Doubling the loudness of the Pleiades 2N3053 single transistor minimum negative feedback audio power amplifier

Audio transformers are amazing sounding fantastic creatures. Collector to base single biasing resistor changed from 100KOhms to 200KOhms. Sound is much more open, bigger, deep with more detail, louder. Collector current is just 5mA, am I dreaming? It makes sense since supply voltage is 12V, therefore Vb:Ic=12V:5mA=2.4KOhms, the output transformer is 2.5KOhm to 8 Ohms so impedance is matched, hence no energy reflected back from the speaker to the transistor. Signal path: Time - Alan Parsons Project - Sony CD Walkman 300ohms line out - Pleiades 2N3053 with Sowter SK05s - KEF CS5 constructor series (tweeter connected in phase since the day before yesterday!)

On making quick changes on experimental circuits

At your risk. Without using a soldering iron or screw driver for barrier strips or springs or aligator clip cables, the Wago instant snap barrier strips can be used. For example in connecting the Sowter output transformer SK05s to the Pleiades 2N3053 single transistor power amplifier and the speaker, (2.5Kohm to 8 Ohm impedance trnsformation ratio).

Pleiades single 2N3053 class A audio power amplifier with Sowter SK05s output transformer

At your risk. Feel so happy. Rediscovering the merits of larger speakers. Thank you Vicky for pointing out how good single transistor amplifiers sound. When including the output transformer the bass is huge, deep, jaw dropping even at 1/10 of a watt output. Schematic similar to Pleiades 2N3055. Bias with a 95K from collector to base. Signal path: Time - Alan Parsons Project - Sony CD Walkman line out - Pleiades 2N3053 with SK05s output transformer - Marantz Imperial 5G or KEF CS5 or Philips FWB-C155D/00. Operating conditions: Vb=12V , Ic= just 12mA. Smooth dreamy sound.