ElectroSuite.com – A nice Solar Power Amplifier Speaker by pstretz, this amplifier is meant to be used outdoors in the sun so there was no need for a battery. Also even if it charged a 9VDC battery it would only last about 15-20 minutes inside anyway.
Solar Power Amplifier Speaker by pstretz – instructables.com
ElectroSuite.com – Discrete FET Guitar Preamp by J. Donald Tillman.
ElectroSuite.com – 100W Guitar Amplifier Mk II.