Hello guys , I'm new to amplifier design .I need to design a preamplifier to be used for amplifying guitar frequencies. The last stage is a power amplification stage but my question is how to connect the power amplifier to the preamplifier. If I use the power amplifier below from my book, its input impedance will be too low if an 8 ohm speaker is used ( Bre is low) which will decrease the gain of my preamp.