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Almi's Logitech Z-5500 Mod (High-End upgrade for the speaker system) - Page 9

post #121 of 131
Thread Starter 



As i experience there is relation between speed of the regulation and heat produced, Watts and size ect. Your impression about the the new regs is normal and you may experience also difference with others. Resistors have effect on the current flow not the Voltage and increasing the resistance will keep the regs colder, but the question is how much interfere with the power requirement of the chips. The TO-220 is big and only good for testing, unless you find a way to keep them cold enough and safe from breaking off from vibration.

post #122 of 131

tda's turned up today... at first they had the listing for 50xtda7294 = £17 .. when i messaged them they said the listing was wrong and before i purchased they changed the listing to 10 X tda7294 = £13 ... so when they changed it i purchased anyway as it was still the best buy i could find on ebay... but when they turned up today there was actually 50 X tda7294 which only cost me £13 :) so worth the wait as now i can do both boards... i will purchase some 0.47uf's for the third mod in next couple of days and wait for them to turn up and get back on this again... i put some 0.1uf caps on the op-amps rails and now it comes on for second and then goes straight off... so i removed all the extras i put on and will wait for the 0.47uf's and then start checking all the components again... its weird how not just one channel goes off like one channel either op-amp or tda is over heating... it all just shuts down and all i have checked so far is if there is voltage going to the op-amps... the situation got alot worse when i put the 0.1uf caps on the op-amp rails... wont be doing that again... i will be going for the bypass on both boards... if checking all the other components does not turn up any results then i will bypass the op-amps and check again... if still the same i will be putting a full new rack of tda's in as i have enough of them now.

post #123 of 131

Ok, new problem. Today i replaced 22uF with Elnas, and bypass them with 0.22uF 100V Vishay. Everything was good, but after power on the sub, the control pod didn't turn at all!!! What is wrong now? The power supply make this buzz sound, so i am guessing that it is working. 


EDIT: So i figured out. It was blown resistors of the regs. I find that one of the legs on the two regulators, the tracks under them was broken.( I knew that's going to happen, because of the heat sinks) So i manage to fix them soldering direct to the one side of corresponding smd, then used moment glue to stabilize them more. For now, i am gonna leave that way, until final completion of the system. Here some pics: 




I wonder, is it a problem, that two heat sinks are connected to the side ones, because the plate of the regulators maybe can make a short circuit? On the +18V, plate is ground, but on the -18V is input? Is this gonna cause some problem?Do i need to isolate the aluminum buses(maybe some painting) to prevent the eventual short? I kinda like them that way, because they dissipate some extra heat to the sides.

Edited by andro6600 - 7/11/14 at 10:38pm
post #124 of 131
Thread Starter 

I'm impressed about the way as you managed to keep the heatsinks in place, and you found a good size too to keep the regs cool enough. The board is almost complete. Nice job! :smile: The negative regulator need an silicone insulator indeed. The sinks look stable enough still better to not underestimate the Sub. If you connect the two sinks together it will minimize the vibration, and the stress on the copper tracks. A U shape metal strip between can do the trick. What do you think about the sound with the Elnas now? As i see the pair Nichicon KG is arrived and in place too.

post #125 of 131
I considered too, putting the strip between the sinks, but thinking of plastic instead of metal, just to be sure that no shorts can occur, even the sinks are anodized.
About the sound. Man, i can't explain how much i am impressed! First thing that blows me away, was how good is separation of the channels. Everything is positioned perfectly, the difference is almost the same as with changing the opamps! Insane! :-) In the lows, things become even clearer than before, some little deepness added, and you were right, that Elnas will fix the problem with the low mids of the satellites. Now there is more thickness in that frequency range, and this helps for the better integration between sub and sats. And while before, sounding was kinda loose, wich is nice sometime, but the definition was not there, now it is very tight and the definition is outstanding! Especially with the movies, effect is even more! Nice! And the last, the timber. Every instrument sounds much more accurate and natural. Somewhat everything is more musical! To sum up things, presentation of the system is quite close to the headphones filling! I love it now! :-)

Sent from my C6603 using Tapatalk
Edited by andro6600 - 7/9/14 at 5:57am
post #126 of 131

Very nice work! Respect... Maybe i will do some modifications too. But first I want to put the z-5500 in my car.
My plan is to put the power stage out the box, to take the sub membrane? Out and fix it in the back of my car, and use the case as subwoofer (:

Maybe I will use the other speakers too, or at least a part of it...
I think I need the pre-amplifier stage for recieving analogical signal.

But, my first questionning is about power supply. What is the best way to feed the amplifier with a car supply at 12V DC?!

And can I shunt the digital section and only use analog input? Without the pod and the rotary button?
Can I regulate each channel gain/volume directly on the pcb with variable resistors?

I you have some schematics of the power supply section, or any informations about my project, thanks a lot I'm, not really electronician, but more from electrical side. I have a bit lnow-how it works, but not enough to have fully clear seeing... ((:

Sry for the bad english...

