Wednesday, December 12, 2018

amp with voltage feedback and constance current?

The last amp was minimalistic this one has more components. Let's look at the sim.
It looks pretty good but I want to reduce low frequency response to reduce noise.
Reducing the capacitor values produces low frequency rejection.
I reduced the caps more and the low end lifted higher. In my build I used 56 pfd caps and the cutoff is about 200 Khz.
This is the final build except the C1 and C2 are 56 pfd. I did a little testing and found it to be more stable and noise free than previous designs. It should work with any general purpose transistor. The sim ran with the 2N2222 and 2N3904 gave a higher gain than the KSP10.
I put this one in a metal box. Maybe tomorrow  I can make a couple of pictures.
NOTE: I added the 4 ohm resistor in the emitter circuit to give a little more feedback and provide stability. It could work as well without it. The amp I made last week could have benefited from that addition.

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