In 1982-83 Ampeg made a short
lived ‘A’ series of effect pedals. They are very rare and quite
collectible. This is the A-3 Overdrive . These seem to be high
quality good sounding Japanese made effects. If you are patient they do
show up on eBay. I have the A-4 Phaser and really like it.
Here is a quote from Harmony Central, “I bought it for the amount of distortion that you can get out of it – very nice. It lets your guitar’s tone come through and adds a
very nice amount of distortion.”