Is this how Neumann KH80 speakers die?

[m_g_s_g]

I own(ed) two KH80 speakers, bought in 2020 (in eBay), that I used daily, connected to my desktop computer (as I shared in this post).

A couple months ago, the right speaker failed: first no sound came while playing music, then some low volume crackles were heard and finally a violent spark was heard - and seen, like a bright fire inside the speakers coming through its openings, that slowly extinguished itself. Finally, the magic smoke came.

As shocked as I was, I didn't start any action / contact support, because (1) I bought them second hand and warranty was expired, (2) I had moved to a different country since, and (3) that specific speaker once fell from my desk and had a small crack in the back cover - this was two years ago, and it continued working fine after that. So I thought this failure could be a delayed consequence of the fall.

Now, three days ago, exactly the same happened to the left speaker (I still used in mono). This time I recognised the crackles and was prepared to quickly record a video (shared below) after disconnecting it from the mains to prevent something worse after "the spark".

This speaker never fell. None of them was abused at high volumes since I bought them. I always switched them off while not in use, since the auto standby feature never worked well (as many others have reported).

The weird thing is that both speakers died within months, after years of use. Is this planned obsolescence? Are Neumann speakers consumables? Should they put a "Best before" sticker on them, like yoghourt? Should I sell them for parts / try to replace the failed parts?

Sorry for being sarcastic, but I’m not happy at all. Anyway, is this is how KH80s die?

 

[Penelinfi]

(2) I had moved to a different country since

No significant change in voltage I'm guessing? Or is the PSU multivoltage?

Would be interesting to see what failed and if it can be fixed.

 

[tifune]

Sorry for being sarcastic, but I’m not happy at all. Anyway, is this is how KH80s die?

Yes, it is

 

[respice finem]

I own(ed) two KH80 speakers, bought in 2020 (in eBay), that I used daily, connected to my desktop computer (as I shared in this post).

A couple months ago, the right speaker failed: first no sound came while playing music, then some low volume crackles were heard and finally a violent spark was heard - and seen, like a bright fire inside the speakers coming through its openings, that slowly extinguished itself. Finally, the magic smoke came.

As shocked as I was, I didn't start any action / contact support, because (1) I bought them second hand and warranty was expired, (2) I had moved to a different country since, and (3) that specific speaker once fell from my desk and had a small crack in the back cover - this was two years ago, and it continued working fine after that. So I thought this failure could be a delayed consequence of the fall.

Now, three days ago, exactly the same happened to the left speaker (I still used in mono). This time I recognised the crackles and was prepared to quickly record a video (shared below) after disconnecting it from the mains to prevent something worse after "the spark".

This speaker never fell. None of them was abused at high volumes since I bought them. I always switched them off while not in use, since the auto standby feature never worked well (as many others have reported).

The weird thing is that both speakers died within months, after years of use. Is this planned obsolescence? Are Neumann speakers consumables? Should they put a "Best before" sticker on them, like yoghourt? Should I sell them for parts / try to replace the failed parts?

Sorry for being sarcastic, but I’m not happy at all. Anyway, is this is how KH80s die?

View attachment 503985

My condolences. Such reports get me slightly worried, I got the "bigger brothers" (KH 310A), bought new in 2021, no problems so far.
Can you estimate the "power-on hours" of your speakers, and did you switch them off when unused, or were they running 24/7?

Lesson I learned from it: Disconnect ASAP when they aren't working properly, to prevent more damage.

 

[Sokel]

Lesson I learned from it: Disconnect ASAP when they aren't working properly, to prevent more damage.

...and pray they went cheap on PSU's capacitance .

 

[Sokel]

And another, stay AWAY AND CLEAR from the smoke when it happens, open windows, etc,, it can be very damaging for health.
(that stands for everything of course, not specifically for Neumanns)

 

[RobL]

Did you open it up to see what failed?

 

[sergeauckland]

Without seeing the insides, I'm guessing that the issue may well be the capacitor across the mains switch, or somewhere on the mains filtering. When these fail, and they do fail regularly, they emit a lot of foul smoke. Replacement is pennies, if you do it yourself. You may be lucky it's just one of those.

As to why they fail, they're there to protect from mains spikes, but can only take so much. If you've moved to Europe from the US, our higher mains voltage may have just stressed them a bit more.

As I said above, this is based on not having seen inside the loudspeakers, but I've replaced a few of these myself in equipment, and the symptoms were similar.

S.

 

[m_g_s_g]

[...]and did you switch them off when unused, or were they running 24/7?

I always switched them off while unused.

Lesson I learned from it: Disconnect ASAP when they aren't working properly, to prevent more damage.

I agree; I now regret not having switched the last one off faster after hearing the familiar "crackles". There was time enough time for that.

No significant change in voltage I'm guessing? Or is the PSU multivoltage?

The PSU is (was) multivoltage 100-240V and 50/60Hz.

Did you open it up to see what failed?

Not yet. I might do it.

You may be lucky it's just one of those.

Fingers crossed .

If you've moved to Europe from the US, our higher mains voltage may have just stressed them a bit more.

