Looking to this 300B amplifier built, it was designed with similar philosophy of Luxman MQ-300. The driver stage is 6SN7 tubes configured in parallel for higher current output, lower impedance and distortion. Instead the original Luxman MQ-300 using total 2-stages amplification in the driver stages, I only use a single stages. The reason for this is because the limitation in the chassis spaces.
The sound quality for this 300B amplifier using a single stages 6SN7 in parallel is actually meet my expectation, but the gain is quite low. My listening loudness is around 55 to 70 dB maximum, not too loud, and the volume level position around 12 to 3 o'clock for 3-volt output from the source. This might be an issue for someone who looking for the gain, but for me this is still acceptable.
The main issue for this amplifier is actually with the sound quality depend with the source level output. I am using my own built DAC or few commercially available source and not all of them can produce 3-volt output. Normally around 2 volt or less. This is become an issue for low gain amplifier like this because low voltage input shrinks the sound-stage and limiting the dynamic. So, my choice for using different kind of source become very limited. On the others words, this amplifier is picky to the source level input.
In this post, I redesign the driver stage and also few clean up the cables inside this amplifier.
