It is a low power amp and for some reason they artificially limited it's power output more than they had too. They said they didn't want to get blamed for damaging people's headphones but I don't know why they would have issues with that when no one else worries about it. It does sound very nice though. I admit that when listening to classical with LCD-2's I can get to 100% volume. It's loud but not crazy loud and obviously that's not an issue with Rock and some other music. This however is a very different and unique amp design which makes the being at 100% irrelevant (unless you just need it to be louder). But the amp operates at it's optimal gain 100% percent of the time no matter what you're listening to and what the volume is set at. Always. The only thing that changes is the output from the DAC. So there is no way to overdrive the amp and it's always ''in the sweet spot''. The DAC uses all 32 bits of the Saber32 for volume control so there is no loss in SQ or compression when using the digital volume.
The DAC is great and the USB DAC, unlike other USB DACs that I've used, simply works and works well and I've never had to mess with it and never had to screw with settings to make it work. I sold my $1032 Audio-gd Ref-32 after I got the 105. I'm not saying it's better or that anyone else will get the same results but I like it and it helped me simplify my system.
Even though I've been using the 105 as a preamp for the last several weeks I haven't actually compared it until this weekend. Comparing the oppo directly to my emo XPA power amp over XLR and the oppo thru HDMI to my Marantz AVR and RCA to the XPA produces a very very very large and unmistakable difference. Granted my AVR is fairly low end but I picked it because I only have 1 input to it so though I had more money to spend I didn't see the point in it. But you don't have to even be looking for a difference let alone doing some real critical listening (in my system) to hear a vast improvement in going directly from the OPPO to my power amp. It's like getting upgraded speakers. You may not hear a difference if you have a d2v or similar but I'm willing to bet most people will hear an improvement by skipping the pre/pro.
Thanks for the useful information! It's too bad that after going to all the trouble of putting a headphone amp into it, Oppo then decided to gimp it's power output. With only 34mW going into 300 Ohms, I'm starting to think I would still end up needing a separate amp for my Senn. HD650s.