Got some new headphones last week, Sennheiser HD 570, open-air mid-fi quality. It has been a long time since I had headphones (other than cheapo lightweight portables), so of course I spent some time playing with them. Depending on which jack I plugged into, of the 3 available (see below), the sound was quite different.

  • Sony CD player model ??, bought in 1991 or 92.
  • Denon AVR 2800 Home theater receiver, purchased in 2000
  • Sony DVD player, DVP 530D, purchased in 2000. It also has a volume knob for the headphone jack.

While listening to CDs over the headphones, the CD player sounded noticeably better than the HT receiver. The sound from the CD player was clear and open, while the sound from the HT receiver was muddy and more compressed. Surprisingly, the sound from the DVD player was also inferior to that from the CD player. I made an effort to adjust the volume so that they seemed the same for each plug-in point, although I could not measure the volume in any objective way.

I canít remember the model number of the CD player. If its important, I can find out tonight. It was the least expensive single play Sony model available in 1991 or 1992 that had remotely controlled volume. If memory serves, I paid $200 for it. It has a mechanical volume knob that turns via an electric motor when you adjust the volume with the remote. It looks cool, but I can't say whether it provides an audio benefit. It has two sets of audio out RCA jacks. On one the volume can be varied, and on the other the volume is fixed. The same knob varies the volume available at the headphone jack.

The DVD player has only been used via a digital connection to the HT receiver, so I have never listened to its internal DAC before. When I listen to CDs over my loudspeakers, I have never noticed such a large difference between the CD player and the DVD player. I have read that the DAC chips on most DVD players donít perform well because the manufacturers guessed that they would only be used through TV sets. Most owners of better sound systems send the digital signal to their HT receiver. That may be the case for my DVD player.

But why is the sound so much better at the CD player headphone jack than at the HT receiver headphone jack? Any opinions?