#audio

I've been working on this amplifier for about 4 days. Here's the circuit so far. The amplifier working good until the Vpeak input reach 0.6 Vp. the signal get distorted. i don't know how to improve my amplifier. Here's my calculation : First stage (Common Emitter) Zi = 2.1k ohm Zo = 6k ohm Ic...

Suddenly an amplfier shows terrible noise on the digital input. The internal pre amplifier is supplied by the source below, which has about 1V ripple on its +/- 21 volts output. Could that be the cause? No idea what the output looked before the noise occured. But I assume supply voltage to a DAC...