Is this kind of PSU normal in a CD player?

Bricolo · 30th April 2004, 05:02 PM

That's how my CD player's PSU is
The transformer has only one secondary winding, with multiple voltages. So the current of the +-15V (analog) is shared with the digital ones, and the opposite too.

jean-paul · 1st May 2004, 08:42 AM

Unfortunately this is standard practice with some brands, you'll probably see the benefits of separate windings now.

In this case adding a small transformer can do wonders.

Bricolo · 1st May 2004, 01:34 PM

Unfortunately, those Philips/Marantz transformers are only a part number, no other info on that.
So I have no idea about the VA rating I should use as a replacement

Is there a way to calculate the VA? Maybe with the winding's resistance...

Andypairo · 1st May 2004, 01:37 PM

You can compare the size with other transformers of known rating for example... my CD player's trafo is surely no more than 30VA...so...oversizing your replacement trafo a little won't be that hard (nor particularly expensive)

Cheers

Andrea

Bricolo · 1st May 2004, 03:58 PM

What would you say? 30VA too?

I had another idea that xhanging the transformer: using a second one only for the analog PS (+-15V)
So the "2nd wires from gound" on the secondarie would be unused on the first transformer. Or is the VFT power supply more harmfull for the digital that the digital is for the analog?

Fin · 4th May 2004, 02:48 AM

Hi Bricolo

The power supply in your CDP (CD62???) looks the same as that used in my CD624.

From what I can tell, the +/-15V only supplies the output opamps and there is a -15V going to the Kill circuit.

The +/-5V supply feeds all of the other ICs including the decoder and dac.

The +/-10V supply feeds the servos.

I have thought of adding a new 25-30VA transformer to supply the +/-15V for the opamps and the +5V for the DAC/filter and decoder.

The original +/-15V supply could then be used as a pre reg for the main -/+5V supply, with the added benefit of moving the +/-5V supply further away from the +/-10V servo supply.

I haven't tried any of this yet, but I think it is possible and might be worthwhile.

Fin · 8th June 2004, 07:50 AM

Bricolo

Have you had any progress here?

Bricolo · 8th June 2004, 02:08 PM

nope, I haven't worked on the PSU now.
I'm trying to have Rudolf's super pair I/V working

Fin · 9th June 2004, 12:03 AM

I'm busy collecting info on it now - so when you get there, let me know.

1st May 2004, 08:42 AM	#2
jean-paul diyAudio Moderator Emeritus Join Date: Sep 2002 Location: The Netherlands	Unfortunately this is standard practice with some brands, you'll probably see the benefits of separate windings now. In this case adding a small transformer can do wonders. __________________ It's only audio

4th May 2004, 02:48 AM	#6
Fin diyAudio Member Join Date: Dec 2003 Location: -	Similar layout - similar idea! Hi Bricolo The power supply in your CDP (CD62???) looks the same as that used in my CD624. From what I can tell, the +/-15V only supplies the output opamps and there is a -15V going to the Kill circuit. The +/-5V supply feeds all of the other ICs including the decoder and dac. The +/-10V supply feeds the servos. I have thought of adding a new 25-30VA transformer to supply the +/-15V for the opamps and the +5V for the DAC/filter and decoder. The original +/-15V supply could then be used as a pre reg for the main -/+5V supply, with the added benefit of moving the +/-5V supply further away from the +/-10V servo supply. I haven't tried any of this yet, but I think it is possible and might be worthwhile. __________________ Regards Fin

8th June 2004, 07:50 AM	#7
Fin diyAudio Member Join Date: Dec 2003 Location: -	Bricolo Have you had any progress here? __________________ Regards Fin

9th June 2004, 12:03 AM	#9
Fin diyAudio Member Join Date: Dec 2003 Location: -	I'm busy collecting info on it now - so when you get there, let me know. __________________ Regards Fin

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1st May 2004, 01:34 PM	#3
Bricolo diyAudio Member Join Date: Nov 2002 Location: Grenoble, FR	Unfortunately, those Philips/Marantz transformers are only a part number, no other info on that. So I have no idea about the VA rating I should use as a replacement Is there a way to calculate the VA? Maybe with the winding's resistance...

1st May 2004, 01:37 PM	#4
Andypairo diyAudio Member Join Date: Sep 2002 Location: near Milano , Italy	You can compare the size with other transformers of known rating for example... my CD player's trafo is surely no more than 30VA...so...oversizing your replacement trafo a little won't be that hard (nor particularly expensive) Cheers Andrea

8th June 2004, 02:08 PM	#8
Bricolo diyAudio Member Join Date: Nov 2002 Location: Grenoble, FR	nope, I haven't worked on the PSU now. I'm trying to have Rudolf's super pair I/V working

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