Ok guys, my mod is finally complete! 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!
Edited by andro6600 - 7/22/14 at 9:38pm