If you have electronics old equipment, keep many long ago year, unknow build Electronic Project good. I begs for to advise pre tone control circuit this. By it can fine to decorate the sound Bass,Treble and Volume well.There is the prominent point that use transistor, But be of good quality of good sound doesn’t be defeated the circuit that uses the integrated circuit. By the thing that me observes clear, be the noise is low, bland sound are good. from your circuit can use transistor number C945 or C828 or C1815 can replace. Which the price is inexpensive the hardware is other may get not difficult. The power supply , should choose that be model dc regulator 12V to 24V building may use PCB a bird purposes all right which , good easy.