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morphine
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Re: z-5500 hum hiss - updated :(

Fri Mar 05, 2010 2:55 pm

Just in case you haven't noticed, the OP now has a new problem and the unit is now actually nonfunctional.
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Re: z-5500 hum hiss - updated :(

Fri Mar 05, 2010 3:32 pm

morphine wrote:
Just in case you haven't noticed, the OP now has a new problem and the unit is now actually nonfunctional.


Missed that ... :oops:
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Digita1 Ecstasy
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Re: z-5500 hum hiss - updated :(

Mon Jun 07, 2010 3:42 pm

Sorry to bring a dead thread back to life but, google searches are getting me nowhere.


I've had close to identical issues that OP had and have tried every possible solution brought up in the thread. I bought my z 5500's used, hooked up optically to my ps3, and coax to my pc. First time around there was very little humming, almost a whisper. If I used 6ch direct there was none. After moving the position of the sub further away from my tv, and to better the position of the surround sound the humming went from a whisper to having an unacceptably loud presence. It is unbearable to listen to these speakers at low volume now.


I tried unplugging and plugging everything back in. Logitech said florescent lightbulbs or dimmer switches in a room can cause interference (both of which my room has). Took them to another room, plugged directly into a wall. No gain. I eventually began to think it was the control pod to sub cable that was **** up. Wiggling it around, playing with the pin connector to the sub, or even fumbling the control pod upside down would decrease/increase the hum. Now doing any of that does nothing.


Also with my system hooked up properly, say when I am playing PS3 with optical input, the control pod will read that it detects nothing, only when live sound is present. (ie noise in a game, clicking around the XMB menu) During silence like load screens the hum will die, along with the audio signal and the control pod will go back to saying there's no input detected. These symptoms are identical when hooked up to my external sound card for my pc. Clues, anyone? Desperate here.

Edit: It's Firmware 2.0.4 - Control Pod PID is R608
Last edited by Digita1 Ecstasy on Mon Jun 07, 2010 3:58 pm, edited 1 time in total.
 
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Re: z-5500 hum hiss - updated :(

Mon Jun 07, 2010 3:56 pm

Welcome to TR!

My apologies if I'm asking the obvious, but are those still in warranty? I'd simply take them back instead of wasting more time with them.
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Re: z-5500 hum hiss - updated :(

Mon Jun 07, 2010 4:05 pm

I tried unplugging and plugging everything back in. Logitech said florescent lightbulbs or dimmer switches in a room can cause interference (both of which my room has). Took them to another room, plugged directly into a wall. No gain. I eventually began to think it was the control pod to sub cable that was **** up. Wiggling it around, playing with the pin connector to the sub, or even fumbling the control pod upside down would decrease/increase the hum. Now doing any of that does nothing.

Also with my system hooked up properly, say when I am playing PS3 with optical input, the control pod will read that it detects nothing, only when live sound is present. (ie noise in a game, clicking around the XMB menu) During silence like load screens the hum will die, along with the audio signal and the control pod will go back to saying there's no input detected. These symptoms are identical when hooked up to my external sound card for my pc. Clues, anyone? Desperate here.


My guess would be that a connection inside the unit is physically cracked at this point. The fact that you could change the hum by moving the unit around suggests that something was wiggling; and they fact that you can't do it anymore suggests that whatever that something was isn't wiggling anymore - it's either lodged or cracked in such a way that the wiggling no longer affects output.

Add to this the fact that it sees "no input" whenever there isn't actually sound playing at your source - and with different sources - suggests a bad connection within the unit itself.

You could try opening it up and looking for anything that looks loose or cracked. Before doing that, rule out bad cables etc.
 
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Re: z-5500 hum hiss - updated :(

Tue Jun 08, 2010 1:32 pm

Thanks for a fast reply, and honestly. . . If I could return the speakers and get new ones I would. But I am a poor audiophile.


I'm pretty sure the problem lies within the control pod, or the VGA type connector to the sub. Maybe the cable too. How would I go about checking for a faulty cable? I opened up my control pod and took pictures. Everything seemed OK~ but I have an untrained eye. Everything seemed snug and in its place.


