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Neumann KH80DSP Teardown

Matias

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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 dB for each phase, that would mean what, -106 dB summed?

Edit: could they be doing the same to the outputs, use 4 of the 6 DAC channels to output 2 balanced signals, and input them to the TAS5613A chip amp?

https://www.cirrus.com/products/cs42526/
 
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chris719

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From 10 years ago with no actual data, yes.

They have a bad history but no one knows if these caps are fine or not. Further, capacitor life heavily depends on the conditions at which they are operated. Heavily de-rated and conservatively specified caps of marginal quality can outlive a good cap with high temp and ripple current stress.

I’m just not sure anyone can say with authority that these amps will have problems and when.
 

KSTR

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@restorer-john, anything on this board trigger any alarms? It's the AB tweeter amp from an Adam AX series I found on Adam's site (I own A5Xs.):

https://www.adam-audio.com/content/uploads/2016/09/adam-audio-technologies-tweeter-amp-1400x933.jpg
View attachment 134981
That's the one used in SX series (except for a brief period where it was replaced with an LM4780 composite I was mostly responsible for, but the LM4780 was discontinued quickly), designed by my then colleage at ADAM. And it's the tweeter amp which never outputs more than 10Watts continuous because of course a thermal limiter is engaging. The small TO-92 device on the far left is a themal sensor for the heatsink temperature and it shuts the thing off as an additional safeguard... which never happens, even when not attached to amp backplate.
Output transistors are Sanken 2SC3519Y and 2SA1386Y, btw. Genuine, of course (@restorer-john)
The photo was taken from a very early engineering prototype (the dual large output caps on the left are a tell that this is a Rev0 board), production models used high-grade 105°C long-life genuine japanese production throughout.
 

Mountain Goat

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That's the one used in SX series (except for a brief period where it was replaced with an LM4780 composite I was mostly responsible for, but the LM4780 was discontinued quickly), designed by my then colleage at ADAM. And it's the tweeter amp which never outputs more than 10Watts continuous because of course a thermal limiter is engaging. The small TO-92 device on the far left is a themal sensor for the heatsink temperature and it shuts the thing off as an additional safeguard... which never happens, even when not attached to amp backplate.
Output transistors are Sanken 2SC3519Y and 2SA1386Y, btw. Genuine, of course (@restorer-john)
The photo was taken from a very early engineering prototype (the dual large output caps on the left are a tell that this is a Rev0 board), production models used high-grade 105°C long-life genuine japanese production throughout.

How much worse are the AX boards? Should I up my fire insurance?
 

LTig

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In general, you can do much better with passive speakers and external amplifications. Noise floor will often be lower and you can get far more power.
I agree regarding measurements. The question though is audibility. Will a passive speaker with SOTA external amplification sound better than a DSP controlled active speaker at the same price?
 

astcal

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I agree regarding measurements. The question though is audibility. Will a passive speaker with SOTA external amplification sound better than a DSP controlled active speaker at the same price?

I have the same question. Especially with room correction capability from DSP.
 

restorer-john

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I agree regarding measurements. The question though is audibility. Will a passive speaker with SOTA external amplification sound better than a DSP controlled active speaker at the same price?

It's a loaded question, as it greatly depends on implementation, which varies from terrible to excellent across brands. There is no one answer to that, but it is a good question for sure.

For me, it's passive loudspeakers and excellent outboard amplification. But imagine if speakers had a standard amplifier buss where the manufacturer provided everything you needed to install and correctly implement a DSP/Amp section of your own? That would be a game changer IMO.
 

