Philips CD650 NOS mods - switchable between NOS and SAA2770 OS

Hi There,

I built a daughter board circuit that sits at the current location of SAA2770 of my Philips CD650. With it I can switch between NOS and OS mode by flipping a switch. There's no circuit modification. You can convert it back to the original hardware configuration simply by removing the daughter-board and re-inserting the SAA2770 back to its own socket.

The daughter board:
CD650-NOS-control-daughter-board-shrinked.jpg


System running together:

CD650-NOS-mode-running-shrinked.jpg


Front Panel NOS indicator:
front-panel-NOS-indicator-shrinked.jpg


Mode control switch and NOS indicator wiring:
CD650-NOS-completed-01.jpg


With the quick A/B listening test results, I prefer the NOS sound. It is more transparent and musical. But it's more susceptible to disc scratches as it's missing the SAA2770 interpolation to cover up the missing data.

A3K
 

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