If you have any practice amps that you have not used or somehow not working anymore, then it is the best time to give it a make-over, I'll give you an inspiration on how to give your amp a new breathe of life.
In this instrcutable I will build an amplifier out of salvaged parts from existing guitar amp that I have and add other circuits to give new sound to the amp. One good thing about this is that it is cheap.
I salvaged a damaged 10watt practice amp and a 150watt PA amp that I have a long time ago, I made other circuits to give the old amp a new sound.
You have the option to build it in a combo type manner or a cool looking amp head.
Step 1: Gather the parts
Any salvageable amplifier,
soldering Iron and lead
cutting tools(wire cutter, strippers and the likes)
breadboard(fro prototyping and testing circuits before soldering it)
PCB, Ferric acid(if you like to etch)
universal PCB(if you hate to etch)
components(resistor, opamp, transistors, diodes, capacitors etc.)
9-12volt power supply(use to test your circuit) or a 9v battery
I decided to build the simplest circuits (since I it is difficult to find most of the parts needed for complex circuits especially in the country where I am from). any circuit you can think of can be used whether it is a transistor, op amp or valves(but I would discourage you with using valve pre amp since it would just kill the beauty of the valve sound if you pair it with a 10 watt practice amp it is not worth it).
-->Tonemender from runoffgroove
-->Trotsky overdrive from beavis audio
-->some tone stack designs.
This may vary as to what is available that you have right now.
but for my design I used