Updates on the Pleiades 2 K117 (2 jfet only) no feedback low noise microphone preamplifier with balanced input and output, 9 volt battery supply

At your risk. It can directly drive 300 ohm Sennheiser headphones by being fed with a shure SM58 microphone from a soft singing voice 24in from microphone. The schematic is as simple as it may get, input transformer, K117 resistance capacitance coupled stage in class A, attenuating potentiometer, K117 transformer coupled output stage! The gain is dramaticaly inscreased by changing the second stage source (bias( resistor to 420 ohms thereby increasing output stage power. 2 tiny (input and output) transformers are used which have a low inductance typicaly 100mH to 4H to cut bass heaviness to listener brain when a flat mic is used in order to compensated for equal loudness curves, voice effort curves. In detail component values, schematic: Mic input transformer: Thordarson MIT 209. 68nF coupling capacitor to gate. !Mohm gate resistor to ground. K117 JFEt. 100Kohm drain resistor (electron tube similarity for high gain , small device current can give very low noise). 10Kohm source bias resistor in parallel with 47uF/35V electrolytic capacitor. 470nF coupling capacitor from drain to 220Kohm log potentiometer. Other side of pot to ground, tap of pot to 2nd k117 JFET gate. 1 Mohm resistor from gate to ground. 420ohm resistor from source to ground for self bias, in parallel with 47uF/35V electrolytic capacitor. UTC DO-T9 output capacitor directly connected to drain as on class A single ended power amplifiers. That's all folks! It is intended to be placed insisde a beautiful looking beige-brown Retex made in Spain console box with a bulgin 9 volt battery holder.