Thursday, March 31, 2011

Modding/Upgrading Marantz CD50 - part 4

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

My final ideia for this player was a custom dedicated power supply regulators for the 2 most vital receiver chips - SAA7310 and SAA7220P/B.
I decided to use the upmarket version of 78xx regulator - LM2940CT-5, which is not so much noisy as the 78xx family and is easy to deploy on a PCB.

Here is the schema I used for the PSU regulators. One this I should notice is that you should use tantalum caps or premium grade ones, low ESR.
For the 2200uF I have got 2 x Elna Starget which are low ESR caps and good for audio.
1uF cap is Kemet tantalum - very fast capacitor! and with low ESR again
the 220uF caps are again Kemet tantalum but old stock in big corpus
and of course close to the chip we have 330uF Sanyo Oscon SEPC (this one is on the PCB of the player).

You might wonder why there is a 1R resistor in series. That was taken from the original Marantz design. It forms a Low Pass Filter with the Sanyo cap thus eliminating a low of the noise from the stock 7805 regulator at the cost of resistance.
That's okay in my opinion for this class of CD player. So I kept the resistors because the sound was better also checked by ears.

*) download power supply schema

Power regulators' board which will be installed in the cd player

Power regulators' board back

New power board installed (bottom view)

Stealing points for power line of the power reg board

Closer look to new power regulation board

Power connection for SAA7220P/B chip on 24 pin leg

Power connection for SAA7310 chip on 28 pin leg

And ... that's it! I am done with this marvellous cd player!
It has everything that can be upgraded and sings like a pure natural reality.

I hope these articles will be useful to someone and if you have questions please leave me a comment below.

Wednesday, March 30, 2011

Modding/Upgrading Marantz CD50 - part 3

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

This part is dedicated to player's clock!
The one and only mighty clock that everyone is talking about so much.

My personal opinion is that it really matters. But it matter in a way that it has a separate power supply with separate transformer.
Yes there is difference between a clock for 40$ and for 200$ but that difference is not as much as everyone thought.
If your cd player costs 100$ there is no point spending 200$ for a new clock, a 40$ bucks clock will do a perfect job. And yes - if your whole system is an expensive one (over 4000$) it's most probably that you will hear a noticeable difference between cheap and expensive clocks.

But let's focus in our case on a 40$ bucks clock right away from eBay (Hong Kong seller).

First thing (I've already mentioned it) is that you must use a separate transformer. A 5-10V@100mA output is perfect choise. Small and producing enough current.
You must know that correct and stable voltage is the more important than the current produced by the transformer (of course we should have enough at least the minimum required mA).

First let me show you what I ordered from eBay for 36$ (including shipping)

I must admit that this clock is worth every cent even though it is cheap one!

Now you can see how I have installed it within the Marantz cd player

To connect it you should first remove the old crystal along with the two capacitors bounded with it and connect the new clock at the XIN pin of the receiver chip. Please see the photo for better understanding.

Woala! You are ready, set and go! :) Plug in all the cords from the amplifier and power line and listen!

An hour after installing the new clock I decided to upgrade all capacitors in the power supply. So here are some picture describing it.

Done for now! :)

Modding/Upgrading Marantz CD50 - part 2

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

Almost 2 months ago I made a stunning mod to my Marantz CD50 player.
Later on I decided to make some additional changes after my satisfaction with the first mod.

*) Downloads

1) AC RFI filter to the 220V power line right before the transformator.

AC power stealing points for the RFI Filter

I have used a well known schema which is really working and you will hear difference.
The L1/L2 windind is actually two wires wound tightly around one ferrite air core together 10-15 times (not like on the drawing, but both wires side by side ).

RFI filter installed in the CD Player

2) Switching to Blackgate capacitors around the op-amps ( I managed to found a couple of good old Blackgate F caps 470uf/25V from ebay. Checks with my ESR meter show that they were perfect. )

Here a picture of the already installed Blackgate capacitors and the AC line RFI filter

3) Change all Oscons with Sanyo Oscon SEPCs
4) Change all other capacitors in digital with tantalum caps

At the end the result was very suprising.
I was not sure if there will be any different with the already moded player. But definitly all of these improvement changed the sound in a more natural and pure way.

If you wonder whether to use an AC RFI filter for the power line - please don't! Just install one and you will hear the difference. No more parasite sounds/echoes, no more "Please stop the music, because it drives me a headache after an hour of listening". It really removes all (or at least most) of those noises that the 220V/50Hz catches on its way from the electric company's power stations to our cd player.