For a couple of years, my main CD source has been my Theta Data Universal Transport — a laserdisk/CD player from the early 90s. Fed through a Meridian 518 for dejittering and upsampling to 24-bit, it has always sounded good through my Yamaha DSP-AX1 amp. But recently, I’ve started to feel it’s been missing something at the top end. Conversely, CDs played on my Arcam FMJ DV27 have sounded mechanical, with a lack of warmth in the bass, and overbright, unrefined treble. Assuming that the Theta’s failings at the top were probably simply masking the limitations of the Yamaha’s power …