Markus @ Neumann

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Hello,

My name is Markus Wolff and I am the portfolio manager and technical coordinator for Neumann studio monitors.
I am not active in forums and usually do not comment in those. But I’d like to give some background information to some of the points mentioned in this thread from our point of view.
First, thanks to all of you for your comments and the constructive and fruitful conversation. I also very much appreciate the generally friendly and constructive way of communicating which is unfortunately not common at all.
A few words in advance before I come to some of the specific topics here. Sorry for the length of this contribution.
Our general philosophy regarding Neumann studio monitors is to provide professional loudspeakers for the audio engineer to enable them to judge audio material and to create statistically the best sounding and most reliable mixes. They provide the precision to immediately show any imperfection and sensitively show any changes in sound editing which leads to the least fatiguing working conditions.
The focus here is to concentrate on the real user benefit. The audio performance which can be achieved, the reliability even under the hardest studio conditions, consistency between different models and under different environmental conditions and the flexibility to integrate them in different environments.
The way this is done is what we see as our part.
Even though it is much appreciated by the marketing department to create stories about specific technical USPs which are relevant for the entire product portfolio (such as specific materials which are used, a certain driver arrangement or housing concept etc.), we use any technology which works best to achieve our goals even if it is different for every model. The USP is the user benefit as the best possible compromise between carefully weighted acoustical parameters. Marketing hates me for that .
A good example are the drivers that you can see on the picture. There is nothing spectacular visible. No die cast basket, no special coating, no unique cone material. The performance is what matters. It usually takes three years to develop a new driver. Every individual component is simulated in house and as a sum tailored to the needs in the specific model. The feedback loops between simulation, first samples, adapting simulation parameters to the real parameters and material properties and geometry to the simulation takes a long time. All components are individually produced on our own tools exclusively for Neumann. Visual appearance (despite the color black) has no influence.
During the project phase before every development stage the samples have to pass a 1000 hours full power test with different types of test signals. After that the loudspeaker has to behave identically to before in all acoustical parameters as well as with rattling and air tightness.
Regarding the power amplifier which there were some comments about: The performance stated in the data sheet of a component like this is important but does not necessarily reflect the overall performance when it is integrated in complex circuitry. This influences the overall performance significantly. The self generated noise and THD of the entire system shows that this is above what the chip itself is capable to deliver.
Also here: it is not the individual component or material that matters, it is the performance which can be achieved.
Regarding the specifically mentioned capacitors which we are using:
Capxon is one of the largest Taiwanese capacitor makers, they have fully automated processes, have automotive TS 16949 quality systems, supply major automotive companies, there is no evidence to conclude their quality is any lower than any other vendor at this time. There is anecdotal talk on the internet about this, much of this stems form an electrolyte quality incident about 15 years ago that impacted almost all Taiwanese vendors as they used the same sub supplier for the electrolyte, that does not represent the quality of the parts produced now as this issue has been solved. Regarding the apparent internet consensus here you also have to be mindful of the confirmation bias effect that occurs on the internet will tend to amplify a once legitimate quality issue for many years.
https://en.wikipedia.org/wiki/Capacitor_plague
In fact when looking at reports of capacitor failures on the internet, most will be the fault of the product design not the capacitor. It is the responsibility of the design engineers to use a part within its specification or with sufficient margin under its specification to ensure an appropriate lifetime for the product. Unfortunately, many volume consumer goods where Capxon is popular, may only calculate lifetime to the warranty period, using “typical” usage models, and will tend to fail prematurely.
Without calculating the expected lifetime of the part in the application you cannot assume a defective part. You can only assume a part is defective if it failed before the specified lifetime under the conditions in which it was used, this is not what we typically see in the reports.
As these are electro chemical devices the temperature and applied voltage has a huge impact on the lifetime. It is not uncommon to see a low cost 1000 hour part used at or very near its rated temperature and voltage where the expected lifetime is only going to be 1000 hours. Now consider the same brand capacitor but this time we choose a 5000 hour rated part and we ensure that in the system it operated a maximum temperature 25 degrees below its rated value, and 25% below its rated voltage under all conditions, in this case it can be expected to last >50,000 hours. Same brand of capacitor, but a 10 times higher expected lifetime, by design, this is how you ensure a reliable product, not by choosing one brand over another brand.
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.
I hope this could give you a rough insight into how we see and develop studio monitors.
Thanks a lot.
 
