My AKG HEARO 999 transmitter base has a jack for wired headphones. It is perfect with my AKG K601 headphones. No surprise there, it was a pro level tool for engineers. If you use DT880 headphones, the recessed midrange becomes more recessed. With midrange forward AKG headphones, the midrange is just about perfect and the K601 headphones become very well balanced across the entire frequency range. It has very good drive capability, because many AKG pro headphones are somewhat hard to drive. The entire setup was $650 for the setup with two headsets, and the aluminum carrying case. A pro unit all the way, and the transmitter base is also an excellent DAC and a nice little preamp with its variable output. The adjustability of the sound, synthesized reverberant soundfields, surround sound, and all, are far beyond what comes on higher priced "audiophile" headamps that have far less real engineering and do far less. I use the DAC in the transmitter base instead of the one in my SACD player because it is better. The HEARO 999 flew under the radar of most headphone nuts, but then again, it was mainly made for sound engineers.
