The Philips CD304 is identical with the Grundig CD 7550 and originates from the same Generation of CD players, such as the CD104 and CD204, what are the parts of either the Chassis with the power supply or the Servo and transformers circuit boards with the CD304.
In contrast to the original CD304, the successor CD304 MKII has a TDA1541 converter with 16 bit resolution. In addition to minor details, the main difference between the CD304 and the CD304 MKII lies in the completely changed converter board.
The CD304 and the other models of this generation are still among the best models ever built in terms of their workmanship and sound. In particular, they are excellently suited as a basis for modifications.
The 7550 from Grundig has no FB, no headphone/ adjustable output!!, but is better in terms of sound - I suspect the Grundig engineers have once again taken time for a tuning! HW