Neumann KH80DSP Teardown

[solawind]

If they break down during the warranty period, then Neumann is only taking themselves for fools.

If they break down right after the warranty period, that's skill.

So my KH80 has refused to turn on today , just half year after warranty end date. Power LED do not lit. Intending to disassemble it and check those trash neumann capactiors you guys were talking about

 

[iamrackman]

Hello everyone! I have been visiting and reading the forum as a guest for years but I have decided to make my first post.
By the way, what you guys do is great! In the end.

Unfortunately, one of my KH80 AG US studio monitors is malfunctioning. It lights up, the LED goes from red to white, OK, but then starts making strange noises or nothing.

These were won in a Neumann mixing competition in 2023.
The firmware is at the latest version: 1.3.6

Things I tried:
I changed the power cable.
I tried different electrical outlets.
I tried in different rooms and at friends' houses.
I did a factory reset.
I tried with Cannon cables, Plug cables, and no audio cables.
I changed the local setting to network.
I used MA 1 with its corresponding microphone.
I took the device to the authorized technician in my country (Argentina) (I waited two months, and they told me there was nothing wrong with it).
I spoke with Neumann agents.

None of them were able to give me a logical and accurate answer.

Any ideas? Sorry for my english

Video link

 

[AnalogSteph]

I took the device to the authorized technician in my country (Argentina) (I waited two months, and they told me there was nothing wrong with it).

?!

Your problem sounds like a pretty hard fault, I don't get how it could turn into a no fault found elsewhere. Unless... is your location particularly hot, cold or humid by any chance? Or does your mains voltage have a habit of going out of spec? Obviously this may simply have been the service center's way of load-shedding, in which case you would simply have been lied to.

Had a look at the video... that's wild. Since you can apparently provoke the most random behavior by momentarily turning off/on the power, there are two avenues I would want to investigate:
1. The power-on reset circuitry for the DSP section. It almost seems to me that the unit often powers up in an undefined state. Could be a pesky little SMD electrolytic capacitor in the delay that's called it quits.
2. Stability of digital power supplies.

You need a good, reliable electronics tech who'll work on modern(-ish) electronics with surface mount components, and ideally a service manual (no clue whether Neumann would provide it to you, but asking won't hurt). You have been given the runaround for way too long.

 

[iamrackman]

?!

Your problem sounds like a pretty hard fault, I don't get how it could turn into a no fault found elsewhere. Unless... is your location particularly hot, cold or humid by any chance? Or does your mains voltage have a habit of going out of spec? Obviously this may simply have been the service center's way of load-shedding, in which case you would simply have been lied to.

Had a look at the video... that's wild. Since you can apparently provoke the most random behavior by momentarily turning off/on the power, there are two avenues I would want to investigate:
1. The power-on reset circuitry for the DSP section. It almost seems to me that the unit often powers up in an undefined state. Could be a pesky little SMD electrolytic capacitor in the delay that's called it quits.
2. Stability of digital power supplies.

You need a good, reliable electronics tech who'll work on modern(-ish) electronics with surface mount components, and ideally a service manual (no clue whether Neumann would provide it to you, but asking won't hurt). You have been given the runaround for way too long.

Hi @AnalogSteph,

Thanks for taking the time to reply. To give more context, the monitor (currently the right side) was working perfectly until 3 months ago, then these strange noises started.

My studio isn't hot, humid, or cold. The left monitor actually works perfectly.
I've tried other power outlets, and they reproduce the same error. I'm attaching a screenshot of my UPS, which they're now plugged into.
In my opinion, I don't think the problem comes from that side. I've also used two monitors at my friend's studios and a friend's house.

I have other monitors available in the studio, and they all work perfectly; of course, they don't have DSPs.

What you said about the SMD capacitor seems more logical to me.

Unfortunately, the official Neumann service center in my country "didn't detect a problem with the monitor," which seems like a joke to me.
Honestly, if they didn't "see anything," I don't really know what to think. I also imagine they didn't open the monitor.
I'm afraid to take it to a non-official service center, even though I understand the warranty must be expired.

I've written to Neumann again, but their responses are silly. I imagine Neumann has never had a case like this.

The situation is truly frustrating. Is it a poltergeist case?!

Other video: https://drive.google.com/file/d/1SrZR8ruyMQPhN2QbIvOAmAO-Kxcv93Nb/view?usp=sharing

 

[OldSlowDude]

I thought I’d chime in with my own experience.
I’ve had my KH80s for about four years. After around three years, the right speaker started popping. A while later, the left speaker gave a loud POP and stopped working entirely. I can’t say for certain it was the capacitors (though in my layman’s opinion it seemed likely), and I was a bit disappointed, to say the least.

I’m sorry to hear some people have had bad experiences with customer support. I can only share my own — and maybe it comes down to getting in touch with the right people and a bit of luck.

I contacted Neumann directly, and I have to say the support I received from Sennheiser on this issue was outstanding. They replaced both units without even seeing the old ones first and allowed me to send the faulty ones back afterwards. Of course, it would have been better if they hadn’t broken at all, but it’s reassuring to know their customer service is so good if something does go wrong.

