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50-60Hz hum in my system


jason str

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Me too.... but
Yes it's coming out of the loudspeaker. I tested it with another outlet last night downstairs and still got the same thing. I also noticed the hum was louder with the line input plugged in.

Took some pictures but did not notice much of a deformity in the caps.
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How old is it? One circuit board I see says 2014? Filter caps should not fail after 3- 4 years. But....

Can you short the line inputs each center pin to its ground? If it still has objectionable hum with shorted inputs it is definitely the sub itself. And probably the filter caps.

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  • 2 months later...
On 8/5/2018 at 12:40 PM, sirjaymz said:

Issue Identified with Klipsch R-112SW, brand new, out of the box, 1 week ago. Stored since I bought brand new.

 

After troubleshooting for 2 days, I have successfully eliminated Klipsch hum, this looks to be due to Klipsch poor manufacturing process.

 

The LINE and the NEUTRAL are REVERSED inside the subwoofer ,on the plate amplifier , connecting your power cord to the power supply through the D-Sub connector. The connection on the D-sub is correct, The WHITE WIRE is NEUTRAL! (N), The BLACK WIRE is LINE (L).

 

However, Klipsch Manufacturing connected the NEUTRAL WHITE WIRE to the (L) input on the amplifier, and also connected the LINE BLACK WIRE to the (N) on plate amplifier. THIS IS INCORRECT. This is REVERSED.

 

I corrected this, NEUTRAL WHITE WIRE to the (N), LINE BLACK WIRE to the (L), guess what, voila, no more hum!!!

 

Use solution at your own risk.

 

IMHO, Klipsch, Fix your manufacturing in China. Do an onsite, take a look. Correct the process. Perform a recall. Get it re

 

I tried this on mine and it worked great for about 1 minute then an internal circuit breaker shut the sub down completely. If I unplug  it and let it sit for a few minutes it will repeat the process. Obviously something is overheating inside and the misconnected wires were done on purpose to hide the flaw.

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It was not the internal circuit breaker. I replaced the 6.3 amp breaker with a 10 amp fuse (the size for a r115sw, according to the pc board) and the issue persists and the fuse is not blown. So...some component in the circuitry is either faulty or incorrectly installed. More to come....I haven't given up yet. Besides, I've voided any warranty and it's just a doorstop at this point. 

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I put the wiring back as it was, white to L1 and black to N, to see if it would still work with the hum as it was before I tried the fix...no, it still cuts off after a minute or so. So I don't recommend this fix unless, like me, you simply cannot accept the hum from a sub that is sold as high end "Reference" audio gear....it most definitely is not that. I bought this junk to supplement my vintage Klipsch Heresys since they only go down to 56hz or so. My next step is to invest in some vintage Klipsch Cornwalls and update them with Bob Crites components. OLD SCHOOL RULES!!

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  • 1 month later...

Came across this thread while looking for something else.....down the rabbit hole once more  :)

 

I have a KSW-150 Sub. Am original owner and have had it for decades(?). A few years back my system developed first a hum and then a buzz problem (solved the hum before the buzz showed up).

 

I did a ground loop check (didn't expect that to be the issue becuz I had changed nothing in the system for over a year before the hum showed up). Since the sub was decades old, I considered it might be the filter caps. However, before buying and replacing the caps (may do that sometime soon anyways, just becuz) my go-to process for this kind of symptom is to first check solder joints. So I pulled out my trusty temp-controlled soldering iron and redid the filter cap connections in my best engineering fashion. Problem solved  :laugh:

 

A few years later the buzz showed up. It seemed to be related to higher levels of low freq (LF). I localized the problem to the sub (again :(  using a scope and signal gen. I first checked the sub speaker itself for physical issues. Nope. Cone movement was free and quiet (the buzz had a kind of "scritching" sound that reminded me of a voice coil going bad). Then I remembered the filter cap issue. Out comes my trusty soldering iron to redo any solder joints in the amp section that even hinted at issues (and many that didn't). Fired up the system and problem was gone (and has been for nearly 5 years.😣

 

Moral of the story....don't assume a familiar sound indicates a familiar problem. The shortest distance between two points is almost always never a straight line :)

 

In closing, for any who may need it, I have pdf copies of both the KSW-100/150/200 and SW12/15 subwoofer service manuals with schematics.  Let me know and I'm happy to email.

 

    Cheers....

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13 minutes ago, stepher said:

Moral of the story....don't assume a familiar sound indicates a familiar problem. The shortest distance between two points is almost always never a straight line :)

Cool, thanks for sharing this. The whole thread I mean but I did not want to quote the whole thing.

