Hi diyers, thanks everyone in advance for your help in general when building this machine, so now is finished and i'm really satisfied with it i'm gonna tell you the story of the SL-P520 who could!
When i first got the CDP it was a complete wreck, when plugged in only the LEDs on the tray will light up and the pickup started looking for focus infinitely, consequently smoke start coming out of the power supply part.
After cleaning (it was massively dirty) electronical inspection begun... oh the horror...
[IMG]https://thumb.ibb.co/nEx306/2.jpg[/IMG]
There had been work on it some time ago... and it was a real nasty job, power transformer had some work, a diode was badly replaced, and worst of it, the PCB was mismounted which led to have some massive cracks... i could not leave it suffering like that so hands to work...
Well now it's alive... and reads any cd perfectly... sadly, the smoke on the power supply part at the beginning was a shorted -32v supply which supplied -37v to the display burning it to the point where it was unreadable (Thread here: [url]http://www.diyaudio.com/forums/digital-source/312603-vfd-dim-technics-cd-player-sl-p520.html)... Sourcing a new display is possible but since i'm on Argentina, get it here was imposible, so i just wired up another similar display from a Panasonic CDP and got something more than acceptable, also a new tray front cover was made since the original was missing. LEDs on the tray also look very tired and replaced them with new shiny white ones.
[/url]
So well it's alive and on factory specs it reads wonderfully... but is far from beign a collectible, and also far from sound amazing...
So... here comes the fun part, using the knowledge from modding my Portable CDP Technics SL-XP5 (Thread here: http://www.diyaudio.com/forums/digital-line-level/284831-tda1305-requirements.html)which is schematically the same player as this... they share the same ICs... (still amazed how they achieved that), i decided to completely rebuild the audio stage with TDA1541 and a discrete output
After removing old DAC, reconfiguring the digital filter and scoping the signals to check everything is correct is time to build the DAC, i used a 74hc164n in order to convert the Japanese formatted signal into I2S.
https://ibb.co/bTVCtR
https://ibb.co/hegJYR
After testing it with just resistors for I/V bridge the sound was really good but had no gain, so it was time to build the gain stage... i did not want to use OPamp and tubes are expensive, so i choose transistors, the simpler the better, found on lampizator website his Fet-Ishizator... an extremately simple single Jfet transistor Class A output stage... how can that be beaten...
https://ibb.co/b8W7Sm
The final approach was to find the correct coupling capacitor to remove DC , i started with a 100uf Nichicon muse, didn't like, tryed smaller caps, till found the one, Elna Duorex 4,7uf proved to sound wonderful.
Also taking advantage of the remaining components i replaced the 5218 Opamp of the headphones output with the remaining LM833.
So.. how does it sound? it sounds amazing, Technics players are excellent in getting every bit of audio extracted of the CD, the digital filter is also an extremely good performer, is the same used in SL-P1200 and 1300, for TDA1541 theres not much left to say that hasn't been said, and for fetishizator... i still wonder how such a simple thing sounds so nice, since is Jfet the highs are completely there, and bass well... i did not know that my headphones can have that kick...
So well... that's the story of the SL-P520 who could... now i'm looking forward to cosmetic modifications since it looks really banged up, thinking on stealing the Pioneer Elite look when i find someone who can remake the silk print.
Thanks all for reading this, and keep modding things to make it sound!
When i first got the CDP it was a complete wreck, when plugged in only the LEDs on the tray will light up and the pickup started looking for focus infinitely, consequently smoke start coming out of the power supply part.
After cleaning (it was massively dirty) electronical inspection begun... oh the horror...
[IMG]https://thumb.ibb.co/nEx306/2.jpg[/IMG]
There had been work on it some time ago... and it was a real nasty job, power transformer had some work, a diode was badly replaced, and worst of it, the PCB was mismounted which led to have some massive cracks... i could not leave it suffering like that so hands to work...
