Transistor preamp to drive one LED

I am trying to build a 9 volt powered circuit that amplifies an audio signal around line level. The load is one or more LEDs. It must not use any op amps. Preferably one or two transistors. A level pot before or after the transistor is OK. 

Sourav Gupta

  Joined February 12, 2018      696

Monday at 02:11 PM

What is the specification of the input?

L

Leonard Jeffrey

  Joined October 22, 2021      7

Friday at 08:53 PM

A stereo line level input. Music coming from an audio mixer, for example.

Sourav Gupta

  Joined February 12, 2018      696

Monday at 02:11 PM

Look for Vu meter circuit using transistor. It will work.