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

[jayjayuk]

@ramachandra i have also been looking at the kw series aswell... but they are hard to find on ebay (for me anyway) at 10000uf 50v same for the 4700uf 25v... maybe i need to search more
that control pod looks cool... very simple and effective design... my would be something like that but on the back of the plate... so then you just have to use rca's or jacks (have not decided yet... maybe both go in)... i like options... its just the only thing i can thing of using from isolationg one lot of wires from one point to another is relays or optos... i just dont know if the optos will add resistance to the wires and if it will have an adverse affect on the sound in the end... i will have to look some stuff up and some datasheets and see what i can find.
i might wait i might not hehe... depends how impatient i get because i want to try them... i did some measurements last night and i would have to move the resistors to the underside of the board and possibly the wires that connect the pre-amp to the main board... it would be a mod that i would do but only if i thought they made an improvement would i keep it this way... something i need to ask you... 3 things actually... i noticed in one of your mods you used polystyrene they maybe look like siemens 220nf... can i ask where did you source these from and how much? as these 220nf styroflex are quite hard to find... all the lower values are cheap but i cant use them anywhere in this project. also if i did buy those russian styroflex the case is metal and i have to run one of the leads down its side to connect to the board... will there be a problem if one of the leads touches the case of the capacitor? should i insulate down one side of the cap as i run the lead down it? these caps are very tall so staggering them from on side of the pcb to the other is not an option as there is not enough space on the back side of pre-amp board.... oh well.
i have noticed that the 220nf 630v axial i have used on the underside of the board (which is now on the top side going through) it creates a hum on the sub... if i move my finger closer to the plastic casing the hum gets worse until a peak when i touch the plastic... then if i touch the lead of that cap (or any 630v cap) or the plate the hum goes away? have any idea what i can do to sort this?
 
@andro6600 they are quite big which is making me look for others first before i actually purchase these ones.. if i can not get any others then i will mod these in... i know i can get them in re-arranging stuff just it wont look nice... but i will do it yes please let me know what you think about the sound with the polypropylenes as i might buy some of these aswell as they can go in either board i have while the others go in the other board i have... i am just not sure about the lead of the cap touching the cap case.
 
 
Something arrived today the 5 X opa1612 i dont know if i should get them in now or wait for my elna's to arrive and do it all at once... decisions decisions... i know i wont be able to wait haha...
i will most probably be buying more of these in the end... if any of you two know where i can get these cheaper than where i have bought them from i would be very interested in saving some money
 
heres the ones i bought...
http://www.ebay.co.uk/itm/Burr-Brown-OPA1612-Soundplus-high-performance-bi-polar-op-amp-soic-8-pin-package-/251501882803?pt=LH_DefaultDomain_0&hash=item3a8eae2db3
 
here they are on my kitchen side

 
Cheers
 
EDIT : 
 
as polystyrenes are hard to find @ 220nf and a low voltage to fit in the pre-amp board... would there be any adverse effects if i used say a 240nf or a 270nf instead of a 220nf?
 
Cheers

 

[andro6600]

I am wondering the same about metal case of these caps. @ramachandra, maybe you can enlighten us is that a problem, or we need some insulation over the body? Is it ok with just insulation tape?
 
@jayjayuk congrats for the opamps! They are really superb, and made most of the difference. Be careful with the soldering iron, because i screw one of mine. And with desoldering old ones too.

 

[jayjayuk]

yes @ramachandra we need info about the metal caps casing and your experience with them and best practice of installation... thanks.
 
@andro6600 i was thinking insulation tape aswell... just run a small length down the side of the cap for the lead to run down... not that it would be a problem to do but always better to know what needs to be done first. yes i am usually carefull with the soldering iron TBH... the r4580i i just took out (for center and front left) is broken anyway as the center does not work, i took this op-amp out of the blown board i have as the original problem with my main system was the front right was quieter than the front left when i had changed the op-amp over the front right was fine back to same volume as front left... but then there was no sound out of the center speaker... just pops and crackles with no audio at all... where as before the center worked fine... anyway the r4580i i just took out i chipped with a screwdriver... i use a sharp screwdriver to get under it and ease one side up... let the op-amp cool and then do the other side until the legs are completely off the board... then i switch to snipe nose pliers to get the other side 4 legs off... worked well so far but this time it chipped the op-amp on both corners... no worries though as this one was broken... just need to be careful on the next ones as they are going in the blown board (still waiting on tda's)
 
Cheers

 

[jayjayuk]

ok... problem... the first op-amp i changed was for the center/left front and it still does it... which it did not do it before i changed the op-amp... the center was working correctly... now the center comes on... then changes to audio&crackling then if i leave it on it will drop the audio and crackle really loud and bad.. this is only on the center channel... the front left now works fine... i have soldered wires directly on to the pre-amp board and cut the pod out of the picture... so it is not the pod (which i am happy about) but if this still does this with a new op-amp it has me thinking what it could be... possibly the tda? seems to get worse the longer it is run... i have checked the electrolytics around the center OP&TDA and they check out fine... so i am thinking its either SMD components or the TDA ... first thing i will do when my TDA's turn up is take out the center channel and put a brand new on in... if it still does it then it must be SMD... i have been over the solder joints twice over now... i am sure its not a bad joint... do you guys have any input?
 
i am not sure what to think... i did short the pre-amp board on the plate and it blew a resistor but i replaced that and things worked as they did before so i cant see that being a problem as the center did this before the short.
 
i will put the caps back in for the OP&TDA and then just bridge C100 --> WA80 and see if it works... if not then more ta do... if so then probs around the op-amp area.
 
