Millett "Starving Student" Hybrid headphone amplifier
This is the MSSH I built using point to point wiring. I designed a 48v linear regulated for the amplifier, mainly because I already had a transformer with the right secondary voltage. The original enclosure was hand machined out of clear plastic sheets I had laying around. This proved a bad choice, for many reasons. First, the plastic offered no resistance to electro-magnetic interference, which made the amplifier pick up all sort of bad noises. Second, PMMA is a brittle and chemically unstable material, and it shattered under stress when in contact with solvents (used to clean the flux). Third, plastic is a thermal insulator, and melts at relatively low temperatures. This makes it a bad choice for this amplifier, as the 0.3A of bias current drops many watts across the circuit. The original enclosure also suffered from a less than optimal format, which took too much space and was awkward to work with. I promptly decided to rebuild the amplifier in an extruded aluminum enclosure, namely the Hammond 1455T2201. After machining it and painting it, I must admit it looks much better than the original design.