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Almi's Logitech Z-5500 Mod (High-End upgrade for the speaker system) - Page 2

post #16 of 400

Hi guys. I´m trying to fix my sub by changing the 10000 uF capacitors, but cannot separate the pcb from the heat sink (i cant see the way).


Any help appreciated.



post #17 of 400
Thread Starter 

Simple. Looking from the back of the sub, first you need to remove all the screws holding the right heat sink. The next is inside, the 10 long screws on the longer sides of the PCB (holding the TDA amps to the heat sink). And finally, one screw holding each side on the shorter ends (on the top of the panel). Than you can move, and remove the right heat sink completely and lift up the PCB one side. Done.

Edited by ramachandra - 9/26/13 at 7:53am
post #18 of 400

hello! i'm looking for solution on my z5500's hissing sound and stumbled upon this very interesting topic about z5500. and i can't help it but to be a member of this forum so that i can post to this forum. btw, please pardon me if my english is bad. i'm not an american nor brit.


anyway,as what i've said, i'm looking for solution on my z5500. i have gone through two appliance repairmen nearby our area and they told me that the IC connecting the pcb and the heatsink causes the hiss and needed to be replaced (all of it). but what i have read on the internet, any of it's large capacitors may be loose and must be soldered once again. i told them what i read on the internet but still they insist that it's not the problem. one of the technician said that caps don't easily become loose nor busted. some technicians here in our country are not telling the truth. instead they are telling the customers that their units have big problem so that they can charge for a higher cost and i don't want to be fooled by their tactics. so if i may ask, can you tell me what seems to be the problem with my unit?


and since the topic is about upgrading z5500, is it possible to change and add a second sub? i read that z5500 has 8 ohms sub, can i install 2 bridged 4 ohms sub and what sub wattage should i consider? and also, can a z5500 be modified to be powered in 12vdc so that it can be installed in a car?


please enlighten me. again, sorry if you may find wrong grammar on my post. thanks in advance!

post #19 of 400
Thread Starter 

Hi, Where is the source of the noise you hear exactly, and when? Unfortunately many things can cause a problem you have, even positions of the cables.


I know one guy who complained about a constant noise from the Sub when the system is turned off just on the control pod. He checked the two main 10000uF filter capacitors and one of them had the top cracked up. It means for the cap the game is over. On other forums i found the Su'scon caps have a tendency to fail without external signs, so no way to be sure anything without proper equipment, or replacement.


I have to agree with the repairmens in general about the the strength of the soldering. In most situations the the legs of the components rather break out from the body instead pulling out from the PCB, but it is not true about the Z5500. I bought 12 Amplifier board for repair and upgrade recently, and thanks to the poor packaging many of the big caps completely break off form the boards in one piece during transportation. Just for fun i have done the same with few others to see, and happened so easy. Cheap stuff......


The Sub have two TDA amps, if one of them failing it make sense the repair men want to change them both, but the other channels have one each, so to change all 7pcs is clearly not necessary. Providing schematics with products for repair purpose went out of fashion in the age of throw away customers. I can imagine easier to replace all the TDA Amps instead wasting time with reverse engineering and get the clear picture how it works and pick the wrong one.


You can find many videos on YouTube what other people used, to replace the speaker of the Sub. The original is: 188 watts RMS 8 ohms 100Hz 10% THD. Using it in the car is technically possible with a 220V inverter, still i doubt it is wise because not designed to use up the available power on the most effective way, like a car amplifier. A simple modification to make it run from 12V is unlikely.

Edited by ramachandra - 10/31/13 at 1:29pm
post #20 of 400

thanks for the reply! 


about the hissing/humming sound, it only comes when i select analog. if i connect a digital cable (optical/coax) and select digital input on the z5500, it's also present. no digital connection present, no hiss.


they opened my z5500 yesterday for checkup on what might be causing the problem. while they are doing this free diagnostic check, i also checked the 3 caps (2 large and 1 medium) by placing my fore-finger on top of each of the caps and gently shaking it if it is loose. the larger ones aren't loose as what i felt. the black (medium sized) is a bit shaking. but the technician said that it is not the culprit, . he said that a capacitor can be a bit shaking but it's still working fine, instead he insisted that the ic connecting the heatsink and the board causes it. i think he just want to charge me for higher cost that's why he's telling me that since if he solders the loose cap, it won't be that costly.


can i troubleshoot that myself? i mean, can i power on the z5500 and hold the black cap firmly for a better contact with the board so that i would know if it's the real culprit? wouldn't i be electrically shocked holding that while powered on?


edit: z5500 already repaired. i insisted them to re-solder the large caps first but if the humming still persist, then that's the time that they will do what they think the problem was. they couldn't believe that my unit was now ok by just soldering it once again.


btw, i'm planning to hack a bluetooth headset/receiver or fm receiver and tap it on one of z5500's stereo input and hide the headset components inside the control pod. is there an available 5v source on z5500's control pod to supply the bluetooth receiver and a 5v fan?

