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Neumann KH120 Disassembly Pictures

LTig said:
Neumann specs an aluminium enclosure.

Edit: I do think however that the visible front baffle is made of a kind of molded plastic. For my O300D it's called LRIM which stands for Low Resonance Integral Moulding. This plastic baffle may be mounted on top of an aluminium baffle.
Click to expand...

You are correct, the inside of the front baffle is molded plastic. It would make sense for an outer layer to be thin aluminum precision molded for the waveguide that is attached to an inner plastic support structure. The remaining 90% of the enclosure contains integral features consistent with molded plastic.

Does the rest of the enclosure have the cold feel of metal?

The knee jerk reaction in defense of manufacturer is rather ironic coming from a forum that freely labels companies and individuals as "snake oil" salesmen.
 
texbychoice said:
You are correct, the inside of the front baffle is molded plastic.
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Wrong.
It is obvious that the tapped holes are into metal, presumably the aluminium specified.
The unaccustomed may confuse painted die cast metal with plastic I suppose.

Why would Neumann lie about this and why would ignorant people open their mouths and jam their foot in, figuratively speaking?
 
it's not like they ever claimed an aluminum casing improves the sound. the kh 80 is almost completely devoid of resonances too and it's made out of plastic. there's no reason to even lie about it
 
LTig said:
Neumann specs an aluminium enclosure.

Edit: I do think however that the visible front baffle is made of a kind of molded plastic. For my O300D it's called LRIM which stands for Low Resonance Integral Moulding. This plastic baffle may be mounted on top of an aluminium baffle.
Click to expand...

The LRIM stuff is mentioned in the description of the KH420, however the KH120 page states aluminum explicitly. The KH120 is the oldest revision of them all I think, so perhaps they've decided to go with the polycarbonate and when we get the KH120 DSP it will be plastic as well.

Not that it matters. I have KH80s and the polycarbonate is a dense, durable material. We know from the (exhaustive, lol) measurements that there are no resonances and that's the only important thing as far as I'm concerned.

q3cpma said:
It's clearly written "Aluminium" in the third picture and the last one makes it clear it's some kind of metal. Actually, why am I even replying to a troll?
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Yeah I dunno we go the rounds with random trolls who signed up to talk shit about world-class active speakers every other day on ASR :p
 
texbychoice said:
Amazon description claims non resonant Aluminum enclosure. That is a blanket statement not backed by fact. Can't tell for sure from the pictures here, but the enclosure does no have the look of Aluminum. Push on connectors soldered soldered in place is not good engineering or attention to detail. Pretty nice looking PC, but numerous components and locations for failures. All that complexity just to produce a good looking graph, therefore the sound must be great? Spend the same, or less, on quality (more reliable) passive speakers and you won't hear any difference.
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I’m so confused why you don’t think it’s aluminum as its very reputable manufacturer has consistently specified for the past decade, along with the aluminum symbol in the molding o_O it’s not like we’re dealing with AudioQuest here.
Both parts of the case are 100% aluminum, I’ve spent more time fondling mine than I may want to publicly admit... however, they are coated in rather industrial paint, so maybe that’s where the confusion is coming from?

With regards to reliability, I’m not an EE, just a software engineer, but these seem to have an excellent reliability track record over the 10 years they’ve been out. And they use reputable well-specced parts, especially important for the electrolytic capacitors, which are a common source of failure in cheaper monitors. Reliability was definitely a top design concern.

Yes, the PCB could be a lot simpler if they used DSP, but keep in mind these monitors were released in 2010, and who knows how many years the development took before that? They went with an analog design because they felt it was the better choice with what components were available at the time for the target price point, and it’s hard to argue with the results, being that it’s still one of the best performers in its class 10 years later.
 
