Reply from Beyerdynamic
Hello Mr. Seaman,
thank you for your email! We offer a very nice headphone amp named A 1 http://europe.beyerdynamic.com/shop/hah/headphones-and-headsets/at-home/headphones-amps/a-1-220-240-v.html
and will soon show the new A 20 http://europe.beyerdynamic.com/shop/hah/headphones-and-headsets/at-home/headphones-amps/a-20.html.
So if you want a beyerdynamic amplifier to drive your phones, this is no problem! But you don´t need one necessarily. Any headphone output can drive a 600 ohms headphone, the question is: does it supply enough voltage to drive it loud enough. Apart from “loud enough” being a very subjective factor, it really depends on the voltage, the headphone output is capable to deliver and there is no international standard for minimal requirements.
In general, many battery- or wall-wart powered units work with lower internal voltages (which also may limit their output voltage) as gear with an internal power supply, but as always, this is just a rule of thump. You can power your studio monitors with a 3W triode tube amplifier, a massive Bryston or Crown Reference (or whatever) amp or a regular hifi-stereo amplifier: all three will work, but propably differently.
To our ears, the 250 ohms headphone models are the best compromise between achievable level with “most” headphone outputs and detailed sound. Due to their thinner wire for the voice coil (and therefore lower moving mass), the 600 ohms model sounds even more detailed but may eventually play less loud than the lower impedance version on several “regular” headphone outputs. For maximum level, regardless of the impedance, you will need a dedicated headphone amplifier. Either built-in into a monitor controller / interface or as an external unit like A 1, A 20 and several other amps from other manufacturers.
Kind regards,
Klaus Kirchhöfer
beyerdynamic GmbH & Co. KG