Shame...i thought the new op-amp would sort things

 

[ramachandra]

This is the KW for the lowest price i have found. Taking up 4-5 weeks to get it.
http://www.ebay.co.uk/itm/2pcs-nichicon-audio-capacitor-FW-10000UF50V-/111293035453?pt=LH_DefaultDomain_0&hash=item19e994f3bd
The KA: (I bought many cap from this seller and shipping cost is low.)
http://www.ebay.ie/itm/4700UF-25V-NICHICON-KA-105C-2pcs-/111352316091?pt=LH_DefaultDomain_212&hash=item19ed1d80bb
I bought OPA1602AID in bulk from Mouser around 2.65€ each a while back and the shipping free beyond 70€ to Ireland and they have most of the capacitors. An ideal option for 2-3 people to buy components together.
This seller on eBay had the polystyrene capacitors and he is not selling capacitors this days. Ask, and you may get lucky. The brand Siemens indeed. You do not need to worry about small capacitance difference the 240uF just perfect I'm not sure about the 270uF without a try.
http://www.ebay.com/usr/dos107
The hum look like a ground problem. Maybe the legs are too long and picking up noises, but before you do anything else try to move the cables, the system is more sensitive without the Pod and how you place them is matters.
I put the capacitor into a piece of heat shrink tube a bit longer than the body, so the legs are not contact the metal cover, and no need to worry about short circuit on the PCB.
 

 

[jayjayuk]

ok... there has been many problems on getting these op-amps in... still not done... i am pretty sure two of them came broken as everytime i put the soldering iron on them i check with my finger to see how hot the chip got and i never let it get that hot as i melt the board solder abit first then slide the iron upto the leg and remove... i have once peace on the rear speakers... and i have two pieces on the sub... the track is broken bad for the center/front left but that is no issue as i feel quite at ease with fixing broken tracks. i also broke on of the op-amps as the leg came off it (but it was the one i was moving around and giving abuse to) so now i have one left to put in... maybe me putting it on the center speaker blew on side? i am about to try in on the front right which requires one side only to see if it works... the people who i bought them off are now out of stock... so as of right now i am one down... but the center and FL can wait as i need to do some repairs on that anyway... i think i will wait for the tda's to turn up for that and change the center tda amp as nothing i do can i get that center channel to come on... although it is giving the same effect as the problem i was just having meaning a broken op-amp... but the center is different... when i put an op-amp in on the center it will work for maybe one minute... then it will start popping a crackling... so i will work with that when the tda's arrive... they might take a while.
 
i am just glad i have got the sub working again... one of the new op-amps... i know i dont heat them enough for them to burn.. so all i can think of is bad solder joints? (time and time again... unlikely) or bad op-amp from ebay... quite possible.
 
still more to do... will check back in when i have more done..
 
Cheers

 

[ramachandra]

Is the soldering iron good for chips what you are using? I'm just asking because I have ruined few OpAmps with my ordinary 30W iron when i was far from home and had nothing better to use. The pins are carry the heat quick and a too hot iron overheat them inside under a second. At home i use a temperature controlled ESD safe station on 240 Celsius and low melting point solder. Soldering paste or flux is a great help to create proper joints.

 

[andro6600]

Ok, small update on the mod. I  replaced the 4.7uF 50V capacitor on the pre - amp board with one of my remaining of Panasonic FC 10uF50V105C. I hope that going higher on the uF wont damage in any way the system. I come to conclusion that changing any of the caps on pre amp, result in significant difference in sound. This cap alone made the sound a little more full in the mid-low area, as i said before, the FC are really smooth sounding. The highs are also very pleasant. Somehow the sound became more integrated between sub and satellites. Then, i decide to replace the control pod capacitor with one that i had, some cheap china Sancon 4700uF63V 105C, just experimental. It turns out, that this removed in some degree the fullness between sub and satellites, but not by much. Looks like, the cap tends to tighten the bass, witch is not a bad thing, but still wondering that i like it more. I'll give a caps time to "burn in"(i am not very certain about this thing tough) Eventually i'll order other 4700uF, from reputable manufacture. I want to mix up the brands, to avoid one brand audio signature. What you guys thing about Nippon for that position?
 http://www.ebay.com/itm/1PCS-50V-4700uF-50V-105C-Radial-Electrolytic-Capacitor-19x40mm-/181419680679?pt=LH_DefaultDomain_0&hash=item2a3d74a3a7    are they good? And what about the replaced 10uF cap? Is this going to harm the system (or performance) in any way?
 
