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-   -   Marantz CD-50 and CD-60, TDA1541, CDM4/19 (https://www.diyaudio.com/forums/digital-source/201057-marantz-cd-50-cd-60-tda1541-cdm4-19-a.html)

Mayday 11th January 2012 11:00 AM

Quote:

Originally Posted by candrei (https://www.diyaudio.com/forums/digital-source/201057-marantz-cd-50-cd-60-tda1541-cdm4-19-a-post2856382.html#post2856382)
I have the manual and I will post today some pictures of my work.

Looking forward to see the pics :)

Do you have the TDA1541 re-clocking PDF too? A lot of usefull info in it.

quan 13th January 2012 09:22 AM

Hi guys, been reading the thread with interests. I am unable to locally source for DEM cap. Can anyone suggest a source?

UV101 13th January 2012 09:37 AM

RS are in have branches worldwide inc Australia.

120pF Panasonic PPS cap SMT 0805

https://img-asia.electrocomponents.c...R414692-01.jpg

Mayday 13th January 2012 10:09 AM

Or these suggested by Andrew I think earlier in this thread.

180pF Silver Mica

UV101 13th January 2012 10:20 AM

I'd use close tolerance PPS over silvered mica for this application. Also, the original cap is SMT in this player and the leads can be kept extremely short (even attached to the pin legs) which is more likely to effect performance than the cap type (within reason).

Mayday 13th January 2012 10:29 AM

Quote:

Originally Posted by UV101 (https://www.diyaudio.com/forums/digital-source/201057-marantz-cd-50-cd-60-tda1541-cdm4-19-a-post2859759.html#post2859759)
I'd use close tolerance PPS over silvered mica for this application. Also, the original cap is SMT in this player and the leads can be kept extremely short (even attached to the pin legs) which is more likely to effect performance than the cap type (within reason).

I'm sure you're right. I have only tried Silver Mica, so I can't say one way or the other. :)

Mayday 13th January 2012 02:01 PM

Read about a rather interesting mod(the article was about CA D500SE).
The author cut the traces for PS to the IC's and soldered in a 0,8mH inductor in series with the supply. He used 0,8mH because he had some laying around, 1mH is apparently what "should" be used. This mod should take care of some of the RF noise.

Opinions fellows?

UV101 13th January 2012 02:17 PM

Use seperate regs for everything then you dont need them!!!!!!!!! :-)

Look at page 1 on the CD63/67 mod thread. In Ray's PDF's he's using inductors with ferrite beads on all shared supplies. It was something I did initiall but removed as more PSU seperation was installed. The are primarily used in an attempt to isolate noise. With individual supplies, you dont have lots of other devices on the rails contributing to "global" noise. In the CD50, there is a 4.7u inductor on the 5v rail fro the 7310, a 1r on the 7220 (which would have been bypassed with the introduction of a seperate reg and 3 x 10r on the TDA rails. The resistors are for the same reason as the inductors are being suggested.

Inductors are better than resitors but seperate supplies is the way forward!

Next little tip..........

Look at the HF into the 7310...... not sure how easy it is in the CD50 but I would look at replacing the compnents connected to pin 31 & 32. The 2n2 would benifit from silvered mica if it can be made to fit (it will be quite big!!)......

Mayday 13th January 2012 02:31 PM

Quote:

Originally Posted by UV101 (https://www.diyaudio.com/forums/digital-source/201057-marantz-cd-50-cd-60-tda1541-cdm4-19-a-post2860078.html#post2860078)
Use seperate regs for everything then you dont need them!!!!!!!!! :-)

Look at page 1 on the CD63/67 mod thread. In Ray's PDF's he's using inductors with ferrite beads on all shared supplies. It was something I did initiall but removed as more PSU seperation was installed. The are primarily used in an attempt to isolate noise. With individual supplies, you dont have lots of other devices on the rails contributing to "global" noise. In the CD50, there is a 4.7u inductor on the 5v rail fro the 7310, a 1r on the 7220 (which would have been bypassed with the introduction of a seperate reg and 3 x 10r on the TDA rails. The resistors are for the same reason as the inductors are being suggested.

Inductors are better than resitors but seperate supplies is the way forward!

Next little tip..........

Look at the HF into the 7310...... not sure how easy it is in the CD50 but I would look at replacing the compnents connected to pin 31 & 32. The 2n2 would benifit from silvered mica if it can be made to fit (it will be quite big!!)......

Just thought of it as a general tip if someone doesn't want to go through the effort w separate supplies.
Of course separate supplies will be superior, but it's a usefull tip for people who want to take the slightly easier way.

Will look into the silver mica suggestion. Thanks :)

UV101 13th January 2012 05:14 PM

Its good practise to use inductors instead of resistors however......

seperate 78xx/79xx will only cost pence and will do a far superior job of creating seperate noise domains. They are very easy to fit. Usually on mods I do, I remove the supply resistor & fit a 7805 to the main cpu just to get its own noise off the main rail (its very noisy!).

Take a 7805, solder a wire to the supply (in) leg and bend it upwards around the front of the reg. Bend the middle leg forwards at 90 where the leg narrows and cut it short (about 3-4mm after the bend). Where you have removed the supply resistor, fit the output leg through the hole in the pcb that connects to the supply pin on the chip and make a note of where the middle pin contacts the top screen. Ensure it touches nothing other than the top screen. Remove the reg and scratch the top screen surface to key it for soldering. Solder a blob to the screen, re insert the 7805 and solder the middle bent leg to the screen - this is gnd. Solder and trim the output leg. Finally connect the wire to the + rail for the main smoothing cap before the main 5v reg.

This principle can be repeated throughout the player in place of supply resistors. You will to a large extend separate the noise of each individual supply from the others in the player. As and when you have time and , you can replace each 7805 for something more exotic.

This picture shows this principle applied to the driver IC's running +/-8v independently in a CD63. Note, from left to right the pos reg is In,Gnd,Out and for a neg reg its Gnd,In,Out ;)

https://i497.photobucket.com/albums/...s/IMG_6040.jpg

Trust me, its worth doing for everything!!!:wave:


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