Edited by paranoiarebirth - 10/31/13 at 6:11am
post #21 of 400
Thread Starter 

That was a smart move to pushing those guys to do the re-soldering first. :D


Now i have done some experiment on the pins of one big cap, to see why they are get loose easy, and as i see the solder is not stick to them properly, because the quality of the metal used to cover the pins.

The 2 biggest caps are stuck to the panels with a strong glue, but as i see the plastic covering the metal body is not always strong enough to withstand the vibrations and spit, then it is depend on time when the trouble starting.The third is almost the same just some of them got not enough glue to last (belong to the control pod).


The pod get +18 -18 and +8V from the Sub, and the panel inside have few voltage regulators, and possibly have 5V available for the chips. There is a real chance the fan generate unwanted noises and as i saw in amplifiers it has a separated power source from the analog circuits. From the point of sound quality and stable operation i recommend external power source, like USB (+5V) and you can install a connector for the USB to the back of the plastic housing, and the lead can run parallel with the analog cable from the PC.

post #22 of 400

hello once again sir ramachandra! i think my z5500's main caps starts to get loose again. there are times when a boom in bass generates an unwanted noise. as i recall, the previous also started with this one. and so i'm planning to upgrade my system but only one at a time. i'll start with the 2 main caps. can you tell me what are all of these? http://cdn.head-fi.org/5/5a/5a5115e2_PSUcapacitors.jpeg


by the way, is upgrading one at a time possible or i must upgrade all if i change one component of it?




edit: what are these blue square ic? http://cdn.head-fi.org/f/f0/f0d17c24_LogitechZ5500aplifierpanelbottomviewafterthemodding.jpeg

Edited by paranoiarebirth - 11/22/13 at 5:06pm
post #23 of 400
Thread Starter 

The first link is the main filter capacitor and i do not think you should spend your money and effort to build a similar. I have made it for a system, what is already had better speakers and a modified soundcard, and i just attempted to push out the max from it. If you wish to upgrade your Z's main filter capacitor with the smallest hassle as possible use Nichicon FW or Nichicon KW (better), than the sound becoming a bit softer, more musical. With Elna for Audio it is going even further, + the bass will improve, and the sound is more involving. Unfortunately will not fit directly to the panel.

On the second link the blue boxes are capacitors, some of them on the signal path, some of them on the bootstrap. The advantage using capacitors parallel is simple, the  smaller caps are react faster to voltage changes than bigger, and able to filter out noises more effectively, or let high frequency sound pass easier on the signal path. Only can do a little difference for the system so i suggest to leave it to the end when you have nothing better to do, or leave it all. It is completely your choice how you upgrade the system, no need to do everything in the first time. I currently have few upgraded board and I'm looking for broken boards to buy in return.

post #24 of 400

Sir are thees parts you list the best i can buy and are they the most functional i can buy to date,for your mod ?.

I am very impressed by your knowledge of this system.I have 4 of them and would like to upgrade all of them.


 Thank You             flatop.  

post #25 of 400
Thread Starter 

The Elna Silmic II is the best you can get from audio grade electrolytic capacitors from the sound point, and compared what they do and what they cost it is cheap. The easy source is eBay and Mouser in my location. Replacing OpAmps i suggest to use 5pcs 0.47uF K73-16 Soviet military film capacitors. Perfect for other areas as well if the size is fit.


For the Sub still the Opa1602AID is my winner under the circumstances, because using Opa2228P result a deeper nicer bass, but no space between the wires and other components. Plus require an adapter and the chance is there to becoming loose if not stabilized.


The Elna for Audio (or Denon) as a main 10000uF filter capacitor provide a really cool bass, I was not entirely happy with Nichicon KG, KW according to my taste.

post #26 of 400

After looking a little on the internet regarding my problem, i decided to post here:

I recently bought a second-hand Logitech Z5500, it sound quite well, the only problem is that it doesn't sound as loud as it should be, for its power i think it should be louder.

Maybe you have an idea?



post #27 of 400
Thread Starter 

Checking the driver or settings of your sound card worth a try first, than compare the loudness to other Z5500 or Logitech speaker system if you can. I have many ideas, but the system is complex enough so i do not see the point to start a list and cause confusion, specially if nothing wrong.

Edited by ramachandra - 5/9/14 at 4:46am
post #28 of 400

Hello. I will check the driver, the sound card is integrated Realtek, but i don't think that should a problem, or is it?

post #29 of 400

I reinstalled the drivers and the problem persists. Any ideas?


post #30 of 400
Thread Starter 

Integrated Realtek Sound Card is A problem, not The problem ;-) Try to hook up the system to a different computer or use the digital connection. Even an iPod do for testing.

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