Yamaha CDX550E ...after my tweak is much more "Natural Sound"

Yamaha CDX550E and Yamaha CDX750E are essentially the same machine...and I found out they can be really monster killer after few tweak!

Yamaha CDX550E there were plenty of different model in '90s years of these very honest and good sounding  CD player .

Yamaha differently by other brand was experimenting several very different  and somethime sophisticated  DAC , infact you can find inside them Analog Device's chip, Burr Brown ,the well ragarded Philips TDA1541A or in some model you can find Yamaha chip D/A converter such as this forget YM7141.

.....but why YM7141 Yamaha D(A converter was forget, I'm asking myself?!.....probably it was defective or not so good???

....right now it's a rare chip mounted only in 3 Yamaha model and never ever used in any machine again.....is it a real "flop" or is it something like the engine feeded by water, or the almost endless power of some battery disappeared by the marked misteriously??

I was overwhelmed by curiosity and I tried to tweak it after some listening session......

 At first listening it was an honest player , good for its range and category but nothing surprendent, just opensound ,but a little bit flat,light bass, and image not focused perfectly .....was it the DAC to defeat or the project?? I will found out soon!!!

Recapped in some touchy place ( power supply coupling close to op-amp, polyester bypass etc.), redesigned the output , removed the muting transistors,replaced the original op-amp used some carbon composite resistors (Allen Bradley) finally I skipped even the chocke filters that gives a muddy dark sound to this devices ...oohh now the bottle neck of this project is took off and the sound now can fly again!!!!!

Just tried tens of different op-amp to chose the best or whatever what i like more than the others.

I found one of the best could be the Texas Inst. RC5532 , it gaves a tight bass and articulate sound all over the range with a large soundstage , open, and very revealing in detail .

The chosen is really up to the listener ! There are plenty of very good op-amp : Texas, Burr Brown, Analog Devices etc etc....be always carefull to respec the max power supply spec. and  base your chose even on the structure of the op-amp : if it's a FET opamp or a BJT based opamp that makes even a big different in sound!!!! Often BJT opamps works fine in FET design  but sometime FET opamp doesnt works fine in BJT designs.

....and moreover the highly regarded speedy opamp that likes so much to audiophile attendance most of times aren't not so musical ......then my advice is weld a DIP8 socket on your PCB and try  a bunch of smart ones and go for your best!!

good luck and good listening!

continue.....

....I'm listening now at this magical device....I'm not getting mad saing "magical" right now!!! The sound takes body, with a tight bass that really miss before ,before was flatter and muddy, now 3D and bloody detailed without wound your ears ...in one word it is music.....you can hear the breathes, trumpet and sax are rich or armonics , voices so natural , compared to my Luxman DZ121 adopting AD1864 I can't hear any differences now....and Luxman is one of the best devices I've ever heard not modificated.

Happy music toall  with the best tweaking!!!!