50-60Hz hum in my system

[Harleywood]

2 hours ago, billybob said:

Going to mark it down to just one of those things.

Remember when you got your Rotel abit ago.

Is it powerful enough for your Epics? 

Thanks!

@Harleywood

Plenty of power. Ran them on a 80s Kenwood amp/pre and didn’t need the sub until the Rotel. Kind of a strange scenario with the CF2s and the Rotel. It’s not that the Rotel doesn’t provide enough bass through the tone controls it’s that the CF2s horns are so bright that I have to run treble control at zero to negative one. The Rotel might also be a tad bright which doesn’t help. Relative to that the bass control now has to go down to negative four to six or else it sounds exactly like what your thinking it would. Dark and muddy. Added the sub and dialed it in and couldn’t be more pleased with soundstage. 

[Harleywood]

2 hours ago, babadono said:

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

I did check the cables. They look good. I noticed the the metal ferrules are a bit large so I plugged them in again and they do touch ever so lightly. Don’t notice when you look or feel but I couldn’t shove a piece of paper between them. 

[billybob]

6 minutes ago, Harleywood said:

Plenty of power. Ran them on a 80s Kenwood amp/pre and didn’t need the sub until the Rotel. Kind of a strange scenario with the CF2s and the Rotel. It’s not that the Rotel doesn’t provide enough bass through the tone controls it’s that the CF2s horns are so bright that I have to run treble control at zero to negative one. The Rotel might also be a tad bright which doesn’t help. Relative to that the bass control now has to go down to negative four to six or else it sounds exactly like what your thinking it would. Dark and muddy. Added the sub and dialed it in and couldn’t be more pleased with soundstage.O have

Very glad to hear that. Recall you were looking for integrated with sub out. Took the time reading an old Digital Trends review. Take it that you are happy now...cool if that is the case. Throwing only 50 wpc at my still new to me CF-1s.

Nice but know I need more.

Thanks for letting me know...

[Paco Elzaurdia]

El 18/2/2019 a las 14:05, stepher dijo:

Encontré este hilo mientras buscaba algo más ... por la madriguera del conejo una vez más 

 

Tengo un KSW-150 Sub. Soy el propietario original y lo he tenido durante décadas (?). Hace unos años, mi sistema desarrolló primero un zumbido y luego un problema de zumbido (resolvió el zumbido antes de que apareciera el zumbido).

 

Hice una verificación de bucle de tierra (no esperaba que ese fuera el problema porque no había cambiado en el sistema durante más de un año antes de que apareciera el zumbido). Dado que el submarino tenía décadas de antigüedad, consideré que podrían ser las tapas de los filtros. Sin embargo, antes de comprar y reemplazar las tapas (puede hacerlo pronto de todos modos, solo porque) mi proceso de referencia para este tipo de síntoma es verificar primero las juntas de soldadura. Así que saqué mi confiable soldador de temperatura controlada y rehice las conexiones de la tapa del filtro con mi mejor estilo de ingeniería. Problema resuelto 

 

Unos años más tarde apareció el rumor. Parecía estar relacionado con niveles más altos de baja frecuencia (LF). Localicé el problema en el sub (nuevamente   using un alcance y un generador de señal. Primero verifiqué el altavoz secundario en sí mismo para ver si tenía problemas físicos. Nop. El movimiento del cono era libre y silencioso (el zumbido tenía una especie de sonido De "deslizamiento" que me recordó a una bobina de voz que va mal). Entonces recordé el problema de la tapa del filtro. Aparece mi confiable soldador para rehacer cualquier unión de soldadura en la sección del amplificador que incluso insinuó problemas (y muchos que Encendió el sistema y el problema desapareció (y lo ha estado durante casi 5 años.😣

 

Moraleja de la historia ... no asuma que un sonido familiar indica un problema familiar. La distancia más corta entre dos puntos casi nunca es una línea recta.

 

Para terminar, para cualquiera que lo necesite, tengo copias en pdf de los manuales de servicio del subwoofer KSW-100/150/200 y SW12 / 15 con esquemas. Avísame y estaré feliz de enviarte un correo electrónico.

 

    Salud ....

Me interesa la copia en pdf del diagrama, tengo el mismo problema pacoelz@adinet.com.uy

[OliGil]

Hi all.  I am looking for a PDF copy of the KSW-200 subwoofer service manual with schematics.  Does any of you have it?  Thank you.

 

On 2/18/2019 at 6:05 PM, stepher said:

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 

 

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....

 

[Roger T]

On 11/3/2016 at 4:10 PM, jason str said:

Have a 50-60Hz hum/buzz in your system ? Its likely a ground loop issue and luckily there are ways to combat the issue.

 

Feel free to make this a sticky as the issue is common and not just related to subwoofers.

My Klipsch SPL120 subwoofer generates hum too!  I bought an isolation transformer. It didn’t remove the hum.

