Monday, January 31, 2011

Modding/Upgrading Marantz CD50

Other mods to this player:
part 1 (this paper)
part 2
part 3
part 4
part 5

A month ago I got hands on one of the Marantz middle lineup cd player - Marantz CD50.
Sure its stock sound is kinda dull although it has one of the best DACs - TDA1541A.

*) UPDATE (06 Feb 2011): Today we made a blind listening test with 2 other guys comparing my moded Marantz CD 50 vs. stock Sony 337ESD vs. Kenwood DP7010
Everyone was surprised - moded Marantz CD 50 outperformed all of the others easily. You cannot image the difference. Even though the Sony sounds very very good, too.

After reading a lot of forums, blog posts etc. on the internet I finally ordered all the components I needed for tuning my player.
- a bunch of Os-con capacitors 330uF/6.3V I found them as the cheapest Os-cons on ebay today
- new LM2940CT-5 regulators 2pcs (will be used later on for special power supply to main digital chips)
- some WIMA MKP 0.47uF
- new op-amps Burr-Brown OPA2604
- and some tantalum capacitors

So I started.

* click on the pictures for better view

1) See my mighty Marantz CD50

2) First I Os-coned the PCB. All major capacitors in the digital and analog part became Sanyo Os-con.
TDA1541A, SAA7220, SAA7310 in the digital part
OPA2604 in the analog part (which will be put in the place of the NE5532)
all of then got Oscons 330uF/6.3V
Yes, 6.3V is okay as all of those chips work with 5V power supply. I will be better if the caps ratings were a little bit higher let's say 16V, but they are almost twice the price of 6.3V, so I decided that these will be fine.

3) It was time to throw again the stock op-amps. They are crap! And put the new OPA2604, which are FET op-amps much much better!

4) Then I added new decoupling capacitors to the TDA's bit pins - 14 x WIMA 0.47uF MKP.
And also bypassed all vital power caps - all new Oscons and capacitors in the main power supply. This simple filter make a huge difference in my opinion.

I also bypassed the main 5V regulator chip (7805 family) with a tantalum 100uF/25V from input leg to ground. This is vital because tantalum capacitors are fast and they put their charge into play exactly when it is most necessary.

5) This time wanted to put into play a NOS mode, too. Non OverSampling. For those who do not know what it is - this is a change in which one of the chips (SAA7220) is being bypassed, because it does oversampling and filtering and thus changes the sound.
And I have to tell you - it's a killer mod! The results are real and you will hear.

- Locate the "LEG 1"/pin 1 on the underside of TDA1541 and SAA7220 chips
- on SAA7220 cut both traces as close as possible to legs 15 and 16
- on TDA1541 cut trace as close as pos on leg 1
- using a thin wire connect the TDA1541 and SAA7220 legs 1 to 1, 2 to 2, and 3 to 3.
- connect the SAA7220 leg 23 to the other chip - the de-modulator chip SAA7210 leg 11.
* In case of the Marantz 40/50/60 - there is a newer chip - the SAA7310 - a square black spider with 44 legs - 11 legs on each side of the square. The mute pin is leg 18 (which looks like floating/not connected)
* In case of the SAA7220 and SAA7210 chips - if the mute trick does not work, you must float (isolate) the leg 11 on SAA7210 before connecting it to SAA7220P 's leg 23.
* for more details look closer into the images, I have put explanations there.

6) Make sure you have put all new elements correct - preserve polarity on the electolite capacitors!

7) Connect the player to power line 220V and be ready to unplug the cable if something smokes or bangs ( if you have connected your new electolite capacitors - Os-cons - with wrong polarity they can explode, but do not worry you will change them again ;-) )

If everything is fine for 10 minutes ... connect to your amplifier and listen.

That's it! Sit back, take a whiskey and have a great time listening to your favourite songs!