I have been into headphones for many years and owned many different headphones and dedicated headphone amps. I also happen to own the Pioneer A35R and the Senn 280 Pro's.
The headphone out on the Pioneer is dreadful. You may not think so, but if you've ever heard a decent HP amp, you would. The Senn 280's are not difficult to drive, but have a limited upside as to what they can deliver.
I would suggest you pick up a used Senn 580 or 600, and a modest tube amp, such as a Little Dot or Antique Sound Lab to get a taste of what headphone listening can really offer. To learn more, check out Head-fi.org. And... sorry about your wallet.
The headphone out on the Pioneer is dreadful. You may not think so, but if you've ever heard a decent HP amp, you would. The Senn 280's are not difficult to drive, but have a limited upside as to what they can deliver.
I would suggest you pick up a used Senn 580 or 600, and a modest tube amp, such as a Little Dot or Antique Sound Lab to get a taste of what headphone listening can really offer. To learn more, check out Head-fi.org. And... sorry about your wallet.