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pozz

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Hello,

My name is Markus Wolff and I am the portfolio manager and technical coordinator for Neumann studio monitors.
I am not active in forums and usually do not comment in those. But I’d like to give some background information to some of the points mentioned in this thread from our point of view.
First, thanks to all of you for your comments and the constructive and fruitful conversation. I also very much appreciate the generally friendly and constructive way of communicating which is unfortunately not common at all.
A few words in advance before I come to some of the specific topics here. Sorry for the length of this contribution.
Our general philosophy regarding Neumann studio monitors is to provide professional loudspeakers for the audio engineer to enable them to judge audio material and to create statistically the best sounding and most reliable mixes. They provide the precision to immediately show any imperfection and sensitively show any changes in sound editing which leads to the least fatiguing working conditions.
The focus here is to concentrate on the real user benefit. The audio performance which can be achieved, the reliability even under the hardest studio conditions, consistency between different models and under different environmental conditions and the flexibility to integrate them in different environments.
The way this is done is what we see as our part.
Even though it is much appreciated by the marketing department to create stories about specific technical USPs which are relevant for the entire product portfolio (such as specific materials which are used, a certain driver arrangement or housing concept etc.), we use any technology which works best to achieve our goals even if it is different for every model. The USP is the user benefit as the best possible compromise between carefully weighted acoustical parameters. Marketing hates me for that .
A good example are the drivers that you can see on the picture. There is nothing spectacular visible. No die cast basket, no special coating, no unique cone material. The performance is what matters. It usually takes three years to develop a new driver. Every individual component is simulated in house and as a sum tailored to the needs in the specific model. The feedback loops between simulation, first samples, adapting simulation parameters to the real parameters and material properties and geometry to the simulation takes a long time. All components are individually produced on our own tools exclusively for Neumann. Visual appearance (despite the color black) has no influence.
During the project phase before every development stage the samples have to pass a 1000 hours full power test with different types of test signals. After that the loudspeaker has to behave identically to before in all acoustical parameters as well as with rattling and air tightness.
Regarding the power amplifier which there were some comments about: The performance stated in the data sheet of a component like this is important but does not necessarily reflect the overall performance when it is integrated in complex circuitry. This influences the overall performance significantly. The self generated noise and THD of the entire system shows that this is above what the chip itself is capable to deliver.
Also here: it is not the individual component or material that matters, it is the performance which can be achieved.
Regarding the specifically mentioned capacitors which we are using:
Capxon is one of the largest Taiwanese capacitor makers, they have fully automated processes, have automotive TS 16949 quality systems, supply major automotive companies, there is no evidence to conclude their quality is any lower than any other vendor at this time. There is anecdotal talk on the internet about this, much of this stems form an electrolyte quality incident about 15 years ago that impacted almost all Taiwanese vendors as they used the same sub supplier for the electrolyte, that does not represent the quality of the parts produced now as this issue has been solved. Regarding the apparent internet consensus here you also have to be mindful of the confirmation bias effect that occurs on the internet will tend to amplify a once legitimate quality issue for many years.
https://en.wikipedia.org/wiki/Capacitor_plague
In fact when looking at reports of capacitor failures on the internet, most will be the fault of the product design not the capacitor. It is the responsibility of the design engineers to use a part within its specification or with sufficient margin under its specification to ensure an appropriate lifetime for the product. Unfortunately, many volume consumer goods where Capxon is popular, may only calculate lifetime to the warranty period, using “typical” usage models, and will tend to fail prematurely.
Without calculating the expected lifetime of the part in the application you cannot assume a defective part. You can only assume a part is defective if it failed before the specified lifetime under the conditions in which it was used, this is not what we typically see in the reports.
As these are electro chemical devices the temperature and applied voltage has a huge impact on the lifetime. It is not uncommon to see a low cost 1000 hour part used at or very near its rated temperature and voltage where the expected lifetime is only going to be 1000 hours. Now consider the same brand capacitor but this time we choose a 5000 hour rated part and we ensure that in the system it operated a maximum temperature 25 degrees below its rated value, and 25% below its rated voltage under all conditions, in this case it can be expected to last >50,000 hours. Same brand of capacitor, but a 10 times higher expected lifetime, by design, this is how you ensure a reliable product, not by choosing one brand over another brand.
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.
I hope this could give you a rough insight into how we see and develop studio monitors.
Thanks a lot.
Markus, welcome to the forum. I'm glad that you took the time to add your perspective.

Can you say a few words about how you achieve such tight tolerances in the final product? What happens in the production stage when a supplier changes or a part is no longer available (e.g., for the power supply)?
 

kipman725

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CapXon may have improved since then but my experiences relate to products made within the last 10 years. Failures in the product started to occur at 2 years. A statistically significant sample of the product where found to have failed due to CapXon capacitors. The CapXon capacitors where used within specification. I'm just a random voice on the internet and can't (for obvious reasons) supply you with more infomation to back up my claims but would strongly caution you on using them.
 

Matias

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@Markus @ Neumann welcome to the forum! Very nice having a representative reading and answering here.
 

dfuller

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Guess we'll find out in time whether to add them to the badcaps list or not. But Neumann using cheap capacitors is clearly not a good look.

I wouldn't buy anything with crap capacitors in it. Don't care what it is, it doesn't come into my house.
I took one of my 310s apart the other day and those boards are all Yageos (470uF/400V on the SMPS primary side) and various Japanese brands (everything else). It's just this one. Presumably they had to reduce costs on these somehow because they're far, far cheaper ($1000/pr vs $4400/pr and these use more expensive DSP instead of analog active). Regardless, if Neumann has done their homework (which they have), it won't be a problem.
 

JohnYang1997

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CapXon may have improved since then but my experiences relate to products made within the last 10 years. Failures in the product started to occur at 2 years. A statistically significant sample of the product where found to have failed due to CapXon capacitors. The CapXon capacitors where used within specification. I'm just a random voice on the internet and can't (for obvious reasons) supply you with more infomation to back up my claims but would strongly caution you on using them.
I suggest you read that comment again.
 

restorer-john

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@Markus @ Neumann Thanks for your interest in our teardown thread. :)

The question I ask is why does Neumann compromise with CapXon in the first place? Surely one of your points of difference is quality of construction and reliability? CapXon does not in any way instill confidence and for very good reason.

