Hello everyone! I want to make a transistor only small wattage amplifier, just for the fun of it. So I found this schematic at Nuts & Volts which works perfectly for a single channel (Fig.15):

http://www.nutsvolts.com/magazine/article/bipolar_transistor_cookbook_part_7

So I figure why not two channels? I copy and paste the exact same circuit for a second channel:

I put 8 Ohm resitors to simulate the speakers. However I'm starting to think that not-so-trivial things in Electronics are really not trivial. Because it doesn't work, neither on Proteus nor on the protoboard! Can someone explain me why?
Also, I haven't any schematics for this kind of amp on the internet.

 

If one works and the other doesn't, then they are not identical.
There's an apparent error in the second one.

 

You may be getting interference from one channel to the other.
Test amp 1 first test amp 2 Now put each on separate 9v batteries

 

R5 is set to 100%.
R10 is set to 60%. Try changing R10 to 100%

 

Thanks for the answers! I just found out the villain in the schematic! It turns out that Proteus has identical symbols for voltage and current function generators. So I accidentally used a sine current with 50mApk instead of a sine voltage with 50mVpk to generate the input signal for VIL. After correcting that, the simulation worked well for both channels!

The reason the circuit didn't work on the protoboard was another matter. I am using PJ325 Stereo P2 audio sockets, which has two shorted out terminals for the left channel. When a connector is pluged in, one of the terminals - the one I was using - gets disconnected from the cable. This is the reason why I could not hear anything on the left channel.

 

Always good to reply with the source of the problem. Brings proper closure.
Glad you got it working.