Is this how Neumann KH80 speakers die?

[solderdude]

I meant the SMD IC with the 8 pins that is close to it.
The one where the red arrow in post #11 points to. (U100 on the PCB).

It is missing the topside with the type number on it as that exploded off but on the other one that blew up the IC was still readable I think.

Judging from the exploded cap it is likely more components may have been destroyed that isn't evident from the outside making it almost impossible to fix without the actual schematics.

 

[m_g_s_g]

Either these really don't like your mains or there's something else afoot.

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,...).

I meant the SMD IC with the 8 pins that is close to it.

Oh, sorry: L6565D

NEWS: I reopened the L speaker, the last one that failed some days ago. As (now all of us) expected, the very same capacitor shows signs of failure (less than for the R speaker, probably because this time I broke my own record for cutting-power-after-speaker-spark-emission).

 

[solderdude]

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.

Most likely scenario is the poor quality of the exploded caps setting this all in motion.
What usually happens is that due to higher temperatures such capacitors, that are the reservoir caps after the rectifier, get an increased ESR resulting in high peaks resulting in more gas inside the caps and finally exploding. The caps appear to be 105 degrees but suspect the manufacturer skimped on quality.
With that usually also comes a higher output voltage (peaks) that may even destroy parts further down.
When the cap went it may have shorted and overloaded the primary circuit blowing it up.

 

[markstein]

@Markus @ Neumann: Any comment from the manufacturer?

You were defending the use of inexpensive capacitors in the thread linked below, now the fears expressed at the time seem to have been confirmed, at least in some cases.

Are smaller Neumann speakers designed to less quality standards than the more expensive ones (KH420, KH310) regarding electronics used?

Quote from your post in thread 'Neumann KH80DSP Teardown'

"All electrolytic capacitors used by Neumann are de-rated for a >10 year lifetime under a harsh usage model that far exceeds the expected normal use for the product. This is how we ensure the reliability and quality of our products."

Neumann KH80DSP Teardown

Also interesting that they went with Cirrus Logic CS42526 chip to do both 2 channel ADC and 6 channel DAC functions with it. As they mention in the description of the speaker, they used both ADC channels to digitize the XLRs + and - signals separately, and sum them digitally. ADC THD+N is -100...

www.audiosciencereview.com

Edit: Seems that also KH120 II have issues:

Post in thread 'Neumann KH120 II Monitor Review'

Neumann KH120 II Monitor Review

If you need deeper bass, have space and budget, then KH150 is your speaker. i have the small room to listen speaker，so i think the size kh120 is limit to me

www.audiosciencereview.com

 

[RobL]

3rd tier caps in such a stellar monitor are such a sad concession to the bean-counters.

 

[G|force]

If I had these and they were working normally but out of the warranty period, I would definitely swap out the caps ASAP.

 

[Sokel]

@Markus @ Neumann: Any comment from the manufacturer?

You were defending the use of inexpensive capacitors in the thread linked below, now the fears expressed at the time seem to have been confirmed, at least in some cases.

Are smaller Neumann speakers designed to less quality standards than the more expensive ones (KH420, KH310) regarding electronics used?

Quote from your post in thread 'Neumann KH80DSP Teardown'

"All electrolytic capacitors used by Neumann are de-rated for a >10 year lifetime under a harsh usage model that far exceeds the expected normal use for the product. This is how we ensure the reliability and quality of our products."

Neumann KH80DSP Teardown

Also interesting that they went with Cirrus Logic CS42526 chip to do both 2 channel ADC and 6 channel DAC functions with it. As they mention in the description of the speaker, they used both ADC channels to digitize the XLRs + and - signals separately, and sum them digitally. ADC THD+N is -100...

www.audiosciencereview.com

I like Neumann, I really do if I don't own one.
But WTF???

Even newbies know the reputation of these caps, there's no excuse whatsoever for seasoned engineers (I hope, and I also hope the electronics inside are not assigned to some obscure company)

About price? Put whatever scale you like, but I dare anyone to gut not some hi-end BS gear but just one of these cheapo, old plastic Sony all-in ones "stereo" with the double decks, CD, radio, etc.
A sea of ELNA and Nichicon inside, up to spec even after 20 years of teenage parties and thrown unused for years at a dumpster.

No excuse at all.

 

[EngineerNate]

@Markus @ Neumann: Any comment from the manufacturer?

You were defending the use of inexpensive capacitors in the thread linked below, now the fears expressed at the time seem to have been confirmed, at least in some cases.