Well now it's alive... and reads any cd perfectly... sadly, the smoke on the power supply part at the beginning was a shorted -32v supply which supplied -37v to the display burning it to the point where it was unreadable (Thread here: [url]http://www.diyaudio.com/forums/digital-source/312603-vfd-dim-technics-cd-player-sl-p520.html)... Sourcing a new display is possible but since i'm on Argentina, get it here was imposible, so i just wired up another similar display from a Panasonic CDP and got something more than acceptable, also a new tray front cover was made since the original was missing. LEDs on the tray also look very tired and replaced them with new shiny white ones.
[/url]
So well it's alive and on factory specs it reads wonderfully... but is far from beign a collectible, and also far from sound amazing...
So... here comes the fun part, using the knowledge from modding my Portable CDP Technics SL-XP5 (Thread here: http://www.diyaudio.com/forums/digital-line-level/284831-tda1305-requirements.html)which is schematically the same player as this... they share the same ICs... (still amazed how they achieved that), i decided to completely rebuild the audio stage with TDA1541 and a discrete output
After removing old DAC, reconfiguring the digital filter and scoping the signals to check everything is correct is time to build the DAC, i used a 74hc164n in order to convert the Japanese formatted signal into I2S.
https://ibb.co/bTVCtR
https://ibb.co/hegJYRAfter testing it with just resistors for I/V bridge the sound was really good but had no gain, so it was time to build the gain stage... i did not want to use OPamp and tubes are expensive, so i choose transistors, the simpler the better, found on lampizator website his Fet-Ishizator... an extremately simple single Jfet transistor Class A output stage... how can that be beaten...
The final approach was to find the correct coupling capacitor to remove DC , i started with a 100uf Nichicon muse, didn't like, tryed smaller caps, till found the one, Elna Duorex 4,7uf proved to sound wonderful.
Also taking advantage of the remaining components i replaced the 5218 Opamp of the headphones output with the remaining LM833.
So.. how does it sound? it sounds amazing, Technics players are excellent in getting every bit of audio extracted of the CD, the digital filter is also an extremely good performer, is the same used in SL-P1200 and 1300, for TDA1541 theres not much left to say that hasn't been said, and for fetishizator... i still wonder how such a simple thing sounds so nice, since is Jfet the highs are completely there, and bass well... i did not know that my headphones can have that kick...
So well... that's the story of the SL-P520 who could... now i'm looking forward to cosmetic modifications since it looks really banged up, thinking on stealing the Pioneer Elite look when i find someone who can remake the silk print.
Thanks all for reading this, and keep modding things to make it sound!
Hi! thanks, how many hours... hmm they were a lot... most difficult part was getting it to work again so many tests and trials, for a time the diagnostic was dead CPU, i guess to get it to work is close to 50hs, like 5hs more to the display and cosmetic, and some 10hs extra for the DAC i've should add the hours spent on the XP5 to get the knowledge on how the digital filter works, that was a lot of time, close to 100hs of cracking up my head... back then i didn't have a scope, it was just trial and error...
About the PCB pics, sure:
]That page doesn't exist (404) - imgbb.com
]That page doesn't exist (404) - imgbb.com
]That page doesn't exist (404) - imgbb.com
]That page doesn't exist (404) - imgbb.com
Same pics as on the post but good size, schematic is really simple, just followed the one on TDA1541 Datasheet, using the caps i wanted for decoupling, the caps on the back are just in parallel to the power supply, and for the data, the howto on the 74hc164n i took it from lampizator website, specifically the NOS mod for Sony 227ESD, and for the Technics info i used the previously posted on the SL-XP5 thread... everything was pretty straight forward.
Let me know if you need some more help and good luck modding!
Sure, the one who described more humanly was Lampizator over here
sony227ESD
Let me know if you need extra help!
Brilliant, that's a useful little circuit ! Many thanks.
Anyone got a circuit for the other way around?!?!?
P.
P.S. Mr. Lampizator does some great work but how he gets anything to be anywhere near quiet with all those wires everywhere I don't know !!!
Hey! in order to do the other way conversion is the same, except that instead of delaying LRCLK you delay DATA, i've used it (don't remember why or where) and works fine.
And yes, see the Lampizator work is kind of cringy, on the Behringer ultramatch (or sth like that) he removes the SPDIF coil filter with plyers... on other mods he just rips the resistors in half with wire cutters to isolate the circuits...
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.