My Sunfire True Sub Won't Stop Humming!!! (1 Viewer)

[Chu Gai]

What happens when you disconnect the incoming cable, which I presume goes to either your TV or receiver?

 

[Seth=L]

It stops humming in these situations:
Removing the cable from the sub
Removing the cable from the receiver (the cable still connected to the sub)
Unplugging the Sub and plugging it back in with the receiver off.
The sub will begin to hum again if after the reciever is turned on and a source is fed (thus activating the auto detect) it then hums.
Seth=L

 

[Chu Gai]

I understand that Seth, what I'm suggesting you try for the moment is to leave everything connected but to remove your incoming cable or satellite from your receiver or TV. When you do that, do you still get humming?

 

[Cees Alons]

When the autodetect shuts off the sub, you're not supposed to hear any hum, of course.
But:

Removing the cable from the receiver (the cable still connected to the sub)

Does it stop humming before it turns off?
Cees

 

[Seth=L]

Cees, Yes it stops humming as soon as I disconnect it.
Chu, It doesn't stop unless it is disconnected from the receiver, if I disconnect the source (pioneer PD-65 cd player) it continues to hum.
Seth=L

 

[Cees Alons]

Seth,

If the connecting cable would only connect 1 lead (e.g. if the shielding is grounded on one side only), you would have an ENORMOUS hum, so I think that isn't the case.

You said you already "played" with the polarities of the power outlets, so that's covered too.

Here's another tip: make sure that the output signal to the sub (of your receiver) is as loud as you can set it, and diminish the volume with the dial on the sub. Not the other way around.

This way the sub will not amplify any tiny hum that's present at the outputs of the receiver.

If, however, the sub output signal on your receiver is already close to max, then perhaps it simply carries too much hum (which you might be able to check if you have a spare amplifier).

Cees

 

[Chu Gai]

There are devices called hum eliminators (busters, breakers, etc.) that sit between your amp and cable using RCA connections. What they do is break the ground and result in a drastically reduced audible hum due to the ground loop that you have in your system. They're around $10 and you can find them at places like Radio Shack, most good car audio installation centers, eBay, and professional audio places like your local Guitar Center. Try that. Often they're for stereo applications but just use one channel.

 

[Seth=L]

Thank for the advice. I am definitly going to try Cees' idea and if that doesn't work I will try the Hum eliminator.

Seth=L

 

[JediFonger]

you said that if you connect a source to the sub it hums, but otherwise it doesn't, correct? if that is the case, then it's your AVR or amp that isn't grounded. ground those and you should be able to eliminate the hum. otherwise, if it's really the sub, you should think about switching =).

 

[Seth=L]

I am just going to get rid of it. I think I like my M&K MX-100 better for music anyway.
Seth=L

 

[15hertz]

whats so good about svs subs

 

[andyman]

My sub humming very loud when just turn switch ,and no input,
please help

 

[mjbg666]

Seth -- I had the exact same problem as you did. I know this late, but I recently dug out my old MKII sub which the only difference from yours is that the non-removable plug does have a three-prong plug. But it hummed all the time, exactly like yours, and the only way it would not hum would be to disconnect the input. After my new Martin Logan sub just stopped working, I brought the MKII up from the basement. I never had the heart to throw that sub out, it really was one of the finest subs ever made (EXCEPT for that damned hum!). So, I set up the MKII, and sure enough, as soon as I connected the input back came the hum. Sooooooooooo disappointed. Well, one of the posters above mentioned using a "cheat plug". In my case, I needed the opposite kind, to turn mine from a three-prong to a two-prong. Well, guess what, the humming stopped COMPLETELY! I was literally in the process of ordering a new sub, tried this and I am ecstatic. I know this may be way too late for you, you probably long ago tossed the MK, but if you still have it tucked away somewhere, please try that plug adapter, it just may work. Mark.

 

[Mark7390]

Mine hummed and it was the nut behind the volume nob it was a little lose

 

[Mark7390]

If it still hums switch ur. Leads in side ur outlet it may be that the wires are backwards

 

[Todd Erwin]

I had this issue back when I was living in Southern California. It turned out that the line coming in to the house from my cable company that connected to the DVR was the culprit. When I routed that cable from the wall to the RG6 input on my surge protector, then from the RG6 output on the surge protector to the DVR, the hum went away.

 

[OBXBoost]

Sorry to revive an old thread, but a client brought me a Sunfire sub with a hum. There's no label on it for me to identify the model, but the amplifier board is marked "P/N 653-204-20 Rev G". Capacitor C52 is visibly damaged, as are the values. Would anyone be able to assist me with identifying the destroyed cap values?

Thanks ever so much!