Here is what Mike says…

‘Roberts R606-MB, 70's Transistor Radio re-born.. Converted into a guitar practice amp using a hand-wired circuit. Vintage looks with modern convenience. 

Powered by 9v battery or 9v standard pedal power supply (centre negative, sleeve positive)

On/Off switch on the back with battery door and input jack as well as external 9v supply socket.

Single volume control on top with power LED.’