well. And you should try something different, made by a reputable mfr. Maybe the headphone mfr could offer some ideas on that as well.

Aside from that, maybe a call to your local headphone exorcist or ghostbusters is in order.

 

[VSTOLL]

^ Some excellent questions which I don't know the answer to.

Those might be some good questions to pose to the headphone manufacturers, if you have that ability.

I have sometimes heard loud noises coming from my headphones when leaving them connected to a turned on amp, with the sound sources turned off. So that might be one thing to try to avoid.

Grounding might also be something to look at.

And maybe also the humidity in your office. Not enough might contribute to static buildup, which can be a problem in the northern hemisphere around this time of year, due to people turning up the heat in their homes. Too much could also potentially cause other issues.

It's a little odd that your Sonys so far seem to be uneffected by whatever is going on, and all the other headphones are not. Kudos to Sony I guess.

I do know that if I leave the headphone plugged, I hear a little pop when I turn off the amp, but it's not loud.

Yeah, I was really afraid of static, that's why I changed the flooring from carpet to vynil flooring, I also freaking hate carpet, it's really annoying to clean, and the possibility of my PC or other stuff dying from static made me change it. I also live in Brazil, so it's as hot and humid as it gets in this time of the year hehehe

Interference from other electrical devices could also be something to look at. Including loudspeakers.

Issues with your sound source could also be something to consider. Especially if you're using some type of computer as your source.

There's not much on my desk, I don't use loudspeakers either. All I have is 2 monitor, my PC that is behind the desk and that's it, my TV is further away and plugged into another wall outlet. Also, shouldn't I hear something before it just giving up and dying? I mean, I live in a building and there's a lot of wi-fi networks here, I usually leave my phone on my desk and I never heard any interference from them.

A mismatch in impedance between the headphone and amp could also be something to consider.

Are you having to crank up the volume on the amp with some of these headphones to get decent sound levels?

Maybe your gear just doesn't play nice with the FiiO amps as well. And you should try something different, made by a reputable mfr. Maybe the headphone mfr could offer some ideas on that as well.

Aside from that, maybe a call to your local headphone exorcist or ghostbusters is in order.

I really don't have to crank the volume, it usually sits on the lowest gain and the volume dial between 9 and 10 o'clock. 7 o'clock is the minimum and 5 the max. The HD660s is not really demanding, I can get pretty good volumes even with a phone.
I was thinking of changing the FiiO for a SMSL AD18 or a Topping DX3Pro, mainly because I can control it with a remote and I could run an optical cable from my TV to the amp, but I dunno if is really the amp, I always heard good things about the K5 Pro.

I'm in contact with Sennheiser and I managed to talk to the guy who fixes the stuff in warranty, and he said he only got 3 HD660s headphones there, 2 beign mine hahaha and the other one was from a guy that does music production and his equipment sent a jolt of electricity to the headphones, but even that didn't killed it, just damaged the drivers a little, that made it distort a little. He told me that what I'm experiencing shouldn't happen at all, and I think he'll help me find a solution or at least give me a clue to what may have happened.

By the way, thanks for the repplies, I hope that this will be the last time I have trouble with them

 

[ADUHF]

The problem may not be in the amp. I was just throwing that out as one possibility. I frankly don't really know much about any of the hardware you're using. But I have been deterred from getting FiiO products by others here who I assume would know more about them.

SMSL and Topping are also made and designed in China I believe, like FiiO. That doesn't necessarily mean they're bad. And I have heard some fairly complimentary things about Topping here by a few individuals. If the issue is related to the FiiO though, then I would probably think twice before investing my money in another Chinese product, that may not have to meet as rigorous standards as things made elsewhere.

Alot of geeks and gamers like the cheaper Chinese stuff, because they often have additional features they can't find on other potentially better-made hardware. You may sacrifice some reliability though, going that route.