If you have problems with the KH80, I’d recommend contacting Neumann online politely and directly — it worked wonderfully for me.

All in all, I’m still happy with the speakers and the purchase — and they still sound great.

 

[Dhpaladin]

I thought I’d chime in with my own experience.
I’ve had my KH80s for about four years. After around three years, the right speaker started popping. A while later, the left speaker gave a loud POP and stopped working entirely. I can’t say for certain it was the capacitors (though in my layman’s opinion it seemed likely), and I was a bit disappointed, to say the least.

I’m sorry to hear some people have had bad experiences with customer support. I can only share my own — and maybe it comes down to getting in touch with the right people and a bit of luck.

I contacted Neumann directly, and I have to say the support I received from Sennheiser on this issue was outstanding. They replaced both units without even seeing the old ones first and allowed me to send the faulty ones back afterwards. Of course, it would have been better if they hadn’t broken at all, but it’s reassuring to know their customer service is so good if something does go wrong.

If you have problems with the KH80, I’d recommend contacting Neumann online politely and directly — it worked wonderfully for me.

All in all, I’m still happy with the speakers and the purchase — and they still sound great.

Well looks like one of my 5yr old KH-80 (not used since Covid though) is malfunctioning. I can configure it via MA-1 but no sound output. Factory reset, firmware upgrade didn’t help. Swapping speakers confirms it is the monitor and not cabling/setup.

I’ve contacted Neumann - waiting to hear back. It’s been 2 days. Not looking forward to paying $$ to repair these - I’ve hardly used them.

 

[sabin]

Hello everyone, I've been browsing ASR for a while but today is my first post here, I have bought a pair of KH80 on the 23.03.2025 and today one of my speakers seems to have broken down, it emits a loud pop sound every now and then regardless of playing anything or not, regardless of being plugged in or not, and doesn't go into protection.

It makes loud pops which are kinda scary and seem like they're almost breaking the speaker. After some troubleshooting and evaluation me and some of my online friends decided it's something of the nature of " either the amp, caps, power supply, or everything at once". I've contacted neumann through their online page today and hopefully I get an answer tomorrow, I should be covered.

S/N: 6124475483
Here's a video showcasing the issue

 

[tyanlion]

Well looks like one of my 5yr old KH-80 (not used since Covid though) is malfunctioning. I can configure it via MA-1 but no sound output. Factory reset, firmware upgrade didn’t help. Swapping speakers confirms it is the monitor and not cabling/setup.

I’ve contacted Neumann - waiting to hear back. It’s been 2 days. Not looking forward to paying $$ to repair these - I’ve hardly used them.

Any info on how much it cost to repair them?

 

[Dhpaladin]

Any info on how much it cost to repair them?

They wanted me to send it in and then give me an estimate. I decided to just sell it for parts. Not gonna deal with kh80 ever again. Though their customer support is great.

 

[tyanlion]

They wanted me to send it in and then give me an estimate. I decided to just sell it for parts. Not gonna deal with kh80 ever again. Though their customer support is great.

Oh man I'm kinda scared now about mine it'll becomes a 700usd+ paper weight if anything goes wrong

 

[Azrael]

The port tube is of a curious design - There is a small hole in the middle of it blocked by the same material which stuffs the upper part of the cabinet! I'll leave it to someone savvier in these things to explain this.

and

Shorter wavelengths/higher frequencies will exit through the hole and be attenuated by that porous/fibrous material. Longer wavelengths will move past it and exit the end of the tube.

Thank you very much for this image in particular. I am always looking for effective methods to suppress longitudinal resonances in bass reflex ports. This seems to be a simple but very effective way of achieving this. The KH80 has been tested here (and was subsequently measured several times), but unfortunately without near-field measurements of the port and the drivers. However, the ports of the KH120 are basically identical in design, so I am showing the following graphic from this review:

 

[AnalogSteph]

Thank you very much for this image in particular. I am always looking for effective methods to suppress longitudinal resonances in bass reflex ports. This seems to be a simple but very effective way of achieving this.

It's nifty, isn't it? You're basically placing a damped leak exactly where the problematic resonance's pressure maximum is. My gut feeling says that air at the intended tuning frequency is just flowing along without too much pressure involved most of the time, so it won't overly mind if a small part of the wall is more of a suggestion. (Homework: Keeping the affair from fluttering at high port velocities.) The longitudinal resonance with its velocity maxima at the ends and pressure maximum in the middle is going to be a lot more peeved. Acoustic stuffing at the ends would have a similar effect but also impede airflow at the same time, so that's a less attractive approach.

How-to kill unwanted port resonances?

Ports have a 'wanted' fundamental Helmholtz resonance but also have unwanted resonances that can usualy be classed as open-ended, closed-ended pipe resonances or internal enclosure standing wave leak-through. I thought it might be interesting to compile a thread of all known methods, good and...

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