Marantz CD50

[soulminer]

Hi Colin.

Thanks for the post. My CD50 is not a Special Edition, and as such, the PSU is fitted with pretty plain Nichicon electrolytic caps. I would have liked the SE as it would have saved me some time and money upgrading the caps, but hey, it gives me the chance to pop some Black Gates or Silmics or likewise in there.

I like the idea of ditching the op-amps myself at some point and maybe building a valve stage for it, as advertised in Audiognome's Sony post. A project for a rainy day (or week) I think.

The diodes are quite cheap and only took me an hour and a half to fit all ten, so probably worthwhile for you to do that too Colin. I am wondering if there is much mileage in changing/upgrading the voltage regulators too. Something else to think about I guess. A machine is only as good as its power supply after all is said and done.

I may do some case damping myself this week.

Cheers,

[pre65]

Hi-if one is using an external DAC with ones CD player how important would any of the mods you have tried be ?

I presume that apart from the power supply mods everything else is internal signal processing.


Philip

[soulminer]

Hi Philip.

All of the mods I have carried out so far (apart from the PSU diodes) have been on the decoder/filter/DAC section of my player. I am guessing that an external DAC will have a DAC chip and output stages, possibly along with its own PSU too, that could all be tweaked. Op-amps will be in the external DAC too. They can be swapped. Even external DACs will be made down to a level, so there will always be something to tweak inside I suppose.

I think it is just a case of finding out what chips your transport and DAC use, finding the data-sheets for them, studying them and having a play. As always, cleaning up the power supplies using better diodes, caps, inductors, regulators, etc should always help matters. A commercial machine will always be built down to a level I suppose. It is a case of experimenting and doing some research to see if anyone else has fiddled with a player the same as yours before, and what they did.

Cheers,

[colin.hepburn]

Hi Lee
I think I will change the psu diodes and the out put caps I take it that the value for this is about 10uf plus change the op amp I see you seem to rate the AD826 do you have the order code for then I think I will leave the dac side alone I don’t know much about that plus the 52 SE is well tweaked as standard anyway

PS i an a bit concerned about Dee soldering the parts can advice me on this i guess that the Dee soldering brad is the best way to go

[soulminer]

Hi Colin.

I have some spare Burr-Brown chips if you fancy giving them a try before the Analogue Devices. One man's meat and all that, plus if they are not being fed by a TDA1541A output you may find some instability or oscillation. I think Rich found that with his Pioneer. PM me your address if you fancy a go of the Burr-Brown OPAs, but the AD826 RS order code is 522-8130.

The best thing is to remove the original op-amp chips and replace with the small 8 pin DIL holders available from Maplin (FZ45Y). Then you can just pull chips out and push them back in to try them.

On de-soldering, yes I use solder wick or de-soldering braid. I don't like solder suckers personally. I have used all sorts and the only one I like are the big Pace de-soldering stations, but they cost a fortune.

The trick to soldering or de-soldering ICs (or anything really) is to make sure your iron is powerful enough (mine is a 45w 12v Weller with temperature selection via numbered tips - I use number 7). This will melt the solder in an instant and means you don't have to hold the iron on things for long periods of time, which is what causes the damage.

Put the solder braid onto the top of each pad, put the tip of the iron over the top and you will see the braid turn silver with the solder. This should pull all of the solder out. Wiggle the leg of the chip with a pair of needle nose pliers and if it is loose, job done. If not go back with the braid and repeat. Once all legs are de-soldered, the chip will just fall out.

Try and observe ESSD handling precautions with DACs, Filters, Controllers and op-amps. They are sensitive although I have never damaged one by normal handling.

Hope that helps and apologies if I am teaching your grandmother to suck eggs.

Cheers,

[colin.hepburn]

Hi Lee
Thanks for the offer of the IC but I will hold of for the timer beening
I cant seen to use the Dee solder suckers ether I have a 25 and 60 watt Weller with round tip not sure of the size thou… I have dun some Dee soldering but I am nervie of lifting the tracks when I do this bite the bullet and just do it I supposes
Thanks Lee

[soulminer]

Originally Posted by colin.hepburn

I am nervie of lifting the tracks when I do this

Hi Colin.

Again, this is a by-product of having not enough heat to melt the solder quickly enough, held on the pad/track for a long enough period to melt the adhesive that holds the conductors to the PCB. The RS number of the tip I use for general soldering (including ICs but not SMD) is 661-469, which is an F7 1.6 x 1.2 spade. The trick is to get in, melt and wick the solder and get out within, say, 3 or 4 seconds maximum. ICs start to complain if they are heated for much longer than that. This is the advantage of using the chip holders. Solder in once and forget.

Good luck if you decide to try, and let me know if you fancy borrowing the BB chips to try.

Cheers,

[colin.hepburn]

Hi Lee
Thanks for the order codes
I have to Finnish my hard wired Phono 11 and get my turntable up and running First so the CD played is in the list of to-do’s I have some old TV circuits in my grave yard box of bits I can practice Dee soldering on first a good idea I think
Thanks again on the offer on the Op amp I may take you up on that
PS I have some info on the Psu Regs some where if I can find it in the loft I will PM but don’t hold you breathe I Think the faster Regs are the LT7805AT /LT7815AT I think will check on that
Thanks
Colin

[colin.hepburn]

Hi All
For all those that have a CD player with a CDM4/CDM9 transport I.E marantz CD50/52 or other and are looking for a replacement CD drawer gearwheel as it will fail after time a common problem with marantz players I have just ordered one from here http://www.octave-electronics.com/parts.shtml

[colin.hepburn]

Hi All
Well I have reserved my new gearwheel for the marantz CD52 SE today so will fit it to night and hopefully get the drawer working again it I recommended that you use a grease on the wheel can anyone recommend a good type to use on plastic wheel was posted on the 13 th 8 days from Malaysia. not bad service
http://www.octave-electronics.com/parts.shtml