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Re: z-5500 hum hiss - updated :(

Sat Nov 11, 2017 3:12 pm

I am sending out this warning message to everyone owning a z5500 or z906 or any sound system from Logitech.
My system is about 5 years old, very good condition, bought second-hand two months ago. A couple days ago it started making an annoying hiss from the speakers. The humming sub was that way from the begging.
Anyway, I decided to open the sub and see what could be wrong. I was astonished when I saw that one of the wires, specifically the red one coming from the toroidal transformer, was missing from the bridge rectifier and was glued with silicone to the floor of the sub.There were just the other three wires connected to the bridge :two yellows and one black. So the system was working with a mono-phased bridge rectifier and the DC voltage it was providing to the main board was not as constant as with the full bridge working. You heard me right, the red wire had its connector GLUED with silicone to the base of the sub. The bridge rectifier is supposed to work using 4 diodes, but with the red wire disconnected, two of them were not used, for smoothing out the AC voltage. Now I am really mad at this company and specifically at the worker who could not get his **** together and connect all the wires properly,making such a big **** mistake. Anyone who is experiencing hissing in speakers and humming from the sub should CHECK THE BRIDGE RECTIFIER!!!
 
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Re: z-5500 hum hiss - updated :(

Sat Nov 11, 2017 4:09 pm

It was obviously working fine without the other phase until a couple of days ago. I think something else has failed.

Maybe post a pic?
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Re: z-5500 hum hiss - updated :(

Sat Nov 11, 2017 8:28 pm

Seven year necro? Is that a new record? My Z-680s have got to be 10+ years old now. The one rear sat has mouse holes chewed in the diaphragm and the backlight on the volume/controller pod is almost completely dead. Still sound pretty great though.
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Re: z-5500 hum hiss - updated :(

Sat Nov 11, 2017 10:32 pm

SergiuDan wrote:
I am sending out this warning message to everyone owning a z5500 or z906 or any sound system from Logitech.
My system is about 5 years old, very good condition, bought second-hand two months ago. A couple days ago it started making an annoying hiss from the speakers. The humming sub was that way from the begging.
Anyway, I decided to open the sub and see what could be wrong. I was astonished when I saw that one of the wires, specifically the red one coming from the toroidal transformer, was missing from the bridge rectifier and was glued with silicone to the floor of the sub.There were just the other three wires connected to the bridge :two yellows and one black. So the system was working with a mono-phased bridge rectifier and the DC voltage it was providing to the main board was not as constant as with the full bridge working. You heard me right, the red wire had its connector GLUED with silicone to the base of the sub. The bridge rectifier is supposed to work using 4 diodes, but with the red wire disconnected, two of them were not used, for smoothing out the AC voltage. Now I am really mad at this company and specifically at the worker who could not get his **** together and connect all the wires properly,making such a big **** mistake. Anyone who is experiencing hissing in speakers and humming from the sub should CHECK THE BRIDGE RECTIFIER!!!


The fact the wire was glued to the floor probably means it was designed like that.
If I remember correctly half wave gives 0.7 DC of AC voltage.
and full wave gives 1.4 X of AC voltage..............

Make sure all your connections are firm.
Check you'r not running any low-level audio cables parallel to power cables.
good luck.
 
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Re: z-5500 hum hiss - updated :(

Sun Nov 12, 2017 4:54 am

SergiuDan wrote:
I was astonished when I saw that one of the wires, specifically the red one coming from the toroidal transformer, was missing from the bridge rectifier and was glued with silicone to the floor of the sub.There were just the other three wires connected to the bridge :two yellows and one black. So the system was working with a mono-phased bridge rectifier and the DC voltage it was providing to the main board was not as constant as with the full bridge working.

