With modern low-noise transistors, you can build an MC step-up with only one transistor.
The MC step-up is powered by a 12V lead-acid battery. The value of R4 depends on the hfe of the transistor used.
Transistor--R4 -- hfe -- Relative Noise for transistor
The brand of the transistor is very important. I found that Philips MPSA 42 and Philips BC 639 are 5-10dB more noisy than Motorola. Distortion of the amplifier is low due to local feedback. The gain of the amplifier is 19-20dB. If you have a problem with radio frequency interference, place a 22nH inductance in series with C1 and a 22pF capacitor in parallel with R4.
COMPONENTS:
- C1 2.2uF polypropylene
- C2, C3 1uF polypropylene
- R1. R2 120-ohm wirewound
- R3 1200-ohm
Above: Fig. 1: Step-up circuit.
Above: Fig. 2: Pinouts for different transistors, bottom view.