Philips CD650 mods

I've only seen that changing these caps value makes the sound different, not better.

Hi Matthieu, you should read here. It explains lots about these caps.

http://www.diyaudio.com/forums/digital-line-level/79452-building-ultimate-nos-dac-using-tda1541a-274.html#post1784706 Link is direct to the MSB caps info

I use Mundorf 1uF MKP's (MSB) and 470 mkps in my philips
I got 1uF OsCon Elcos (MSB) and 220 mkps in my DAC
and I've just got (yet to fit) PPS's as per the link above to try in my Meridian!

TBH, I couldn't tell you which was best! I'm hoping the Meridian! :D

You should hear distortion (bit errors) if you mess the MSB up enough!
 
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and since only -15V is used in TDA as for this analog part

Unfortunately not, both +5V and -5V are also used for analogue circuits, in fact both +5V and -5V appear to be most critical. I had best results with approx. 3000uF (multiple caps in parallel) for power supply decoupling (TDA1541A).


This has been discussed before some time ago. Indeed all are used for analog stuff. -15 and -5 to power (part of) the analog sections inside the chip.

And +5 as the audio currents also go through there (and not through agnd).
 
Hi for everyone,very nice discusion & now at this moment I am confused with what to do,and everything depends on the answers of SimontY & others who did a lot of tweaks for they cdps,so here is a question how much do you spend on tweaks(money) & with who you compare yours cdp and how does it lucks?
p.s. I have some Philips base cdps and dont know what to do-tweaks or look at this like MUST SEE! Parasound D/AC-1100 Ultra Digital-Analog DAC - eBay (item 200445995346 end time Mar-13-10 08:42:57 PST)
thanx a lot.
 
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My ugly duckling
 

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Non os, schottkeys, LM4562s, new caps, clock.

Singing like a bird. Not a lot of space to work with though, I'd like to add some new supplies but I'll amybe use this as a proof of concept and do that with a Mission PCM7000 I picked up recently. That has a very nice display that I can read from across the room.

Pete
 
My ugly duckling 2

Swapped in an A dac.
Added new LM317/337 regs for DAC +5, -5, -15; 7210 +5; clock +5 and opamps +15,-15.
Replaced the dac decoupling with 470,220n film caps.

Sound is very much more detailed now, lot's of seperation on instruments, vocals etc and a much better soundfield.

On the downside it's getting very messy and very fragile inside the case. Don't think there's much more I'm going to do to this one.

On the upside I've got a mission 7000 which seems a very similar build but in a wider case (so more room to do things like place regulators) and one of the nicest (and biggest) displays that I've ever seen.

Pete
 

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They fill up too easily don't they?! Separate regulators for everything are a must.

I've just bought an Arcam Alpha to transfer my mods to. My CD650 has a fault that's too hard to trace, probably a hairline fracture across a track somewhere.

The Arcam Alpha's quite similar inside and looks like it's based on an old Philips board with an added "daughter board" with the DAC and output section on it. It uses two transformers.

Simon