paraphrased from a listing on retrofret.com:

This fearsome little beast is Gibson's equivalent to Fender's ubiquitous tweed Champ, putting out a big 5 watts of very serious growl. Paired in 1960 with the Korina Skylark steel guitar as a student level set, the GA-5 had previously been designated the "Les Paul Jr. TV" amp. The sound of a late 50's Junior, or any other guitar with a similar output through this golden blonde honker is inspiring, to say the least! Despite an impressive total of 3234 being shipped in 1960 these do not show up as often as we might like today.

Like the Fender Champ, the GA-5 sports a single volume control and two instrument inputs, though, unlike that competitor it is provided with the luxury of a wholly separate power switch! The tubes are the expected compliment of a 12AX7, a single 6V6 and a 5Y3, in this case all Silvertone glass. This is one of Gibson's coolest period amps, with a lot of tone for not being much bigger than a lunchbox!

4-5 Watts Tube Power

1x 6V6 Power Tube

1x 12AX7 Preamp Tube

1x 5Y3 Rectifier Tube

Upgraded 8" ToneTubby Hemp Cone Speaker

2x Inputs

Single Volume Knob

Original Internals

This amplifier is in Very Good condition, showing signs of moderate use and careful storage. The serial number on this amp is 19022 and the print on the control panel is fading with areas of loss. This amplifier's covering shows acceptable wear for its age with no areas of tears or loss. The original leather handle is intact. The Gibson logo from the front of the amplifier is lost to time. The original speaker has been replaced with a ToneTubby Hemp Cone 8ohm Speaker. This amp has been tested and functions as intended. Crank it hard and use your guitar's volume to control the gain. Or use this lunchbox amp as your secret weapon in the studio as an iconic clean tone or pedal platform. This amp is being sold AS-IS.