How do i do simple mods to a CDM1 MKII based transport?

[bryanj]

I posted above regarding my experiences with a slightly modified marantz CD75 MKII SE (made in Belgium) containing TDA1541.

I have a non os dac based on 1541 double crown and 6c45pi tubes and am planning on putting the affordable kwak clock on the mechanism.

I have been using this solely as a transport and have discarded the plastic chassis it came in which i replaced with about 6inches of mdf.

I am very much a novice with regard to the electronics side of things and this mechanism as a transport is becoming so good i want to do further work on it to get closer to maximising its potential.

I would like ideally to have the mechanism itself on its own wooden chassis, with all the power supply and other circuitry on another chassis near it. The umbilical cord between the mechanism and the board is only a couple of inches long. It looks like a thin, wide, brown plastic material with various traces running along it. Can i simply replace this with corresponding lengths of cat 5 wire or similar or is there another way of lengthening this cord?

What basic power supply mods can i do? Should i change the diodes for new ones? Can i increase the value and replace the caps on the power supply?

I read that the transformer on Marantz players are not very good. Are there any brands that someone would recommend?

Lastly i have been trying to find out if this mechanism can be converted to I2S but have not been able to find out via diyaudio whether this is possible. Some posts seem to suggest yes and then others say that its only possible on the CDM4 mechanism on.

Thanks very much for any replies and for an awesome forum which makes DIY so much more enjoyable than just buying new stuff.

 

[bryanj]

Anyone? Or has this topic been done to death somewhere else on this forum? Ive spent a few hours looking through things but nothing seemed to show up. I'm new to this forum and this was my first post and was hoping for some advice as to the direction i should take.

 

[zygibajt]

I am very much a novice with regard to the electronics side of things and this mechanism as a transport is becoming so good i want to do further work on it to get closer to maximising its potential.

I would first disconnect all the chips you don't need any more (op-amps, DAC chip) from inside the player.
Change all electrolitics to better and new ones for sure. Leave the orginal values. You can try some better diodes like MSR860 or BYV26C. Also original output transformer is of very low quality, I would exchange it for decent one. You can put BNC digital connector, too.

The umbilical cord between the mechanism and the board is only a couple of inches long. It looks like a thin, wide, brown plastic material with various traces running along it. Can i simply replace this with corresponding lengths of cat 5 wire or similar or is there another way of lengthening this cord?

Sure you can If you do it carefully. I'm afraid CAT 5 cable might be too stiff and too thick, you will probably need thinner and more flexible wire, multistrand might be better. Also it would be good idea to take the white mounting for the umbilical cord out of the orginal PCB, mount it underneath the transport and run the wires from that point to the PCB and use orginal cord which might work better. I think it would be good idea to get rid of the orginal plastic mounting the alu chassis of CDM1 MKII and mount this alu chassis directly to your wooden chassis with orginal spring. You can also use it as top loader and make some heavier than orginal clamp for the disc.

Lastly i have been trying to find out if this mechanism can be converted to I2S but have not been able to find out via diyaudio whether this is possible. Some posts seem to suggest yes and then others say that its only possible on the CDM4 mechanism on

I think I2S is a matter of the DAC and reciver , not the transport. CDM4 is pretty much the same as CDM1 MKII. The diffrances are CDM 1 has alu chassis and brushless motor, arm and lens are the same.

That is what I think , but I'm not a big expert at this.

Bartek

 

[bryanj]

Thanks very much Bartek. You've given me heaps of great ideas to try. this will keep me busy for the next litle while. Thanks again and i'll post my results when its done.

 

[Searcher]

Hi I commented your earlier thread( pleas check it)

And secondly as I have the same player and same experiences with the transport I would like to know more about yor dac.

regards
Peter

 

[Lourens]

more ideas

Although it is in Dutch, you can get some more ideas from this site from a friend of mine, about modding another cdm1 mkII based transport. We both experienced pretty much the same stunning results as you described (in your other post) against many very well respected transports.
Don't forget to put a clock upgrade on your to do list With a Tent XO3 you also get a very good new spdif output. Very important!

Good luck, and do not hesitate to ask/mail if you encounter translation problems.....

Lourens