This amp was one of the last amp Headroom made. I’ve owned this amp for 8 years and the main reason is because it has a op-amp crossfeed circuit. What is does is it take a small amount of signal from one channel, time delays it ever so slightly, and sends it to the opposite channel. The reason is stereo recordings are engineered with 2 speakers in mind. So when the engineer pans the records during the final mix it works great as both ears hear both speakers. That doesn’t happen with headphones. So rock recordings that are heavily panned don’t sound natural. Crossfeed circuits solve this. The downside is mics that are not panned like lead vocals are a little bass heavy. And most classical and any mono recordings don’t benefit at all. That’s when you switch it off. There is a Meier module in Foobar that addresses this. However I find the circuit in the Micro Amp is the best I’ve heard. Plus this little amp has some serious power.(it has an external power supply that I upgraded) However no amps in production have this feature. So an amp I paid $500 for 8 years ago remains in my system. In the early days of stereo engineers became “pan happy” like old Beatles records. When you switch on crossfeed, it’s jaw dropping. I’ve been an audiophile 33 years and I’ll use this little amp until semiconductors fail.
Actually, there are quite a few production headphone amplifiers available that DO have crossfeed, including some very recent, and much more capable, designs. They generally give it a brand-specific name, but it’s there all the same. And several of them have adjustable levels of crossfeed, do a better job of not shifting the tonality of the source material, and yield better results (compared to the Headroom Supreme, Micro and Desktop at least).
Meier Audio has it on all their desktop amps, SPL have it on their Phonitor line and iFi Audio offers at least three units that include it. iFi’s implementation on the Pro iCAN is particularly impressive.
There are plenty of interesting software implementations (and features in combined DAC/amps) that take things further and do an even better/more convincing job - two of note are WavesNX and Out-of-Your-Head.
I love the crossfeed. I love the warmths that the headroom amp has. I like it on all the time. It is my fave thing about the headroom amps!
I wasn’t aware there were so many units besides the Meiers. More to the point is I wanted to convey the importance crossfeed effects can have on headphone listening. I experimented with the Meier module on Foobar, but wasn’t able to achieve any satisfactory results. It’s just easier to flip the switch on my Micro Amp. One thing I always do is listen to most tracks with the circuit on or off and let my ears be the judge. It’s actually surprising how many songs are just fine with no crossfeed. Since binural recordings are practically nonexistent crossfeed can really make a huge improvement. However there are many “purests” who are vehemently opposed to this feature and almost all high-end amp don’t have it. The only option is to use software like JRiver or Foobar. I’m not familiar with Mac software. They are wonderful computers but not cheap. Wish I had one!
Volumio audio player offers a plug-in (Bauer).
I love crossfeed on my Rockbox’d iPod Nano.