apzx
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Neumann KH120A Tweeter Crackling Issue
- Thread starter apzx
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Help Support GroupDIY Audio Forum:
The KH-120a have their fare share of problems ,
Sure they work just fine inside the warranty period ,
then at some point down the line they become problematic ,
Theres definately a few more posts around here relating to the issues people have had .
I was in the hifi and dj equipment trade a little over 20 years ago , just when SMPS powered speakers started hitting the shelves , it didnt take long before reliabillity issues became apparent .
Perhaps you have a tweeter with a damaged voice coil , maybe swapping the tweeters over might eliminate or reveal the issue .
Chances are now Neumann wont even offer to service them , in any case the cost when they did was outrageous ,they might offer you a concession on a new pair , but your buying back into the same trap again .
Sure they work just fine inside the warranty period ,
then at some point down the line they become problematic ,
Theres definately a few more posts around here relating to the issues people have had .
I was in the hifi and dj equipment trade a little over 20 years ago , just when SMPS powered speakers started hitting the shelves , it didnt take long before reliabillity issues became apparent .
Perhaps you have a tweeter with a damaged voice coil , maybe swapping the tweeters over might eliminate or reveal the issue .
Chances are now Neumann wont even offer to service them , in any case the cost when they did was outrageous ,they might offer you a concession on a new pair , but your buying back into the same trap again .
Mine had a faulty TDA7293 and various issues with the SMPS.
Prior to that I had another one with blown SMPS, perhaps cause by the same issue. I sent it to Sennheiser UK for repair
I have read online about noise and crackling issues caused by bad electrolytic capacitors.
You should probably inspect further with oscilloscope and potentially consider recapping.
Nice sounding speakers but quite unreliable in my experience. I wonder if the larger models are problematic as well.
Prior to that I had another one with blown SMPS, perhaps cause by the same issue. I sent it to Sennheiser UK for repair
I have read online about noise and crackling issues caused by bad electrolytic capacitors.
You should probably inspect further with oscilloscope and potentially consider recapping.
Nice sounding speakers but quite unreliable in my experience. I wonder if the larger models are problematic as well.
If you
- eliminate the driver as above,
- eliminate the PSU rails as measured ON the pcb,
- inspect any interconnects, contacts on both sides
- gentle pressure with bamboo skewer or chopstick to find a partial connections,
then you can try some “fire and ice” to isolate a bad area of components, or hopefully a component.
Use some ultra-targeted freeze spray on circuit caps or IC’s. There is prolly one big “chip” as the HF amp. This is not invasive when done sparingly, like don’t blast a blob of silicone grease with pressurized spray, no spray dripping, etc.
The fire is more invasive, as you are trying to get extra heat on things. A mini heat gun is good, or careful hovering of a soldering iron can get very specific. This is very dangerous so 3/8” or 7mm max proximity to anything, and collateral damage to wires etc will happen for the impatient newcomer to this method.
You are looking for the crackle to increase or decrease.
Mike
- eliminate the driver as above,
- eliminate the PSU rails as measured ON the pcb,
- inspect any interconnects, contacts on both sides
- gentle pressure with bamboo skewer or chopstick to find a partial connections,
then you can try some “fire and ice” to isolate a bad area of components, or hopefully a component.
Use some ultra-targeted freeze spray on circuit caps or IC’s. There is prolly one big “chip” as the HF amp. This is not invasive when done sparingly, like don’t blast a blob of silicone grease with pressurized spray, no spray dripping, etc.
The fire is more invasive, as you are trying to get extra heat on things. A mini heat gun is good, or careful hovering of a soldering iron can get very specific. This is very dangerous so 3/8” or 7mm max proximity to anything, and collateral damage to wires etc will happen for the impatient newcomer to this method.
You are looking for the crackle to increase or decrease.
Mike
It's been a while, but I have serviced another brand of powered monitors (Event...maybe) that had a similar issue. In that case the fault was some SMT resistors ahead of / around the amplifier chip going bad. I have seen some of these resistors fail in different ways, including going way off value, so sadly, you may want to look there.
apzx
Active member
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pvision
Well-known member
Sennheiser UK used to do menu-priced repairs on these for £220 + VAT. I checked just recently and that's no longer the case, You send them in and then they quote
I have one bad one at the moment - hissing tweeter. It's above my pay grade - I have a tech looking at it but no joy yet
I have one bad one at the moment - hissing tweeter. It's above my pay grade - I have a tech looking at it but no joy yet
That sucks, sorry to hear they’re proving less than reliable.
I wanted to like these more than I should’ve, and pulled the trigger on a few.