[Roger T]

On 11/27/2021 at 9:48 AM, OliGil said:

Hi all.  I am looking for a PDF copy of the KSW-200 subwoofer service manual with schematics.  Does any of you have it?  Thank you.

 

 

Do you have the schematics for Klipsch SPL120 subwoofer?

[billybob]

23 minutes ago, Roger T said:

My Klipsch SPL120 subwoofer generates hum too!  I bought an isolation transformer. It didn’t remove the hum.

Did you try a 3 prong to 2 way groundless adapter to troubleshoot yet?

Thanks!

[liquidsquid793]

Going to jump into this messy issue. There are few ways of getting AC line hum in your audio system:
1. Ground loops.

2. Current induced in cabling (transformer effect) by nearby large current AC loads like motors/compressors, ovens, heaters, etc.

3. Voltage induced in cabling from nearby noisy sources such as florescent bulbs, transmitters, and generally poorly designed electronics.

4. Power supply in a piece of equipment is failing and has abnormal AC ripple.

5. Noisy AC.

 

1. Ground Loops:

These can be stinkers to deal with. Commonly caused by having your system plugged into multiple wall outlets around the room. It is quite possible they are sourced from two different circuit breakers and thus the grounds between the two are not tied directly together or the grounds are poor, allowing them to be different in voltage potential at each outlet. A few milivolts is all it takes. This in turn winds up making the cabling of your audio become part of the ground return which gets AC noise in everything. (Just ask anyone who tries to get hum figured out on large music installations)

Grounds need a single point of connection, and the circuit breaker box isn't really it. It actually is the point on your house where the ground rod is outside where the AC enters the home. This allows ground differentials around the inside of the electrical box and throughout the home.

To test the theory, try using a multiple outlet heavy duty extension cord and plug all the equipment into it and a single outlet and see if the problem persists or not. If it goes away, ground loop is your issue.

To fix if you are forced to use multiple outlets requires a bit of effort. Simply tying the equipment grounds together may not be enough as it only reduces the loop current, not eliminate it. The fix may involve an electrician as the grounds should be solidly tied together at the wall outlet, not on the equipment. Have the electrician get all your AV equipment on a single breaker, refresh the grounds and/or decrease the gauge (increase the diameter of the ground wire). Another method would be to bond the offending grounds together inside of the electrical box before returning to the ground bar of the box, but this runs risk and only an electrician should dink around in those things doing something outside of code.
Helpers can be to put equipment on other outlets like subs on wireless which "breaks the loop". Sometimes using XLR connectors for your audio can address the problem in those cables but does not get rid of loop current issue, it just prevents it from getting in that cable's audio. It is still running through the shield if the cable has a shield connected on either end. In many cases, the hum still gets into your electronics through the enclosure or other connections. 

Shielded cabling should have little effect on this problem, nor expensive wire. Improving house wiring will have the most bang for the buck and is the right solution.
Note that lifting/disconnecting the ground from the offending outlet or equipment may fix the hum, it opens your equipment for a whole Pandora's box of other issues. Electrostatic discharge damage is just one of them (a zap from your finger has nowhere to go but to sensitive electronics). Nearby lightning strikes with similar effect as they induce large collapsing electrical fields. No ground, no protection. That is why there is a ground pin. In other cases, there will be noise filtering to ground on both the power supply and speaker outlets. You just defeated all of that by disconnecting the ground.

 

2. Current induction. Only decent solution is XLR cables for the audio path or moving things away from each other. It can result in creating effects much like a ground loop and is sometimes complicated by long unshielded wires like speaker cables but typically not as the out and back of parallel wires rejects this.

 

3. Voltage induction. XLR cables and/or higher quality RCAs. Sometimes you take a look at the guts of cheap cables, and find they are aluminum foil wrap with a strand or two of thin gauge wire. Fine for electrical shielding as long as the crimps are the jacks are actually connecting. You cannot solder to aluminum with standard solder, so crimps are used, and those easily fail. Aluminum also gets oxides making it get worse over time. Get decent cables! 

 

In the case of strong interferers like nearby cell towers and transmitters (even your cell phone) you may need shielded cable on everything including your speaker wire. You may get away with putting EMI filters on your speaker wires at the amplifier for less money. This is an uncommon issue but can manifest like hum as the RF noise energy gets into circuits it shouldn't and cases all sorts of weird issues.

 

4. Needs no explanation, track down the offender and get it fixed.

 

5. Noisy AC is caused by other loads on your electrical system creating noise on your electrical system power. Old-school lamp dimmers were notorious for this. Replace them, they are cheap! Track the load down causing the problem and fix it. If you cannot, a power conditioner may be your only option. Rarely wire is installed in a home with inadequate gauge for the load on it, and this can be a symptom. This is a huge and expensive problem to fix. Sorry.