Is this how Neumann KH80 speakers die?

[AnalogSteph]

The schematic is probably close to what's found on page 12 but will differ as it uses the LNK603PG as feedback circuit it seems.

I hadn't even noticed that one. This is the kind of IC that I could also imagine being responsible for a standby power supply.

Most likely scenario is the poor quality of the exploded caps setting this all in motion.

I still don't exactly see how though. If it was a dead primary-side filter cap, yeah, those have been known to kill SMPS controllers. There may be some other design defect, like the case of the exploding Gigabyte power supplies.

One thing is for certain, C220 is worth keeping an eye on and probably worth replacing by something higher-grade preemptively if wielding a soldering iron is second nature to you.

I was going through an early-'90s Pioneer tuner being stuck in muting on FM with the ESR meter the other day... loads of dead Elnas in the power supply section (poor thermal design + decades of standby) making it a miracle that the thing even powers up, but no carnage. In fact, I've had to replace several shorted electrolytics in tuners but things always failed gracefully. OK, another kind of device from another time...

I guess designs these days could use some more "what if part X fails" testing. Or "get a device in service few a few years and check caps for leakage + ESR" testing.

 

[Hasse]

To mgsg: No, I was thinking more about what looks like white discoloration and dull surfaces on the circuit board's solder joints.
For example those marked in red on attached photo.
If you as the owner know that the speakers have not been exposed to significant humidity, this is of cause not the case.

 

[RobL]

This morning I've received an answer from Neumann's customer service. They want to further investigate the issue, so I'll send them the speakers and they offer me a replacement, even if the warranty is clearly expired.

I was going to say that Neumann would probably want to do some post mortem analysis of these failures…good on them for offering to replace them!

 

[Digby]

In many cases, it's the "growth trap". With longevity, the market is saturated one day, and unless real innovation occurs, growth is not possible any more. I'm not saying Neumann does this, but it occurs in all trades, more or less. Conflict of interest: manufacturers want to sell more and more, customers want longevity.

Yes, of course, and Neumann are no different from any other manufacturer in this regard, but what with a dying planet (supposedly), why can't manufacturers be encouraged (either themselves or by governments, perhaps?) to have, depending on the cost of the original goods, a significant window in which repairs can be carried out locally.

This loudspeaker (both speakers?) now have to take a trip back to Neumann, possibly overseas, emitting carbon unnecessarily, when manufacturers of products above x price point could be required to release documents (if to only local "approved" dealers, then fine) so that speakers/amplifiers and other such electronics can be repaired locally.

I mean, look at all the amplifiers & loudspeakers from as early as the 1950s and before that are still running - it may not have been the manufacturers intentions for them to have such long service lives, but there is little reason why they shouldn't and given climate change is taken as a given, perhaps throwaway electronics, where possible, should be heavily discouraged and avoided?

I think there is something similar going on to this end in American legislature at the moment (the right to repair bill).

 

[respice finem]

Yes, of course, and Neumann are no different from any other manufacturer in this regard, but what with a dying planet (supposedly), why can't manufacturers be encouraged (either themselves or by governments, perhaps?) to have, depending on the cost of the original goods, a significant window in which repairs can be carried out locally.

This loudspeaker (both speakers?) now have to take a trip back to Neumann, possibly overseas, emitting carbon unnecessarily, when manufacturers of products above x price point could be required to release documents (if to only local "approved" dealers, then fine) so that speakers/amplifiers and other such electronics can be repaired locally.

I mean, look at all the amplifiers & loudspeakers from as early as the 1950s and before that are still running - it may not have been the manufacturers intentions for them to have such long service lives, but there is little reason why they shouldn't and given climate change is taken as a given, perhaps throwaway electronics, where possible, should be heavily discouraged and avoided?

I think there is something similar going on to this end in American legislature at the moment (the right to repair bill).

Apart from some "greenwashing", nobody will do it voluntarily, because they will lose against those who don't.
Mandatory legislation could do it (longer warranties, service manuals, etc.)
But, a good mitigation would already be to have the electronics of active speakers in an external module (like recent Genelecs), so in case of a failure only that module would have to be sent back.

 

[wwenze]

Could it be that you moved to a country where the AC is crappier

This is finally one actual situation where a power filter or power regenerator is useful

As mentioned, it's 220V / 60Hz here (weird combination). Other equipment (mostly bought in Europe, some in the US but with multivoltage PSU) seems to be surviving (LG OLED TV, many Sonos speakers and Amp, PC with huge dual Dell 4K displays, Brother Laser printer, QNAP NAS,...).

It's hard to say really. Some manufacturers test their product for use in the country they sell the products, I don't think there's any KH80 seller in Peru.

I'd expect big companies to have products that can take a way harder beating.

 

[Digby]

But, a good mitigation would already be to have the electronics of active speakers in an external module (like recent Genelecs), so in case of a failure only that module would have to be sent back.