I outfitted a 5.1 room with 120s, and a 7.1 room with the 310s as LCR, and the rest 120s. All analogs.
Both studios have run day in, day out, never powering off speakers since 2016, minus some downtime during 2020/21.
We ran them up on the wall, high up, so left them powered on all the time.
The 5.1 room has all the first run of monitors with a more flat finish on the cabinet.
The rest are all the newer finish, which has more texture and almost a hint of sparkle.
So at some point, things changed, at least on the case finish.
I’m betting some cap subs may have happened then too.
We’ll see which fails first in our little flock.
I wanted to like these more than I should’ve, and pulled the trigger on a few.
I outfitted a 5.1 room with 120s, and a 7.1 room with the 310s as LCR, and the rest 120s. All analogs.
Both studios have run day in, day out, never powering off speakers since 2016, minus some downtime during 2020/21.
We ran them up on the wall, high up, so left them powered on all the time.
The 5.1 room has all the first run of monitors with a more flat finish on the cabinet.
The rest are all the newer finish, which has more texture and almost a hint of sparkle.
So at some point, things changed, at least on the case finish.
I’m betting some cap subs may have happened then too.
We’ll see which fails first in our little flock.
Thats interesting that they remained powered 24/7 ,
maybe powering up and down on a daily basis stresses the components more ,
Great for the pro level studio , not so good for the home studio user.
Ive a set of Behringer Truths for over 20 years , semi retired now , I kept them powered for 10 years solid , then I inherited an extra pair Id installed in a buddies appartment as party speakers after he'd found domesticity ,the wife and kid .
me and my ears are happy with much lower Spl's nowadays so I went back to passives , amp remains permanently powered though .
Simple metrics will tell you a transistor amp behaves the same either way , the ear can tell a difference though .
maybe powering up and down on a daily basis stresses the components more ,
Great for the pro level studio , not so good for the home studio user.
Ive a set of Behringer Truths for over 20 years , semi retired now , I kept them powered for 10 years solid , then I inherited an extra pair Id installed in a buddies appartment as party speakers after he'd found domesticity ,the wife and kid .
me and my ears are happy with much lower Spl's nowadays so I went back to passives , amp remains permanently powered though .
Simple metrics will tell you a transistor amp behaves the same either way , the ear can tell a difference though .
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In the case of a bad driver, you will want to get a pair, or 4, and keep your good used as a replacement for the next time. Thay way you always keep L-R balance. If you really like them, get driver sets.
The issue with all the speakers is no replacement drivers over time. No Event 2020 drivers, Westlake, Dynaudio, the list is long. All great speakers until you can't get the drivers.
Mike
The issue with all the speakers is no replacement drivers over time. No Event 2020 drivers, Westlake, Dynaudio, the list is long. All great speakers until you can't get the drivers.
Mike
amplexus
Well-known member
Same here. I've got a set of 310s. 2 years in, they're on at least 8 hours a day. No issues at all.
pvision
Well-known member
The problems on one of my KH120s started after I went on holiday & turned them off. Till then they'd been on for 5-6 years
So I'd say leave them on!
And maybe I should go on holiday more often!
So I'd say leave them on!
And maybe I should go on holiday more often!
I made a thread about repairing mine if it's any help, basically I replaced the caps with good quality ones and it's been fine since, Neumann KH120A noise issue ...ANYONE?
paulcheeba
Well-known member
- Joined
- Mar 29, 2017
- Messages
- 205
Mine just died no explanation. £240 to fix ffs.
I have posted some info about repair here
Should be possible to fix them for less than what Sennheiser UK is charging.
I think this failure is quite common, I have had three with the same story. Perhaps something in the design has been overlooked. They have an MKII version out now, I would really hope they sorted out these issues. Or maybe they didn't cause they want to keep a steady income with their £240 fixed fee repairs...
The most annoying thing is really this noise issue caused by cheap capacitors, it's totally unacceptable given the cost of the monitors and it's a shame the brands reputation has been hijacked and corrupted by this kind of business philosophy.
Should be possible to fix them for less than what Sennheiser UK is charging.
I think this failure is quite common, I have had three with the same story. Perhaps something in the design has been overlooked. They have an MKII version out now, I would really hope they sorted out these issues. Or maybe they didn't cause they want to keep a steady income with their £240 fixed fee repairs...
The most annoying thing is really this noise issue caused by cheap capacitors, it's totally unacceptable given the cost of the monitors and it's a shame the brands reputation has been hijacked and corrupted by this kind of business philosophy.
when it was klein and hummel pre neumann they definitely would not have made such compromises, I think it was one of the things the bean counters did at sennheiser owned neumann, when they bought out K+H.
That explains the "KH" prefix then...
