I recall doing most of the listening using headphones, pretty cheap ones as I did not have the budget but still I was fascinated with immersion into the spatial sound field. Things progressed, I got better headphones and a better amplifier, eventually I changed to a digital amplifier as I was experimenting with optical digital sound transmission from my PC. Still, that old feeling of immersion did not return. Sure, the background noise levels were a lot better than with my old Revox A77 tape machine and movie sound effects were amazing. In the old days however, when Radio was still developing, when sound engineers still sat in front of real equipment (as opposed to keyboard and mouse), German radio stations had recordings in so elaborate techniques as "Kunstkopf Stereophonie" in their repertoire, a technology where microphones were placed into the ears of a recording device the shape of a human head, in order to replicate the exactlistening experience a real listener would have had. That's how I fell in love with headphones.
Headphone amplifiers
The stationary rig
After my old Headphones broke up, I could not resist the temptation of buying a Sennheiser HD600 which is a fine open system in conventional (electromagnetic) technology. Not that I would not have liked Electrostats but neither did I like the price tag nor the thought to have several kilovolts of electricity just millimeters away from my ears.
The HD600 sounded nice when used with my amplifier of that time but not nearly where I wanted to have it. So I browsed the internet and ran into a sweet website at www.headwize.com which centers around everything related to headphones. There I found this lovely tube OTL (sans output transformer) amplifier schematic which I modified slightly to match the locally available components. It turns out, Singapore has several shops for tube enthusiasts which stock vast quantities of new and nos tubes as well as all required tools. I used to build radio equipment with tubes in the past so the electronics were somewhat familiar. So I built my first tube headphone amplifier.
I can very well recall trying it for the first time on cheap earplugs (in case something blows) and then on the HD600s, listening to Jamie Cullums "Twentysomething" CD, a lovely recent analog recording. This sound was so completely different from the one experienced previously on the stationary amplifier, very warm in tone, full and rich in bass and thorough in dynamics. A perfect match for the HD600!
The portable headphones
As I travel a lot, mostly on flights of 12 hours or more in length, I had to choose a second, portable rig that allows me to improve the audio situation in that environment. As a headphone, I chose Sennheisers PXC300 noise canceling headphones. Of course Bose offers better noise cancellation as the headset is completely enclosing the ear on top of the electronic noise cancellation. Choosing the right headset for inflight application however is a tradeoff between size, weight and audio performance. The PXC300´s fold nicely into a tiny case which easily finds its place even in economy class (Business class has noise canceling phones anyway). The phones already work nicely stand alone and come with all sorts of adapters that work with most planes.
Some of the cheaper airlines do not yet offer individual inflight entertainment systems so a recent iPod Video with a couple of episodes of your favourite TV series is a Godsend! To complement the Headphone, the iPod and the in-seat entertainment system, a pocket sized solid state amplifier based on Chu Moys legendary design comes in handy.
I had nice PCBs with decent trace width made and built a couple of pocket sized amps with them. Not the same as the stationary rig but really gives the kick when on cruising altitude.
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