Logitech Z-5500 subwoofer hum

Hi, I am a new Z-5500 user, and I have noticed some subwoffer humming.

I experience a low buzz/hum coming from the sub when the system is on (blue console led). It's clearly audible when no music is playing. It is still there when nothing is hooked up to the console, even in MUTE mode. I have examined it a bit and I am pretty sure this sound is made by the speaker itself (it's best heard from the subwoffer's front side). The does not get louder or softer with changes in the volume setting and there is no hiss from the satellites.

I have tried turning off the system, unplugging the console cable and re-plugging it in firmly but that doesn't seem to help.

The hum goes away when the unit is turned off via either the control pod or the switch on the back of the sub. In standby mode when I get closer with my ear to the sub I hear a bit if buzzing, from the inside, though it's much less noticeable than the buzzing when the system is on.

I have already tried changing the polarity, with no effect.

If there are any z-5500 users, please let me know, if you also suffer from this issue?

I'm also having this problem. I think the slight buzzing from the inside of the sub is the power transformer, but as for the humming, I have no idea . I am using an SB Extigy, which if connected using the 6-ch direct inputs, creates this awful hum. My DVD player does the same if connected to the digital coax input. The humming stops if I disconnect all electrical inputs, and just use the optical input. I don't think it's a problem with the speakers as I tried connecting my minidisc through one of the analog stereo inputs and it sounded great, no humming . I only experience the problem when connecting mains-powered devices to the speakers.

Yes, I tried moving the cable around last night and now the buzzing has stopped! If I just move the cable slightly, there's a thump from the sub. Do you know if this is a cable problem or just a bad connection with the socket? I really don't want a busted cable on my new speakers!

I've sent an e-mail to Logitech, I'll let you know what they say.

I've had a reply from Logitech although it doesn't help very much. They say it is an isolated case (although I told them a number of people are experiencing the problem). They said the connection may be lost under the strain of moving the cable, but it won't get any worse.
Having had another look at my system, I think it is just a bad connection with the socket. I kept the cable still and just moved the plug very slightly and got the thumps. I then held the plug and moved the cable but didn't hear any thumps. It may be a loose pin or something. This may be the case with yours.

This message was edited by pjcook on Feb 16 2005.

Well, I figured out already it was a problem with the contact between the control pod cable and the sub. I tightened the screws a bit more and now the humming is gone. Just an occasional blob-sound from the sub, but i think i can live with it.

Oh, and it definitely isn't an isolated case as logitech says.

Had the same problem, decided to move the connection around to no effect, then removed the console connector from the sub (without switching the power off).... no more hum, no more power up - no more work!

Will try to replace the fuse tomorrow.

Replaced the fuse, and we're up and running again.... phew!

Tightened the connection to the subwoofer.... and the hum reduced significantly, but was still audible. Decided to move the cable (attached to the connector, attached to the subwoofer) around, and bingo! Found a sweet spot where the hum ceased to exist. Taped the cable in place just to be certain!

FANTASTIC!!

The Logitech Z-5500 is connected to the digital tv set top box and produces outstanding quality sound.