Cheers

 

[andro6600]

@ramachandra, i see you mentioned 2 pieces of film capacitors MKT 1uF 63V for the voltage regulators. What is their purpose exactly, and why you decided to use non polar caps instead of electrolytics? Are these a good ones? Because i am about to buy them   http://bg.farnell.com/epcos/b32529c105j/cap-film-1uf-63v-5-radial/dp/1692372

 

[ramachandra]

The Nippon Semicon caps have a well deserved good reputation in electronic industry and some of the series are used for audio purpose, but they are not exactly made for audio, at least not present on the wishlist of the audiophiles. In the past the company have made caps specially for audio an some of them still in circulation on eBay. Because i found no information how this caps perform and they are getting old i give up on them.
http://www.ebay.com/itm/Nippon-Chemi-Con-Audio-Series-Capacitors-4-700uf-25v-Audio-Grade-Caps-/331224512493?pt=LH_DefaultDomain_0&hash=item4d1e84f7ed
 
The standard electrolytic capacitors have effect on the sound of course, but pointless just to pick another and expect a real upgrade, more-less the lifeles agressive metalic sound, poor soundstages description fit to them. Here is the great example:
http://tech.juaneda.com/en/articles/electrolyticcapacitors.html
http://www.head-fi.org/t/528380/electrolytic-capacitors-used-in-audio-dc-blocking-comparison-tread
 
The 4.7uF 50V cap on the preamp board is part of a circuit responsible for the stand by function. I have changed that cap to a 47uF by mistake and cused no harm i can not confirm or deny effect on the sound.
 
I have used the 1uF film capacitors by few reasons istead the same value electrolytes. 1. I have many of them and fit to the board. 2. Film capacitors are usualy better for audio because the more linear frequency and voltage responses. 3. More durable.
Common failure story for PC motherboards: a cap fail belong to the regulator, regulator struggel to sustain voltage for a while than give up and let the unregulated voltage go, processor fry. I found few simalar problems on the broken Z5500 boards so i rather safe than sorry.

 

[andro6600]

Thank you, for your info! It is really helpful to me. About the 1uF film caps, somewhere on the net i read, that the Vishay MKT1822 is a really good one. So i am going to search it. Here is extremely difficult to find good audio parts, and have to order either from ebay, and wait long, or some other stores, that come with a space high delivery prices, to my country. 

 I am very exited and inpatient about this mod, that's why i try every part that is available to me. I am hoping this week my Elnas and Nichicon KG will arrived. 

 

[andro6600]

Is it a problem if i replace 10uF 16V caps on volume control with my 10uF50V? And is it a problem in general, i want to going for a higher voltage caps for all positions, because of lower ESR and higher ripple current? I think not, the capacitor can store only amount of voltage, that specified circuit has given, right?

 

[ramachandra]

The Vishay, EVOX/Rifa, ERO, Wima, Philips film caps have a good reputation for audio in general.
 
The Voltage rating only mark the maximum what a capacitor can safely handle for X hours (described on datasheet). The bigger the difference between the voltage present and the rating is the better, of course not from the size/cost point, just slower ageing, lower ESR.

 

[andro6600]

Ok guys, today i made some more modding. This time not everything gone so smooth. So, i bypassed the TDA caps with 0.22uF 100V MKT Vishay BC
 

 
Then, i replaced the pre amp cap 4,7uF 50V, that is responsible for control pod on-off, according to @ramachandra , with Rubycon RX30 4.7uF 100V, 130C. Also the voltage regulators caps, with Vishay 1822 MKT 1uF 100V. But after power up the system, the fuse blow immediately! I replaced it,  however i forgot to connect the powering wires(red and yellow, removed to be able to unscrew the last bolt from the heat sink) And the pod display became full of bars. Then the VGA connector to the sub, made some sparks, and i turned the power off immediately! It turns out that the one of the lines of the pre-amp panel was burned out! I manage to fix it with some thin copper wires, and solder them. Then i find out that one of the voltage regulators pins is too long, and thought, maybe this is made some short circuit with the heat sink plates. So i cut them shorter. And after powering up the system, everything seems to be ok, but not! After a while, maybe some 20 minutes, the sound unexpectedly stopped, and the display, again was full off bars, and not responding at all. I had to power off from the switch. I decided to bring back the 4,7uF 50V original cap from the pre amp. Thisnot helped either. After ~20 minutes, same story. And now i am clueless?!...  

  What is the problem? Is it possible that the voltage caps are too over the top with voltage? Is it possible the bypass caps are also part of the problem? I know the ramachandra suggest 63V, but i decided that doesn't matter if the voltage is higher. Please help, i do not know what to do now!

 

[ramachandra]

First thing firs. I think you need to progress slower and change only few of the components in one move and do more checking, testing. Because you need to give yourself at least a chance to figure out what is went wrong, than you know where to look.
 
As i see the images i think you had problem a bit under WA200. That is the bootstrap capacitor of a TDA Amp, if that capacitor fail the TDA Apm is blow (ugly) sooner or later, but first can ruin the preamp panel, blow transistors for example. Between the WA500 and WA600 around the 2 pins the PCB look black on the image.
 
Use the diode tester function of the multimeter and search for short circuits on those pins and on the others you recently touched. Do not trust your eyes at all.