It was actually the opposite: US/110V to Peru /220V, both 60Hz; cables should be ok given the lower current to traverse them. Voltage fluctuations are higher and occasional spikes more frequent, for sure. But other equipment seems to be surviving for now, after two years.

Thanks to all for the condolences and suggestions. I'll share pictures if/once I open it.

 

[m_g_s_g]

That's how it looks like (not good). I've contacted Neumann just in case.

 

[Ktacos]

Ooof, that's looks like a tough fix if it is fixable. Not smart or experienced enough to offer advice there.

Other than the obvious spot, is this chips outer part like, chipped or blown off?

 

[respice finem]

This rather didn't generate too much smoke... What do the PSU caps look like?

 

[RobL]

This thread brings this 5 year old quote back to mind…
Post in thread 'Neumann KH80DSP Teardown'
https://www.audiosciencereview.com/...ds/neumann-kh80dsp-teardown.24116/post-813325

 

[tineared]

This is why I have avoided pricey active speakers so far
Good passives last "forever"
Let us know what Neumann's response is
Genelecs keep looking better and better (figuratively speaking )

 

[respice finem]

This is why I have avoided pricey active speakers so far
Good passives last "forever"
Let us know what Neumann's response is
Genelecs keep looking better and better (figuratively speaking )

Yes, passives have many drawbacks, but they last. And, an integrated amp is safer to send for repair (or, cheaper to replace, mostly).
Neumann had responded to the other thread, tl,dr: "don't worry, be happy". I'm trying to... (see sig)

The main problem IMHO is the risk of sending the loudspeakers - will they come back "in one piece"?
If mine would fail, I would send them in, but sell them later...

Another issue: Cheaper loudspeakers (like my JBL) would be probably "totaled" by such failure, because their repair would cost more than re-buying (unless I could repair them myself).

 

[dfuller]

Neumann's build quality on their smaller speakers has been suspect for a long time. I recall plenty of threads about the original KH120A failing on Gearspace, and it was almost always the plate amp. Often the capacitors just gave up the ghost.

Oddly it seems to (anecdotally) not be a meaningful issue on the KH310 or KH420. Maybe the higher market price allows for a higher BOM cost for board components? I know the 310s I owned were noticeably higher end in terms of power supply electrolytic caps (Yageo main primary cap + all Japanese secondary vs CapXon and JWCO) than the KH80 that was torn down here... Maybe that has changed. I haven't taken the plate amps of my KH420s off so I can't speak on those...

Unfortunately Neumann also will not sell parts or give schematics for repair, which is intensely frustrating.

 

[respice finem]

The KH310 and 420 are more often sold to "institutional" customers. Too many failures would mean big trouble ahead.

 

[tineared]

Yes, passives have many drawbacks, but they last. And, an integrated amp is safer to send for repair (or, cheaper to replace, mostly).
Neumann had responded to the other thread, tl,dr: "don't worry, be happy". I'm trying to... (see sig)

The main problem IMHO is the risk of sending the loudspeakers - will they come back "in one piece"?
If mine would fail, I would send them in, but sell them later...

Another issue: Cheaper loudspeakers (like my JBL) would be probably "totaled" by such failure, because their repair would cost more than re-buying (unless I could repair them myself).

For the last 20 years I have been living on twelve NHT speakers and five Parasound amps without any failures, and it's not for lack of trying
I don't mind spending real money on products that make me happy and will last.
I value performance, longevity and aesthetics, in that order

 

[AnalogSteph]

That's how it looks like (not good). I've contacted Neumann just in case.

It's a bit hard to tell without some more of the bottom edge, but that's either the active PFC or the main switcher that follows it. The magic smoke has clearly escaped. I assume the big guy is going to be a MOSFET and rather shorted between either end and the gate, hence all the carnage. Unfortunately 8-legged PFC controllers aren't exactly rare, checking the pinout may narrow down the field of potential candidates.

This thread brings this 5 year old quote back to mind…
Post in thread 'Neumann KH80DSP Teardown'
https://www.audiosciencereview.com/...ds/neumann-kh80dsp-teardown.24116/post-813325

The big boy filter caps are certainly worth checking, they would be the most likely candidates for damaging things (but one would have to be super-dead). That's definitely not the only scenario though. I would also look out for reasons why the MOSFET could become overstressed, or quality issues with it, or shorted MLCCs.

Side note, the plastic washer under the screw next to the affected area looks like it may be slightly cracked. Proceed with caution and glue it if necessary. I would check whether there's some metal washers available that would be small and thin enough to go on top.

In the early days of APFC computer power supplies, we also found out the hard way that dodgy mains can be lethal... a crappy switch of the somewhat sparky variety killed two rather fancy modified CWT units. The second replacement unit stayed in the box for years and eventually replaced a dead one in a then rather retro PC. Meanwhile we moved on with better mains switches and more rugged supplies (FSP with traditional passive PFC back then, it would have been 2003/4ish).

 

[m_g_s_g]

Before opening again the right speaker I decided to open today the left one (the one that broke in similar fashion months before), to compare the pcb "front" side damages. They look extremely and suspiciously similar.

This time I checked the PCB "back" side as well, where the capacitors are located. To my surprise, it looked quite clean. So yes, the damages seemed to be confined around that MOSFET.