If you're in contact with the folks at Sennheiser, you might try to hit them up for some suggestions. Or see what others using your headphones recommend here. Sennheiser will probably try to get you to purchase one of their ridiculously expensive amps.

It seems to me though that you're buying some pretty nice headphones, and then pairing them with (how can I put this diplomatically) less nice hardware. And expecting good results from that.

If I'm off base on any of the above. I'm sure someone else will dive in here, and point it out.

 

[ADUHF]

If you live in an older building with bad wiring, then perhaps some type of power conditioner might also be worth considering.

Again, just throwing a few ideas out here, since I don't really know what's goin on. But some electrical devices, including amps and what have you, can be be a little touchy when connected to a poor or less reliable source of electricity.

I assume you have storms in Brazil as well. So maybe the issue could also be related to lightning strikes or other power surges in your electrical grid. And maybe you need some better surge protection against that kind of thing.

You might also ask the folks at Sennheiser if high levels of humidity, sweat or moisture accumulating especially in the earcups of their headphones could effect their performance at all. Or maybe try to use a fan or towel to keep them somewhat drier, if you think that might help.

 

[VSTOLL]

The problem may not be in the amp. I was just throwing that out as one possibility. I frankly don't really know much about any of the hardware you're using. But I have been deterred from getting FiiO products by others here who I assume would know more about them.

SMSL and Topping are also made and designed in China I believe, like FiiO. That doesn't necessarily mean they're bad. And I have heard some fairly complimentary things about Topping here by a few individuals. If the issue is related to the FiiO though, then I would probably think twice before investing my money in another Chinese product, that may not have to meet as rigorous standards as things made elsewhere.

Alot of geeks and gamers like the cheaper Chinese stuff, because they often have additional features they can't find on other potentially better-made hardware. You may sacrifice some reliability though, going that route.

If you're in contact with the folks as Sennheiser, you might try to hit them up for some suggestions. Or see what others using your headphones recommend here. Sennheiser will probably try to get you to purchase one of their ridiculously expensive amps.

It seems to me though that you're buying some pretty nice headphones, and then pairing them with (how can I put this diplomatically) less nice hardware. And expecting good results from that.

If I'm off base on any of the above. I'm sure someone else will dive in here, and point it out.

It's really hard to get other amps here, that's why I went with FiiO. I've seen a lot of people pairing the K3 and K5 with the HD660s, as it's not a heaphone that is hard to drive and it's not picky with amps like the HD650. I was getting good results with it, it just doesn't make much sense for it to just die like that, without even distorting the sound a little. As far as I know, the drivers are not as sensible as people usually think they are. Also I can't afford to expend the same amount on the amp as I did on the headphone, especially since it's not really a guaranteed fix. I've seen a lot of people using a HD660s and HD58x directly into the PC or Macbooks, and they don't seem to have problems, and I dont think that a cheap motherboard or a macbook has better audio components than the fiio.

It's storm season here, but didn't had any last week. Power here in Brazil is pretty bad, and 99% of the houses aren't grounded. I use a pretty good surge protector, the amp also has it's own power brick that Fiio says cleans the power quite a lot, dunno about that.

Sennheiser will only return to me after holidays now, but I'll try to get as much information from them as possible. I'll try to call an electrician to take a look at the power in my apartment. But even if the power is that bad, I believe my PC and other electronics would crash randomly and I would hear weird stuff coming from the headphone.

There's still the chance that it's just the solder that came loose for some reason, I won't open the headphone because I'm not comfortable doing that and I'm not skilled with soldering irons, so I'll wait the diagnostic from Sennheiser, but they told me that the first one was beyond repair because the voice coil on the left driver was burnt.

Sennheiser does sell one headphone amp here, but it's ridiculously expensive, just like you said. To be more precise, it's R$15000 (US$2800), and that makes it more expensive that everything that I have in my room combined hahaha.

 

[ADUHF]

Well, I wish you good luck in figuring this out. And please let us know if you learn any more about what's going on.

Happy holidays btw!

❄❄❄​