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They don't look like Genelec RAW. What is even that Neumann company, definitively must be hoax. As everyone knows, aluminium couldn't be painted ;)
raw_tuote.jpg


By the way polycarbonate is high-end plastic. Better quality compared to most of other polymers. Very durable to impact and temperature. Polycarbonate film capacitors were one of the best type of capacitors available back in the days. Unfortunately they were hard to manufacture and production stopped some years ago.
 
I opened one of my units when it stopped working. Then sent it to the Sennheiser (plus Neumann) service center in Bombay. I was told there is some issue in the SMPS, and they wanted to change the entire plate amp, which i refused and asked them to diagnose the issue. Eventually (i dont think they did any real work) i had to pay for a new plate. They then took my second unit and said they will calibrate both to specs and send them back.

I have not been able to use them much, but they 'sounded' fine.

It seems Neumann Philisophy is 'replace' rather than diagnose and repair.

-vin
 
soundtrane said:
I opened one of my units when it stopped working. Then sent it to the Sennheiser (plus Neumann) service center in Bombay. I was told there is some issue in the SMPS, and they wanted to change the entire plate amp, which i refused and asked them to diagnose the issue. Eventually (i dont think they did any real work) i had to pay for a new plate. They then took my second unit and said they will calibrate both to specs and send them back.

I have not been able to use them much, but they 'sounded' fine.

It seems Neumann Philisophy is 'replace' rather than diagnose and repair.

-vin
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I operated as a electronic/mechatronics technician for ~15 years and it was a sad period when the electronic repair shops where closing due to uneconomical repairs coming in the door and the manufacturers not providing replacement parts. I managed to keep operating when the majority of electronic shops closed and so I consider myself lucky that way but it is the way it is now. Parts are not available or they are difficult to source and the economics of parts means it is often better to replace the unit or the PCB(s). If the new laws being considered are set in place we may again have replacement parts and service literature. That would be very good for all involved.
 
soundtrane said:
What new laws, if i may ask?
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The Canadian federal government is planning some sort of regulation/laws that will force the companies/manufacturers to provide service manuals and at least commonly replaced parts. They've been mentioning this for some time and I think with all the in-country issues and global issues they simply have not had the time to address this stuff.
 
Say, has anybody taken the grille off the tweeter? I don't have any spares around otherwise I'd try it out.
 
Tweeter grille is not acoustically transparent, actually Neumann taken this into account and used it to fine-tune speakers.
If you look closely there is dent on center of grille with small piece of foil acting like phase plug or something.
So removing grille from tweeter would probably break tuning of speakers and make things worse.
 
They wanna know what the tweeter is made of rather than optimize it.
 
It is not an secret - 25mm alloy-fabric dome tweeter.
Exact alloy material isn't disclosed by Neumann themselves but if I recall correctly it is sometimes referred as titanium in other sources.
 
soundtrane said:
I opened one of my units when it stopped working. Then sent it to the Sennheiser (plus Neumann) service center in Bombay. I was told there is some issue in the SMPS, and they wanted to change the entire plate amp, which i refused and asked them to diagnose the issue. Eventually (i dont think they did any real work) i had to pay for a new plate. They then took my second unit and said they will calibrate both to specs and send them back.

I have not been able to use them much, but they 'sounded' fine.

It seems Neumann Philisophy is 'replace' rather than diagnose and repair.

-vin
Click to expand...

Someone may end up doing a diagnosis on the failure as part of their job but unlikely the same person that you would be interacting with. They would have to identify the problem, repair it and then check to make sure everything else was still to spec in the circuit. Probably best to just have a new plate amp.

Personally I repair a lot of electronics but I can see how it is more difficult to do so economically.
 
Hello everybody,

I have a SMPS of one KH120A that broke recently. I send it to Neumann service and they proposed to change main board for 200 euros more than the price of a new speaker.

I'm thinking buying only the main PCB and change it by myself but i wonder if each PCB is calibrated independantly for each speakers and if i will need to adjust screws on the main board? Or are the calibration screws here to calibrate the main board itself?

Thanks a lot if you have the answer!
 
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