I was googling around, and this concept gave me an idea, which in paper works, the thing is it wasn't working in real life with a guitar signal, since the output pretty much sounds like the input.
Imagine something like this, not exatly like this because the square wave has a 180 degree phase, but I think the result would be the same. In the collector it's the out of phase signal, in the emitter the original signal. I amplify the signal by a factor of 5.45, I would get, tops, a signal oscilating between 7.225V and 1.775V, being the bias 4.5V. Most likely, it's much less than that.
I mean I tried a lot of things, low pass filter after that, voltage follower, transistor buffer at input, everytime the result is the same. It seems like the signal is ignoring the transistor. I think it works well (the transistors), I tried with many transistors, and the result is the same for all of them. I tested all of them with a multimeter. I also tested R1 and R2 values from 10k to 150k.
The only time I got something working, was yesterday, when I connected by mistake a pnp transistor and the resistor of the emitter to + of an op amp, like below (basically 4.5V).
I didn't find the right solution
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