My next project..

[Richard Nichola]

..is to take a cooking CD player (I've got a Cambridge CD4,Dac magic and a Marantz CD50) and spice it up with an external power supply. The reason for doing this rather than a DIY XPS is the resulting bang if I make a mistake will be rather less costly than a CDX sized bang.

I've had a look inside the CD50 and looks a simple sort of project. TDA1541 based. Interestingly, it looks at first glance as though Marantz made a better job of the crystal coupling than they did on the CD63...

Can anyone help me try to locate a service manual for the CD50?

Do any of you have an opinion on which is the best of the three devices to mod?

Any opinions on which is the best cheap multipole connector to use for the voltage rails?

 

[martin clark]

Any opinions on which is the best cheap multipole connector to use for the voltage rails?

Something you can't possibly confuse with an audio connector!

Have a look at the 'D' connectors used for computing peripherals - they're cheap, lockable via thumbscrews and most types are rated at 5amps per pin - not bad at all, really. They're no more fiddly to wire up than any other multipole connector, and can be fully-screened too.

25pins ought to be enough for anyone

 

[ced]

I'm using neutrik speakon connectors which are excellent and not expensive. They come in 4 and 8 pole flavours and can take large multicore cables and easily low impedance 2.5mm cores. The pins are also already fitted and you can screw down and then solder them in. Also the contact resistance is just 3mOhms which is as low as the naim burndys (bantam twinlocks) with turned pins. You have to dig around to get lower.
Farnell 724-567 and 724-579

cheers
Ced

 

[zanash]

Replace the diodes in them all for starters, I think you will be very suprised at how much more the units will give you.

My Diodes of choice would be the schottky 11DQ10 for the cdp and dac.

 

[Richard Nichola]

TDA1541A chips running at 4x oversampling sound better with the oversampler taken out of the circuit. The nature of doing this mod is that it takes the audio output to -3dB at 20Khz, but it also increases the musicality of the player and this sounds like a good thing. (Les does this mod to the AAA5+ and the CD3)

The oversampler SAA7220 puts a lot of noise on the power supply lines and is best taken out of circuit. You can only do this if you fit an superclock type circuit to replace the same circuitry built into the SAA7220. I've got loads of room in the case because I can take out the variable/headphone output board.

Opamps used are the NE5532 (I/V conversion, then filtering) and I guess that these can easily be bettered.

So stage 1 of the mod will be a dedicated A/D supply and a superclock also with dedicated supply.