This is a different variation of the first amp, but takes it a little further... I have this one in my supergun connected to the normal speaker wires via a
double pole switch - when a game requires amplification I just flip the switch! Works a treat! Here's the details:

Parts:

• LM380
• MKS2 0.1uF 63vdc capacitors X 2
• 470uF 16v radial electrolytic capacitor
• 10K miniature horizontal carbon trimmer
• 2R7 1/4Watt resistor
• 10K 1/4Watt resistors X 2
• Stripboard
• Optional - 14 pin DIL socket

This is how the circuit looks:

Again, you can build this however you wish to interpret it. I highly recommend using a DIL socket though, in case the amp blows or something - it'll save a lot
of heartache later on... If you can't get hold of the MKS2 caps you can use any 0.1uF 63vdc (or higher) capacitors.

Here's a more detailed picture of how to build the circuit onto stripboard: