Clocking a Marantz CD-94

[FraserSoft]

Hello as this is my first post here bare with me if the same thing is buried somewhere but I couldn't find it. I have recently dug out a Marantz CD-94 from under my bed and decided to do something with it, first thing was of course replacing the belts which is now done. While I had it in bits I thought I would fit the Trichord clock which has been running for many years in my CD-85. I thought I had connected it up correctly but no joy. I got my scope out and counter and confirmed that the clock was working and the frequency is right although the waveform looked pretty awful, so went back to the original clock bits and all is well again.
Has anyone got a simple diagram that shows how to connect an external clock to this CD player, by all accounts the Trichord clock has a good reputation so would like to get it working.
Many Thanks
Alec

[UV101]

Hi Alec.

I've got significant experience with this player and there is plenty you can do make the player very good.

I wrote a document on advanced clocking and other useful info I found here and used over a 2 year period. I ended up with a very good player.

http://www.fidelityaudio.co.uk/1541%...ng_03.2ver.pdf

You will want to change lots of electrolytic power supply and decoupling caps as they will be in poor condition after this time. You will need to change the 5 33uF on the CDM-1 transport to bring that back as it should be.

The biggest single upgrade you will give this player is to provide a decent quality voltage regulator specifically for the 7220 filter chip.

I tried lots including a valve buffer on the output stage.

I have some pics here http://photobucket.com/albums/rr332/Trunky1812/CD960 Mods

Mine was CD960 by Philips but they are identical except your dac is a TDA1541a and mine was the non a. This didn't last long as I swapped it 1st for the a version then for an S2 double crown.

You can learn about the chip grading here

http://www.dutchaudioclassics.nl/Philips-TDA1541/

There is lots about this chip here on the forum as it was used in pretty all the marantz and Philips players around this time.

[UV101]

1 other thing, you'll need to check the loading belts for the mech. If the mech loads ok then fine but there is some incorrect info relating to belts floating around on the net. I followed several recommendations and always got much thinner belts that just were not up to the job. In the end I got suitable 'o' rings which have been fine

[FraserSoft]

Many thanks for the info, I managed to get a set of belts from a guy in Germany and found them to be perfectly okay.I was a service engineer all my life till retiring in 2009 and now having fun getting back into Hi Fi.
Alec

[UV101]

Good progress to start then :-)

I used std Oscon caps to replace the blue Philips caps on the CDM1.

In general, I used Mundorf electrolytics and panasonic fc's for the smothers. In the absence of black gate caps, I use rubicon zlg 470uF for analogue local decoupling and nichicon solid polymer for any digital rails. The analogue regulators are discrete in this player so are reasonable. Opamp wise lme49710 are excellent drop in replacements and you can take the output direct from the 1st set of opamps is you want (see my document for details as you need dc blocking caps unless you null the output ;-) )

Definitely replace those green bit decoupling caps with some film ones around the dac. Also increase the value to 1uf for the msb!!

The cd960 service manual contains the schematics you want, but the 94 service data and cdm1 manual are on my website.

http://www.hifisounds.co.uk/ServiceManuals.html

[FraserSoft]

Hi thanks for all the suggestions, I managed to get the Trichord clock running yesterday and will be doing some listening over the next few weeks. My CD-85 which I used to listen to has the TDA1541A S1 single crown chip in it and had considered swapping it with the standard TDA1541A in the CD-94 but there seems to mixed opinions on how good/different it is. I know it's an old cliche but as a pensioner funds are limited and I do not intend to get involved in the really serious tweaking. I have a slightly cynical view as to what point in all this tweaking do you stop listening to the music and only listen to the electronics. I worked a service engineers in a specialist Hi Fi dealer for over 17 years (Linn, Naim Audio, Musical Fidelity and Meridian) and had the opportunity to experience both.
So one step at a time funds permitting and I still have to rebuild my Musfid Dr T of which I have 3 and when the 3rd one is finished it will be the equivalent of Naims 6 Pack, one psu for each channel using 500va toroidal transformers etc. It's just as well I'm retired or I would never have the time....

[UV101]

The really great thing about those caps (except the mundorfs) is that they are very cheap!!!
The rubycons and inch icons are a little over 50p each from RS or Farnell!!!!

The opamps make a nice difference and can be got from the USA on eBay for less than £3 each delivered!

You are right about the listening but I would say these mods do not loose the character of the player but they do start to sharpen up what by default is fairly wooly. The TDA chip really is very good with a very warm character and really shines with some carefully chosen mods

[FraserSoft]

Would you reckon it would be worth the effort swapping the DAC's over as my CD-85 has the TDA1541A s1 single crown. Getting the DAC out of the CD-94 is easy but it looks like plated through holes in the CD-85. I have changed the op amps for some OPA604AP and looking at the logo they look like Burr Brown chips. At the prices you have given for the cheaper caps that won't be a problem and I do have an account with RS and Farnell so I will look into to that.
Thanks again for your help

[elektroj]

Originally Posted by FraserSoft

Would you reckon it would be worth the effort swapping the DAC's over as my CD-85 has the TDA1541A s1 single crown. Getting the DAC out of the CD-94 is easy but it looks like plated through holes in the CD-85.

It would, if not the pain in the neck with desoldering. To my ears upgraded CD-94 and CD-960 always sounded better than CD-85 or CD-880, no matter what. I had them all on my bench and in numbers. Still using CD-94 myself. Nice machine.
What 1541 do you have in your player? With "A" or without? Try regular "A" version first, before "destroying" your CD-85 - finding it shouldn't be that difficult. And, by the way, swapping SAA7220P/A digital filter for 7220P/B is also big improvement. (PM me if you have problems finding these).

Best,

[FraserSoft]

The one in the CD-94 is the TDA154A and in the CD 85 TDA1541A S1 single crown...