Hi Folks,
I'm not too familiar with germanium transistor circuits, so I have a question about the output impedance of this one...see attached schematic. It is a three transistor circuit with input transformer - only the relevant output stage is shown. Basically, as it sits it will drive a 100k load just fine with 1% THD+N at +7dBm output. Change that load to 600 ohms and the output level drops like a rock, -15dBm or so. Next I tried a 15K:600R transformer on the output, but the max output I got was around -5dBm.
So my questions are:
A) I thought transistors had a low output impedance. Is this not true of early germaniums? Or is the 8k2 resistor responsible for this?
B) If an output transformer won't work, can I make it impedance balanced? Would that require an 8k2 resistor or does the cap change things?
I'm not too familiar with germanium transistor circuits, so I have a question about the output impedance of this one...see attached schematic. It is a three transistor circuit with input transformer - only the relevant output stage is shown. Basically, as it sits it will drive a 100k load just fine with 1% THD+N at +7dBm output. Change that load to 600 ohms and the output level drops like a rock, -15dBm or so. Next I tried a 15K:600R transformer on the output, but the max output I got was around -5dBm.
So my questions are:
A) I thought transistors had a low output impedance. Is this not true of early germaniums? Or is the 8k2 resistor responsible for this?
B) If an output transformer won't work, can I make it impedance balanced? Would that require an 8k2 resistor or does the cap change things?