MINIMITE
Here's a little 7 watt single
ended tube guitar amp. It was built into a brand new case from a cheapo
Chinese solidstate amp,that I paid less than 50 bucks for. I used the
case and speakers, and gutted the electronics to make way for a brand
new tube circuit.
This amp uses only two tubes, a 12AX7 for gain & drive and a 6V6 run in Class A, for power. The circuit is based on a "Mini Plexi" type,that I found on the internet.
It has a electric input & a separate input biased for acoustic guitar. There is a Drive control, that sets the gain and amount of overdrive, a Marshall type tone stack ,and a Master volume.
I added a Standby switch,
because I used solid state rectification.
I had to come up with a voltage
doubler to wring enough power out of that little power
transformer.With the doubler, I get 360 volts of DC, for the
B+. The circuit is wired "point to point" using a skinny turret
board. 
Here is a veiw of the back of the amp,with the back cover removed. I used four seperate capacitors,to form the filter bank for the power supply.I had a switch ,to toggle between pentode & triode operation of the power tube,but I was not happy with the result, so I removed the switch & run the amp in pentode mode. The 'Coarse' & 'Crystal' switch allows for a higher gain overdriven sound or a cleaner setting.