Why not use Panasonic, Elna, Rubycon, Nippon Chemicon or Nichicon? They are all better choices. A few cents extra per component and you could shout about how good your caps are, instead of going into damage control and writing a 1000 word (1018 actually) essay, everytime someone exposes the cost cutting.
 
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Doodski

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I've replaced a lot of capacitors over the years. The worst applications where they failed was in high density small sealed enclosures with little to no venting. We've been discussing the use of class AB and D amplifiers in active speakers for some time here at ASR. We've also been discussing the possible failure rate of capacitors used in the active speaker enclosures as well as mechanical PCB/solder failure due to vibration stress inside the speaker cabinet. This use of CapXon/other cheap caps with a shoddy record of reliability is going to backfire if they fail en mass like us techies and engineers have seen happen in audio gear, video gear and other stuff. It makes no sense to any person who has replaced many capacitors and have seen a pattern of brands and applications where the failures have occurred. :facepalm:
 

DJBonoBobo

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@Markus @ Neumanngoing into damage control and writing a 1000 word (1018 actually) essay, everytime someone exposes the cost cutting.

The way I see it, the only damage so far has been done by you making statements here that can damage the trust of customers (like me) in a brand. When I asked you to explain them, you didn't, but left it at "murmuring" about brands. At the same time, you seem to make fun of the fact that a representative of one of the best and most respected manufacturers in the world takes the time to respond to you in detail. It is always easier to make any claims than to then respond to them.
I think it's interesting and also legitimate when someone points out possible problems, but as long as you don't have any proof or even a theory whether this is even relevant for the customer, I think it's important to frame it in an understandable way. As a customer, I only want to be irritated if there are serious reasons for it. :)
 

somebodyelse

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I've replaced a lot of capacitors over the years. The worst applications where they failed was in high density small sealed enclosures with little to no venting. We've been discussing the use of class AB and D amplifiers in active speakers for some time here at ASR. We've also been discussing the possible failure rate of capacitors used in the active speaker enclosures as well as mechanical PCB/solder failure due to vibration stress inside the speaker cabinet. This use of CapXon/other cheap caps with a shoddy record of reliability is going to backfire if they fail en mass like us techies and engineers have seen happen in audio gear, video gear and other stuff. It makes no sense to any person who has replaced many capacitors and have seen a pattern of brands and applications where the failures have occurred. :facepalm:
Knowing how often humans make unjustified leaps between correlation and causation, let alone see correlations that don't actually exist, I'd like to see some evidence that the caps are failing earlier than their ratings would suggest given the operating conditions, and that caps of the same specification from other manufacturers would last longer under the same conditions. An alternate explanation is that people who design products to barely scrape through warranty periods so they can reduce costs also pick the cheapest supplier that will reliably meet the spec, not the premium brand. If Neumann are achieving the same performance and lifetime with a lower cost component that's good engineering and something to be praised. I guess we'll find out who's right over the next few years, but so far I've not heard of a rash of KH80 failures.
 

restorer-john

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The way I see it, the only damage so far has been done by you making statements here that can damage the trust of customers (like me) in a brand. When I asked you to explain them, you didn't, but left it at "murmuring" about brands. At the same time, you seem to make fun of the fact that a representative of one of the best and most respected manufacturers in the world takes the time to respond to you in detail. It is always easier to make any claims than to then respond to them.
I think it's interesting and also legitimate when someone points out possible problems, but as long as you don't have any proof or even a theory whether this is even relevant for the customer, I think it's important to frame it in an understandable way. As a customer, I only want to be irritated if there are serious reasons for it. :)

It is Neumann who are using cheap, third rate capacitors, known for catastrophic failure and poor reliability, not me. I just clean up the mess years later and recount my experience. I have no axe to grind.

It's their name on the reputation chopping block, not mine. I don't care one way or the other. It's just disappointing, that's all, as when it all falls in a putrid heap, they will be flailing around, crying and wailing, just like VW and all the others who tried to pull the wool over their customers' eyes.

I wouldn't touch CapXon with a 10ft barge pole, letalone attempt to justify my decision to cut costs and justify putting, cheap, unreliable components in my so-called "premium" product.

Put top tier brand components in your gear or don't build it at all!
 

DJBonoBobo

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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.
just like VW and all the others who tried to pull the wool over their customers' eyes.

So you mean that installing components that meet certain test criteria, but that are not from a premium manufacturer (which is what Neumann did), is comparable to deliberately faking performance features (as VW did)?

Maybe it will turn out that you, with your experience, know better than Neumann with all their tests, but until then you maybe should watch your choice of words a bit?
 
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