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Cambridge 640C Mods

Cambridge Azur 640C (ver 1) CD player


Back in March 2007, I bought a Cambridge Azur 640C (ver 1) CD player from Richer Sounds.

The version 1 units have gone 'end of line' now, so it was a bargain at £149. Although I see that just recently (July 2007), they have been advertised as low as £99.95.
In any case, my unit suffered from the standard problem, that being a noisy mains transformer.
Rather than go to all the touble of returning the unit (and probably getting another faulty one) I decided to risk my warranty, and modify it. I removed the original Cambridge transformer (a standard 'e' core lurking underneath a so called 'copper' disk, made to look like a toroidal transformer.
I fitted two toroidal transformes in it's place, with the added bonus of providing two seperate supplies for the DAC and the servo / clock circuitry. This did bring about a noticeable improvement in the sound quality, and the speed of the mechanism seemed to improve noticeably as well. I measured the current drawn during play / seek operations, and the servo circuitry consumed quite a lot more current than expected, at around 200ma in 'Play' mode, and 900ma during seeks. (I'm quoting these from memory, so I could be wrong!).
The DC supply for the servo circuitry looks as though it would benefit from some modifications, but until I can get a schematic for the unit, I'm reluctant to perform any further modifications.
I was surprised to see good old NE5532 opamps in the audio output stages!

Front view of player

Cambridge Azur 640c

Top view with new transformers fitted.

Top view of new transformer #1

Top view of new transformers #2

top view

Close up view of transformers.

Close up view of transformers