Originally Posted by The Fed
That is the one thing that has me hung up.... The picture shows a relatively well evolved headphone out circuit so they thought about it...but integrated amp/ receiver manufacturers rarely (if ever) spec out their headphone amp and output.... So output impedance and RMS output are two specs that are vital but will be virtually impossible to find.
I have (2) lower impedance planar magnetic headphones that require a lot of current but are low voltage so synergy with a big voltage monster like this is a big questions mark.
May check locally to see if there is one on the shelf somewhere and see if I can plug in with my Hifiman or Audeze to see how they sound.
If I was running Sennheiser 650's or Beyer 880s like yourself.... It'd be a no brainer.... I am in, but these planar cans are testy little buggers..... I'm sure it could/ would make them loud, but would there be damping problems with impedance interplay.... Loud but degraded is not ideal.... I need to dig a little more to see what I can find out.
I don't think there's a separate headphone circuit on this amp. Also, I don't know why people have this misconception that headphone outputs on amplifiers are an afterthought. They really aren't. Sure there aren't separate circuit boards for headphones on most amps, but after hearing many of them, I cannot agree to that at all. Manufacturers indeed pay much attention to the headphone outputs performance , as much as they do for speaker outputs, because at the end of the day, a headphone output should have exactly the same sound signature and quality as the speaker output. Thats the goal, to make the amplifier work well for all the purposes its built for, and the reason why there's a 6.3mm gold plated headphone jack on the front is not to make the front panel look nicer, its to plug in high quality headphones.
On Onkyo, the headphone output is fed from the same circuit from which the speakers are fed, same as on any other integrated amp, except here its all digital. I don't know much about it technically, its really a unique design, but the bottom line is, its fed from the same "source" as the speakers, but the output level is digitally controlled, unlike on normal integrated amps, where the output is "physically" controlled by adding resistors between the power source and the headphone output. That results in slightly lower output impedance. Around 50 ohms, compared to 100-200 ohms on other amps. But I repeat again, ALL integrated amps I've tried sounded excellent with my DT880's and absolutely none of them were in any way inferior to dedicated head amps I directly compared them with, in fact, all of them were superior in terms of output power and authority, as well as having a bigger soundstage.
IMHO, in my mind, after conducting the tests, dedicated headphone amps are a waste of money. There I said it. Overpriced quite simply. Unnecessary, UNLESS you really have some crazy hard to run high end headphone, or no other place to plug your headphones, like a integrated amp, receiver, even a CD player or a higher end TV. Heck, the headphone output on my Panasonic plasma (a pretty high end model though) TV sounds freaking amazing and runs the DT880's better than any of those dac/amps deviced I've tested. It sounds excellent with low impedance Ultrasone Hfi-2400's as well. I'd really like to see the face of a hard core audiophile when hearing how the Ultrasones sounds fed directly from the Panasonic TV playing something like Eric Claptons Unplugged album. Just stunning.
As for dedicated amps, you pay loads of money for a little piece of circuit board thats worth, lets face it, 50$ tops even in 500$ head amps, you usually get poor build quality, and you get performance that you would get from much cheaper, much more all-around devices, aka. receivers or integrated amps. Even with low impedance cans, its no big deal. Some people on this forum use D7000's with higher end integrated amps and say it sounds better than with any headphone amp they've heard so.... I already sold my Bellari tube amp. Its really rubbish compared to Onkyo, or even the Panasonic plasma. Really people, if you have any higher end device at home that has a headphone output, try it before buying a separate amp.
Edited by derbigpr - 8/17/12 at 3:25pm