Are smaller Neumann speakers designed to less quality standards than the more expensive ones (KH420, KH310) regarding electronics used?

Quote from your post in thread 'Neumann KH80DSP Teardown'

"All electrolytic capacitors used by Neumann are de-rated for a >10 year lifetime under a harsh usage model that far exceeds the expected normal use for the product. This is how we ensure the reliability and quality of our products."

Neumann KH80DSP Teardown

Also interesting that they went with Cirrus Logic CS42526 chip to do both 2 channel ADC and 6 channel DAC functions with it. As they mention in the description of the speaker, they used both ADC channels to digitize the XLRs + and - signals separately, and sum them digitally. ADC THD+N is -100...

www.audiosciencereview.com

Edit: Seems that also KH120 II have issues:

Post in thread 'Neumann KH120 II Monitor Review'

Neumann KH120 II Monitor Review

If you need deeper bass, have space and budget, then KH150 is your speaker. i have the small room to listen speaker，so i think the size kh120 is limit to me

www.audiosciencereview.com

The caps can be specced however Neumann wants but if the "10 year" rating is based off cap manufacturer claims that aren't worth the paper they aren't printed on then it too is meaningless.

Not really any excuse to use lowest common denominator caps in a premium product.

 

[DSJR]

Can Neumann take the boards and either replace them, or maybe repair*? The speakers are still current, so boards should be readily available surely?

* I've seen a couple of vids concerning audio products once made by a prestigeous maker but using now temperamental smps once claimed to improve performance. Said smps can fail now and in one case, a blow-up took a good bit of the following circuit with it. It was eventually fixed, but much head scratching and hand wringing went into the repair (the ,maker doesn't want to know).

 

[Chr1]

Jeez. I will be interested in seeing what goes into the new KH310 (MK2?)

I bought a pair of KH310s several years ago. But only after spending a fair amount of time looking into any possible reports of their reliability online. (No sign of anything untoward by all accounts thankfully.)

I wonder if this dubious cost cutting occurs on all newer Neumann products, or just the cheaper end of their product line.

Very disappointing either way IMO.

 

[respice finem]

My takeaway from this is, not to buy "black boxes" = loudspeakers without availability of a service manual.
Loudspeakers are not "disposable" devices, like cheap mini-amps.

 

[markstein]

Loving my old KH120, KH310 and KH810. Very reliable speakers. Other than a very early blow-up of one of my KH810 amps during warranty phase no issues at all.

Without wanting to over-dramatize isolated incidents, it nevertheless seems that Neumann saves pennies in their recent BOM of speaker electronics parts, compromising long term reliability, at least for lower cost speakers. I for myself would be happy to pay a little more and be sure that only top quality ingredients (caps) are used...

Time to consider Genelec when updating/upgrading my speakers?

 

[Hasse]

I am for sure no expert, but from the pictures, the PCB seems to be quite corroded, also on other parts than close to the centrum of damage.
Can it be so that theese speakers have been subjected to high humidity over time, leading to corrosion, and maybe been part of the failure?

 

[m_g_s_g]

[...] the PCB seems to be quite corroded [...]

I don't see the PCBs "quite corroded". Maybe you are referring to the brownish-clear glue that sticks the capacitors to the PCB?

 

[suttondesign]

I use kh80’s in my converted garage home office. I am in WA near the Canada border. Anyone have a suggestion what I should do? I bought them from Vintage King.

 

[m_g_s_g]

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.

 

[Digby]

Loudspeakers are not "disposable" devices, like cheap mini-amps.

Why should any audio product be disposable in this way? I recycle as much of my packaging and rubbish as I can, only for this kind of product to be thrown away after the usable lifespan (10 years or so, if you are lucky), when it should be an easy fix for a product that could potentially last 50 years (whether amplifier or speaker), save for manufacturers deliberately withholding schematics.

 

[Sokel]

I use kh80’s in my converted garage home office. I am in WA near the Canada border. Anyone have a suggestion what I should do? I bought them from Vintage King.

Recap them, ASAP.
If the el. caps inside are of those Capxon kind, it's an accident waiting to happen.

Changing them seems as easy as it gets if you solder stuff, their positioning makes it easy.
The only thing that needs some attention is this glue, better warm it a little before removing it if it's of the soft kind.

 

[respice finem]

Why should any audio product be disposable in this way? ...

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.

 

[EngineerNate]

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 expect first rate customer service from Neumann, this is good to hear though.