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13 Feb 2020

Toshiba XR-9128 .... a great job!!!!


Toshiba XR-9128 




.........essentially is the umpteenth Philips based CD Player based on our TDA1541 and the very good CDM-4 laser mechanic ..... ...the knight and his trusty horse!!!




... the finished job!!!



...original PCB...

...Power supply completely recapped

IT


...work in progress


...drilling to stole the 220V









...HV Power Supply




ll


...tube PCB with cathode pampered by 3 cap parallel to keep the max tonal richness and detail....the same for decoupling caps...




THE INTERCEPTOR





... This is what I named "interceptor circuit"


...stoling signal directly from TDA






























...the alu bracket to set HV power supply and sheld it from display!














How does it sounds??!
After  the mandatory warm up notes flows so natural and clean to your ears that you just can't believe it!!!!
What I hear is great coherence  and richness of details....you can hear very easily Paco de Lucia touching the strings or Patricia Barber wispering to microfone or feeling in your flesh the tonal richness of Sade's voice .....but what is different from the many  TDA1541 I modified in all these years???! 
I did not use an SRPP triode configuration that likes soo much at my friends Marcus Fikus, but it's even true that it's not the first where I adopted  a double common-cathode amplification stage and filter...and so......
.....the main difference is converting TDA1541 Iout in a very small signal by mutual different kind of resistor ( carbon composite+metal film) and capacitors ( low-ESR electrolitics+Tantalum back to back +polipropilene) to obtain much more more dinamic and refined signal and making work TDA1541 wich is a current generator in the easiest (and the best) way is possible with the lowest load possible over its I-OUT pin!!!! 
The trouble of designer now is to obtain an high gain output stage to lift signal OUT around 5V peack to peack and keeping an acceptable low noise , and...................I succeded!!!!!! 
The easiest way for a designer to work with TDA1541 or similar chips is to obtain an high output value from TDA1541  with wrong and too high load in TDA Iout wich is the easiest way to keep noise low, adopting a low amplification module , but spoiling at all the signal in every its parameters: first of all high distortion and dynamics very limited and a worst soundstage and coherence!!!
OK,many on-line design just works!!!....but how do they sounds .....but quality?????!!!!!Better don't believe too much in forum enthusiastic forum comments before to try and to listen at the result!!!!
Another kind of modifications are the ones to keeps all original stage (OPAMP INCLUDED!!!) adding a tube buffer after a poor opamp output stage design, pretending all is great now!!! 
That's FUNNY!!

I work in another way, and fortunately  still  several people do, avoiding easy shortcut!

The results comes clear to my ears: Increased dinamic at all, amazing precision on high frequencies , amazing sharpness and much more deep and controlled bass by the use even here and there where it was possible even tantalum caps!
This is all but not boring to listen at all comes to life and all veils are over!!!!!!!!! 
This would be a Maoaudiolab SE version!

a short listening session

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