This seems a sensible enough approach, but if it has to be sent back to another country, then it is only half a solution to unnecessary airmiles IMO.

 

[markstein]

To mgsg: No, I was thinking more about what looks like white discoloration and dull surfaces on the circuit board's solder joints.
For example those marked in red on attached photo.
If you as the owner know that the speakers have not been exposed to significant humidity, this is of cause not the case.


View attachment 505738

Could be also badly cleaned hand solder work.

 

[dfuller]

No, I was thinking more about what looks like white discoloration and dull surfaces on the circuit board's solder joints.

Flux residue and lead free solder.

 

[nat1]

I sold my KH 80's shortly after the warranty period expired, I don't regret that decision.

 

[Hasse]

I would be intrested to hear the analysis result from KH when it is available. Why did both speakers die in a similar way so close to each other in time?

 

[dfuller]

I would be intrested to hear the analysis result from KH when it is available. Why did both speakers die in a similar way so close to each other in time?

My guess, the caps were exposed to a very similar environment for a similar period of time. probably reached their limit pretty similarly.

 

[levimax]

Why did both speakers die in a similar way so close to each other in time?

That is what is concerning to me. With modern "quality control" (not the same thing as quality) products are being made very consistently and if there is a design flaw it can show up in most if not all of the products shipped. Compared to the past, with looser quality control methods and more "over engineering" to compensate for it, there was more variability with product reliability.

 

[respice finem]

My guess, the caps were exposed to a very similar environment for a similar period of time. probably reached their limit pretty similarly.

I think, when one out of a pair fails, it might make sense to send in both, for preventive exchange of the "culprit" components, before they fail on the other loudspeaker too. Same batch, same working hours, same room...

 

[RobL]

Coincidence? This former KH80 owner mentioned today in this post that his monitor died from a failed capacitor just after warranty…

Post in thread 'Neumann KH120 II Monitor Review'
https://www.audiosciencereview.com/...nn-kh120-ii-monitor-review.46362/post-2501139

I will give up on Neumanns for now. In my previous pair of KH80s with a KH750, one of the monitors broke just after the warranty ended, and the repair technician said that one of the capacitors had gone bad. Just too many issues with each pair

 

[Llund]

Hey everyone, trying not to hijack this. But one of my KH80's seems to have died today. It plays no sound, light on front functions as normal (red when turning on/off, solid white while on and idle) and it auto-sleeps like usual (light turns off). Not that it matters, but for easier explanation, the left speaker works and the right speaker does not. I have owned them for 5-6 years and they have been used daily. Never abused them. Have been turned on, with auto-off feature on, most of the time.

For a little while now, the right speaker has been behaving a little weird. Some times no sound, then a few tiny crackles. I initially thought this was my aging Mackie Big Knob, because of an incident with some red wine (please don't ask, haha!) years ago which made me stop using it for a good while. I since cleaned the Big Knob properly and function tested it a lot and it seemed to function well enough for me to start using it again a couple months back. When the right speaker would stop playing, I would wiggle some of the "known culprits" on the Big Knob (mono, mute and dim buttons) which I generally don't use. This would make the right speaker crackle (barely audible). Replugging the balanced jacks after some wiggling would usually make the right KH80 play sound again. But that didn't work today, and my headphones were still playing both channels. Meaning the problem is probably not the Big Knob or my Zoom UAC-2 audio interface. I tried bypassing the Big Knob, connecting directly to the UAC-2 with no luck.

I have a KH750 DSP sub, which the KH80's are connected to. I tried switching the L/R output cables on the 750, but only the left (working) speaker would play sound no matter what. Indicating the fault is not in the sub either. I tested the left speaker on the right side cables, and it works fine. Indicates the problem is with the right speaker.

I have opened up the right speaker and can not see anything obviously broken, no "burn marks" as in the images earlier in this thread. I took some photos, maybe someone with a keener eye can spot something?

Will it be worth it to get these repaired, or should I just cut my losses and look for something else?

Super bummed out by this. Thanks for any insight!

 

[AnalogSteph]

Haver you gone through this?

https://help.neumann.com/hc/en-us/articles/39978248897049-KH-Monitor-Troubleshooting

For starters, I would toggle all the DIP switches a few times when off, verify the input settings and perform a factory reset if none of that helped. If none of that brings your sound back, well then you have reason to worry. In that case I might investigate whether one of the small electrolytics near the DSP has anything to do with the reset circuitry, like maybe C194.

 

[Llund]

Haver you gone through this?......

Yeah I did that. Pretty sure I toggled all the switches too. Guess I could try once more, just to make sure. Also to be clear, I do not have enough knowledge about electronics to investigate any of what you mention. Thanks.

 

[Ktacos]

I've never felt so relieved to have sold a pair of speakers before. Can't see Nuemann responding to this publicly, companies are allergic to admitting fault.