The Voltage at the minus side of C1 should be half the 9V battery Voltage. If the Voltage there is too low, increase the resistance of R2. If the Voltage there is too high, decrease the resistance of R2.
If Q1 and Q2 are too hot, install a resistor across one of the diodes, D1 or D2. Try a 1K or 470 Ohm or go lower until Q1 and Q2 cool off.
This circuit is too simple. It won't work at all 99% of the time. If it does work, performance will not be very good. An LM386 is easier to use and will work most of the time without adjusting any resistors.
The preamp is another crappy circuit. Find something else.
If Q1 and Q2 are too hot, install a resistor across one of the diodes, D1 or D2. Try a 1K or 470 Ohm or go lower until Q1 and Q2 cool off.
This circuit is too simple. It won't work at all 99% of the time. If it does work, performance will not be very good. An LM386 is easier to use and will work most of the time without adjusting any resistors.
The preamp is another crappy circuit. Find something else.