Philips cd-471 mods

[Magura456]

Did you actually do much of a comparison Magura?

No, not yet. If i can find another player, i can make a comparison.
The most important thing is, that the ugly plastic box produces (for me) very nice music. 😉

 

[SoNic_real_one]

They found about jitter issues of SAA7220 in 1993:
http://www.n.mackie.btinternet.co.uk/audiocircle.org/cd-jitter.pdf

 

[padamiecki]

fabric error, bad connection on the original pcb?

Hi
let me warm up the thread:
I am happy owner of moded CD471
but I found that my model has fabric error:
the positive leg of cap 2345 (or 3331 - cannot remember now - arrow on the schematic) is connected not to the ground but to +5V rail.
- Could you check if your 471s have the same failure?
- How do you think, repairing this failure will result in better sound?
thank you in advance for the answers🙂

 

[Magura456]

Hi,

I'll check it this week. What do you mean by fabric error?
Does it play cd's, is the sound not good?

 

[padamiecki]

explanations

Hi,

I'll check it this week. What do you mean by fabric error?
Does it play cd's, is the sound not good?

fabric error was for me a mistake during designing the pcb.
please look at the pics.
on the schematic (last time i sent wrong) positive leg of the cap NO 6230 should be connected to the ground.
but please look at the second pic, the positive leg of cap NO 6230 is connected to main output of +5V reg chip - try to check it with multimeter😀
My idea was to unslolder this leg and solder it to the top pcb (the ground).
Beside of this the sound is great (as you could see I used SEPC caps and WIMAs) for tweaking.

 

[padamiecki]

finished

here are the latest results,

let me introduce the mods from the beginning:

1. rebuilding to nonos
2. changing 7805 to LM2940L5001
3. paralleling main caps from power supply
4. throwing out ceramic 100n decoupling DAC caps from TDA1541 with WIMAs 470n/63V
5. changing the most crucial caps from digital part to OSCON SEPC
6. throwing out current eater headphone opamp
7. throwiing out output mute transistors and other parts
8. connecting output caps directly to output chinch sockets
9. taking the output from the 1st leg of the first opamp (throw out the second filter, throwing out 2k4 res 3641 and 3640)
10. paralleling output caps with 2u2 400V DC WIMA MKPs
11. adding extra analog power supply decoupling caps (those gold nichicon FGs) and paralleling existed with 470n/63V WIMAs
12. OPA2134A instead originals opamps
13. connecting positive leg 2630 cap to the ground (see the picture) instead to +5V DC p supply

I have to admit that most of the tweaks were done long time ago.
today I changed:
- old opamps to 2134s,
- installed extra decoupling caps Nichicon FGs to 2134s
- resoldered the positive leg of 2630 cap to the top groundplane
- lubricated holdfast of the cdm2.

Now it is hard to say which today mods were the most important but
I have got new quality of trebles.
Now They are much more delicate and clear, with tonal reachness, light metallic sound was gone.

with every minute of playing it is getting better and better😎

 

[padamiecki]

I can see that nobody here told that rebuilt 471 to non-os? this is the shortest way: http://www.goldfinch-mod.eu/CD/marantz cd40/nos.gif
and here more on nonosing http://lampizator.eu/Nonoversampling/NOS.html

 

[Magura456]

Hi pawel,

Nice tweaks! I want sanyo oscon sepc for some critical places...but can't find them easily 🙁
Are you finished with tweaking your cd 471? 😀

My next tweak is a new low noise reg for the sa7210.

 

[padamiecki]

Hi pawel,

Nice tweaks! I want sanyo oscon sepc for some critical places...but can't find them easily 🙁
Are you finished with tweaking your cd 471? 😀

My next tweak is a new low noise reg for the sa7210.

yes I think I am finished with 471🙄 maybe not😉

I am hunting for Philips CD8400 mkII or Fine Arts 9009 now for final cd.

Could you confirm the information about C2630?

thank you in advance

 

[JOSE BEMBIBRE]

here are the latest results,

let me introduce the mods from the beginning:

1. rebuilding to nonos
2. changing 7805 to LM2940L5001
   /QUOTE]
   
   I know that I´m late, but just in case that somebody follows this recommendation.The LM2940 is a very prone to instability unless you set the proper caps (22 mF with ESR below 1 ohm and greater than 0,05 ohms).
   Just check.
   Rgds.
   Jose