This is a preamp\headphone driver using a single 2N3055. An electronic friend of mine said that many times large power transistor are quieter than smaller transistors due to their large base. I took his advice and made this emitter follower preamp\headphone amp. You lose about 10% of the signal because of the emitter follower but it drives really well into low impedance loads. It drives my ATH700 Airs (33ohm 98db efficient) with ease and is dead quiet. Strange build with the 2N3055 bolted to a block of Merboo timber for resonance control. I call the preamp "Woody Pro".
Built in an attractive 19" 1U rack enclosure with a 4oz solid brass knob. The construction is dual mono starting with the PS. The PS uses potted mini toroids then two stages of 10,000uf Nichicon caps for a total of 40,000uf of filtering. The PS uses discrete ultra fast diodes and like the large filter caps these are individually snubbed. The whole PS is layered in bitumanised heavy Al foil for shielding and resonance control. There are two separate PSs. The output caps are 10 X 10uf polypropylene to make up the 100uf required. There are two banks of these output caps for a total of 20 caps. The output caps are also snubbed.
The internal audio wiring is 0.7mm five nines pure silver and power connection via OFC. Frequency -3db points are 10Hz to 135KHz.There are two switchable inputs both RCAs with one RCA is also connected to a 6.5mm phone jack. The output RCAs are also connected to 6.5mm phone jack. This is so the preamp can be used as a preamp and\or a headphone amp. Great sound, absolutely dead silent and excellent dynamics.