P.s: I live in switzerland under 230V/50Hz

Thanks for help
Edited by ganjouille - 7/15/14 at 1:17pm
post #127 of 131

@andro6600 i thought about the same thing... to put the sub into my car... they way i thought of doing it was either by using an inverter to step the voltage up from 12v to 240v and use the 240v in as usual into the sub (as long as the inverter has the correct current capability to handle the load (on the back of the sub i THINK it say 1.5A) or the only other way i was going to do it was to wind my own transformer (which i would really like to do for some reason :) ) use some big thick wire and put quite alot of turns on winding and then calculate how many turns on the primary side relative to the amount of turns on the primary side to give me the voltages needed... i dont think it should be to hard... i know for definate there is an 11.4v tap-tap (on its own) and i think the other is somethings like (would have to check) 16.? to center tap, so from 16-0-16 which gives 32v (now i think it is more than 32v but those voltages would need checking... they are written on the transformer anyway so would be a case of looking. they are the two ways i was going to go when i had finished my sub.


yes you can bypass the control pod using the pins on the d-sub connector 6-7-8-13 then solder rca's to the correct pins for the line in (using pin 13 as the ground for the rca's) this is what i was going to do.


i read something online that a car sub is different or the frequencies are cut differently because it is a car and the shape of the car relative to the seating positions... so they can actually use higher frequencies to create lower frequencies by the time you hear/feel it in the seating position... you maybe want to read up a little bit on this first... i read a few pages when i was looking for a replacement sub for the second board as i have the box and amp but would need a sub, then i read that as i wanted to know if i could use a car sub instead. just a thought before you go slamming it in... this logitech rattles everything in my house.. the staircase... the wardrobes upstairs... the girlfriends temper :) so you might be sat at some traffic lights and you go to move of to find your wheel bolts have vibrated out and your wheels fall off :) hahaha



post #128 of 131
Thread Starter 

This is what i found about the original Z5500 transformer:


Input: AC 120V or 110V 60Hz. (US version)

Output:26.2V-0V-26.2V(5.7A) +14V-0V(0.5A)

Power: 300 W /VA

Dimension :115mm Diameter x 45mm High



Other than the input the rest should be the same for the European.

Edited by ramachandra - 7/16/14 at 6:58am
post #129 of 131

yes i had the voltages wrong... i had a feeling they was wrong... i have another toroidal transformer which i must have remembered 11.4v from. yes mine is 240v... i would match the output voltages and the current capability for each output and it should fire up in a car.

post #130 of 131

Ok guys, my mod is finally complete!  :smile: Here are full modifications i made to the system.


First, replaced satellites with Yamaha NX-E400 for the front, and NS-P60 for center and surround.


Then i replaced speaker for the sub with Pioneer TS-W260D4, witch is one of the most significant upgrade sound wise.



And i put some extra damping in the closure with cotton wool, with careful listen to the effect and needed quantity. This is also VERY important to the overall sounding in the lows, and even for my surprise, the difference was huge!

This two upgrades, took the system from barely usable for music listening, to a comfort state. Good!


WIRING: Change the thin cables to the sats, with professional Proel Speaker cable, AWG 14  http://www.musicworld.bg/en/c_2288/i_2466/Proel_HPC740.html

which brought some nice detailing of the sound.


Also replaced internal wiring of the sats with this one. For the sub internal wiring, i used same cable but AWG 11. Now i am sure that the system runs some quality cables.


RE-CAPING: The POD: Replaced everything except the analog in caps with Panasonic FC/FM series, with doubled voltage. The op-amps for analog out are TI OPA2134.


The AMPLIFIER: Everything on the main board with Elna Silmics. For the main filters - Nichicon KG. Op-amps TI OPA1612AID - incredible improvement! On the Pre-amp for the front speakers used Wima MKS2, for the center and surround K-73 16, because fronts were too bright, and Wima caps are more thick and round sounding, this way i made them more similar to sound signature of the rest. 





Also, replaced all resistors with metalized ones, at 0.6W, and voltage regulators with TS7818CZ and TS7918CZ, and managed to cool them well enough. Also replaced mica sheets of the TDAs and new termal paste. About the bypass caps Vishay MKT, i decided to leave them out of busyness, because they made the sound somewhat restricted and lack of refinement of the Elnas. As is seen, i stabilized all caps with hot glue.


And last, i re - cap the crossovers of the front satellites with polypropylene Mundorf. Because of the sound signature difference between surrounds, i decided to change cross frequency, and lower the value of the caps from 8.2 to 6.8uF and 3.3 to 2.2uF to lift the frequency a bit higher, and now the sounding is more matched, and also i find them better sounding this way.


So! After many hours of work, reading on the net, waiting components, millions of times opening and closing the box, soldering, desoldering things, the final result is AMAZING! The system now has real high quality, at par with at least middle class AV system, or dare to say, maybe a little better from some. Overall sound is rich, modern, detailed, powerful! Real pleasure to listen! Thanks to you guys @ramachandra and @jayjayuk! Thank you for the help, and responsiveness! Wish you well! :beerchug: 

Edited by andro6600 - 7/22/14 at 9:38pm
post #131 of 131
Thread Starter 

Now that's what i'm talking about!


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