Your astonishment may have diminished after studying the circuit more closely. This doesn't sound like a manufacturing botch-up, it sounds like a cheap-and-cheerful way of differentiating between 120 and 240V models without having to to modify any other components save the power cord. As long as the rectified DC is feeding into a switch mode power supply the extra ripple current doesn't matter much.
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Re: z-5500 hum hiss - updated :(

Sun Nov 12, 2017 11:09 pm

ludi wrote:
Your astonishment may have diminished after studying the circuit more closely. This doesn't sound like a manufacturing botch-up, it sounds like a cheap-and-cheerful way of differentiating between 120 and 240V models without having to to modify any other components save the power cord. As long as the rectified DC is feeding into a switch mode power supply the extra ripple current doesn't matter much.


Your probably spot on there.
I might be a little out of date,but all that's required is a basic linear PSU-transformer-rectifier-smoothing capacitors.
with the size and quality of the capacitors the most important.
probably a chip amp that'll run on anything from 9 to 30 volts.
Most power amps run off a plus and minus supply-last I built for a 60 watt mosfet amp was 40-0-40....................
 
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Re: z-5500 hum hiss - updated :(

Fri Feb 16, 2018 3:22 pm

I want to give you an update.After I discovered that the red wire was glued to the floor of the sub,I checked to see what was the AC voltage I got from that wire and it was around 50V.So I connected that wire on the bridge rectifier.The thing is that now I rarely get that intermittent hiss and when I do,the duration is greatly reduced.Anyway the hiss might have something to do with interference from some heaters or some signals,coming from out of my flat,rather than the wire not being connected. But I want to mention that the way this bridge rectifier is connected,in identical Logitech Z5500 systems I found on the internet,is with all the wires (2 x black,1 x yellow,1 x red),going from the transformer,to the bridge,cause otherwise it just doesn't make any sense. So this red wire that I found glued to the sub,was definitely not a design feature but rather,a cock-up from one of the employees who assembled the system.It is a known fact that,electronics connected to a smoother voltage signal will last longer than those connected to a half rectified voltage signal.I really wonder if this thing was not actually a deliberate,act from the manufacturer,of making this system brake sooner than later.This is a page of the head-fi forum in which you can see a image that shows a Z5500 opened sub with the bridge fully connected https://www.head-fi.org/threads/almis-l ... 15/page-23
 
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Re: z-5500 hum hiss - updated :(

Fri Feb 16, 2018 3:44 pm

I got a first generation set of Z-5500s (had RCAs connectors instead of the more standard pin/spade connectors found in later Z-5500s) that are almost thirteen years old that mostly work. A few years ago the RCA cable for the left rear speaker got frayed in an accident and that channel barely works. I suppose I could attempt to repair the cable but I'm just too lazy.
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Re: z-5500 hum hiss - updated :(

Fri Feb 16, 2018 5:23 pm

You should repair it, you can blow out an amp like that IME.
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Re: z-5500 hum hiss

Fri Feb 16, 2018 7:12 pm

SpotTheCat wrote:
Here is a video of the weirdness. Optical no longer freezes it, but analog does.
http://www.youtube.com/watch?v=v7S3vwHsC5c


Wow....
Trust Logitech to put cheap Chinese electronics where they have no place being.
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Re: z-5500 hum hiss - updated :(

Fri Feb 16, 2018 10:27 pm

morphine wrote:
You should repair it, you can blow out an amp like that IME.


I managed to cut off the bad section and spice the stock cabling but ordinary electrical tape is only so good at combating impedance and cross-talk. There's noticeable static in the output on that channel but it is much better than before but not perfect. Can't really complain though for a nearly 13 year old set.

I'll probably upgrade to a real 5.1 digital receiver setup since DD/DTS passthrough via Displayport/HDMI is the way to go with 3D audio on modern gaming titles.
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Re: z-5500 hum hiss - updated :(

Fri Feb 16, 2018 10:46 pm

Krogoth wrote:
I'll probably upgrade to a real 5.1 digital receiver setup since DD/DTS passthrough via Displayport/HDMI is the way to go with 3D audio on modern gaming titles.

You don't need DD or DTS. Standard HDMI passthrough can do 5.1 (7.1?) PCM, so all you have to do is connect the cable and magic.gif.
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