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3 hours ago, babadono said:

Cool, thanks for sharing this. The whole thread I mean but I did not want to quote the whole thing.

 

Always happy to help out. Many people have been kind enuf to help me over the years when I've run into (what I feel are) enigmas, so it's always nice to be able to give back to the community.  :)

 

Cheers....

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  • 4 months later...

Hello, I have an RSW-15 and two RSW-10D connected in my system for the past year or so, worked perfectly.  I disconnected the RSW-15, and when a hooked it up a few hours later there was a strong hum coming from all 3 subs. I changed and switched cables around, changed outlets, moved things around and identified the problem comes from the RCA input of the RSW-15. As soon as I plug in an RCA cable to the RCA input I get the hum from any sub connected to the system, even if only the RSW-15 is hooked up.This happens on that sub even with the pre/pro turned off. The hum goes away if I apply a little pressure to the RCA plug.  Definitely the RCA connection in the sub is causing this hum.  If I touch different thing, like amp connections, sub plate or switches, turn on or off the pre/pro, etc... the hum oscillates. That 3rd subs connection is triggering the problem, but I don't believe it IS the root of the problem.  Everything is connected as it was before the problem appeared. What could this be or how could I solve it?? Would this isolation transformer help???

 

https://www.amazon.com/Transformer-Eliminator-Blue-Jeans-Cable/dp/B00GG1PK5W

 

 

Thank you!!

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  • 8 months later...
  • 6 months later...

Years ago, I thought I’d spend a bit and get a better subwoofer cable than the Radio Shack one I was using at the time.  I bought an Ultralink cable that looked good and connected it as soon as I got home.  It seemed okay, then there was a low hum.

 

I could ignore it when the music was playing at medium volume or louder, but this hum would not go away.  Turning off the AVR would not make it stop.  Only unplugging the sub would make it stop.  At bedtime, I waited in vain for the sub to power off by itself, which it would normally do after about 7 minutes without a bass signal going to it.  In the morning, the sub was still powered on.  That was it for me.  I reconnected the old cable and the hum was gone.

 

The salesman at the shop seemed to think it impossible that an interconnect could be defective, saying he’d never heard of anything like that, but he did refund my money.  I didn’t buy anything else there for several years.

 

At least that hum was easy to solve, unlike the ones we’re reading about in this thread.

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  • 4 months later...

digging up an old thread here-  but this may help someone as well.....

I have a pair of  R-115SW's.  BOTH HUM.   one recently had an amplifier die.  the new amp also hums.  (total of 3 amps hum)   

 

I thought i tried everything - different outlets, different circuits, same circuits, different RCA cables,  isolation transformers, etc... nothing worked. 

 

Recently i was tinkering with my new umik-1  and REW, and was playing in my AVR settings.  I noticed the Sub GAIN was WAYYYYY high in the AVR. and i could never turn my sub gain knobs over  10-15% up.  I dialed the AVR gain down to zero, and then was able to get my subs up to about 40% before the hum starts. 

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First off, thanks for this thread! System as follows,

Amp: Rotel RA-1570 integrated

Mains: Epic CF-2s Crites XOs

Sub: R-110SWi Connected with RCA. Amp preouts are RCA so not using wireless

Turntable: ProJect Carbon Esprit

CD player: Kenwood

Developed an intense hum only through the mains last weekend. Disconnected all inputs and sub preouts and hum disappeared. Found it was the sub causing the hum but only in the mains. The sub was dead quiet. Scratched my head for awhile, looked for sub receipt (lol) scratched my head again for awhile. Decided while I'm back here I'd finally clean up my wires and separate everything into power and signal runs. Should have done that from the get go but we all know when you get a new system the fastest way to get it up and running is usually not the best way. So cables are separated now and nowhere near each other anymore. Still hums through mains when sub is connected but it sure looks better. At the end of my rope so just for gits and shiggles I went and grabbed an old Monster RCA cable from the parts closet and swapped it with the KnuKoncepts Triple shielded dedicated subwoofer cable (lol) that has been in the system since new. Dead freakin quiet. So my question is, how does an RCA cable develop a hum after a couple of years of use? Scratching my head yet again only now to crystal clear audio.

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26 minutes ago, Harleywood said:

So my question is, how does an RCA cable develop a hum after a couple of years of use? Scratching my head yet again only now to crystal clear audio.

Sure the ground contact of the RCA connectors are nice and tight? And clean?

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